• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.1
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• pp.45-52
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• 2016

Blast furnaces are crucial equipment for steel production. A typical furnace risks unexpected accidents caused by contraction and expansion of the walls under an environment of high temperature and pressure. In this study, an acoustic emission (AE) monitoring system was tested for evaluating the large-scale structural health of a blast furnace. Based on the growth of shell cracks with the emission of high energy levels, severe damage can be detected by monitoring increases in the AE energy parameter. Using this monitoring system, steel mill operators can establish a maintenance period, in which actual shell cracks can be verified by cross-checking the UT. From this study, we expect that AE systems permit early fault detection for structural health monitoring by establishing evaluation criteria based on the severity of shell cracking.

• Current Research on Agriculture and Life Sciences
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• v.31 no.3
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• pp.209-216
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• 2013

This study compared the antioxidant activity and functional constituents of the peel, flesh,and placenta of oriental melons according to the harvest time. The sample oriental melons were harvested during the major harvest time (from June to August) and divided into peel, flesh, and placenta. To examine the antioxidant activity and functional constituents, the sample melons were extracted using EtOH. As a result, the functional constituents and antioxidant activity of the oriental melons were found to change according to the harvest time. The total phenol and total flavonoid contents were highest in the samples harvested in June, and lowest in the samples harvested in July. Meanwhile, the antioxidant activities were estimated using an ABTS and FRAP assay, where the samples harvested in June also showed the strongest the antioxidant potential, while the samples harvested in July showed significantly lower antioxidant activities. This means that the climate influences the synthesis of secondary metabolites. The above data also suggests that oriental melons harvested in June contain more functional phytochemicals, making them more beneficial for human health.

• Resources Recycling
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• v.29 no.1
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• pp.3-16
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• 2020

This work provides an overview of the steel production process, pretreatment and tramp elements of scraps and recycling technology of dust generated from steelmaking process. Steel is the most common metal used by mankind, with the world production of crude steel in 2018 exceeding 1.8 billion tonnes. Recycling of ferrous scraps reduces CO₂ emissions by about 42 % and saves about 60 % of energy, compared to production steel from iron ore. Steel scraps are usually recycled to both an electric arc furnace (EAF), scrap-based steelmaking and the basic oxygen furnace (BOF), in ore-based steelmaking. EAF steelmaking, which uses iron scrap as a main raw material, is changing to an energy-saving type with a device for preheating scrap. Dust generated from the steelmaking process is recycled in various ways in the steel mill to recover iron and zinc.

• Korean Journal of Labor Studies
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• v.17 no.1
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• pp.209-242
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• 2011

본 연구는 현대하이스코 순천공장과 포스코 광양제철소에서의 비정규직 조직화 비교를 통해 사내하청 노동조합의 조직화에 영향을 미치는 작업장 요인과 지역사회 요인들을 살펴보고자 하였다. 기존의 비정규직 노동자 조직화를 비롯한 노동운동, 노동조합 관련 연구들은 대부분 '생산의 정치'의 영역에서 비롯된 '작업장' 요인들에 초점을 맞추고 있다. 그러나 비정규직 노동자 조직화에 대한 보다 분석을 보다 발전시키기 위해서는 작업장뿐만 아니라 '스케일의 정치'가 작동하는 공간인 '지역사회' 또한 분석의 단위로 통합되어야 한다. 따라서 본 연구는 작업장에서의 정규직 및 비정규직 노동자들에 대한 관리통제와 실천뿐만 아니라, 지역사회의 다양한 요인들이 비정규직 노동자들의 조직화 시도에 어떠한 영향을 미치는지를 검토하고자 한다. 두 사례에서 사내하청 노동자들은 철강산업이라는 산업부문과 사내하청 고용형태에 속한다는 공통점 외에도 낮은 수준의 임금과 노동조건하에서 강한 불만을 지니고 있었으며, 원청 및 사내하청 업체의 강한 통제하에 놓여 있었다는 공통점을 지닌다. 그럼에도 포스코의 경우와 달리 현대하이스코 비정규직 노동자들은 격렬한 대중투쟁과 지역사회의 지원 속에서 성공적인 조직화를 이룰 수 있었다. 사내하청 노동조합 결성 과정 또한 상이하였다. 현대하이스코의 경우 누적된 사내하청노동자들의 불만이 계약해지를 계기로 일순간 터져 나오면서 작업장 점거농성을 비롯한 대중투쟁과 결합하였다. 나아가 현대하이스코 비정규직지회는 지역사회운동과의 연대를 통해 작업장의 문제를 전체 비정규직 노동문제로 확대해 나갔다. 반면, 포스코의 경우 초기 조직화의 범위가 제한적이었고 대중투쟁 또한 강하게 나타나지 않았으며 지역사회의 관심과 지원 또한 약하게 나타났다. 이상과 같이 두 사례를 비교 검토함으로써 비정규직의 조직화에 있어 비정규직 자체 동원기제와 정규직의 지원은 여전히 중요하게 작용하지만, 이것이 확보되지 않을 경우 지역사회를 비롯한 외부의 지원이 일정하게 작용함을 살펴볼 수 있었다. 그러나 이 역시 지역사회구조 및 지역사회운동의 성격에 영향을 받는 것으로 나타났다.

• Journal of the Economic Geographical Society of Korea
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• v.24 no.1
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• pp.1-13
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• 2021

The POSCO Outsourcing Partners(POSOP) consisted of 59 companies plays an important role in creating jobs in Gwangyang City of Jeonnam Province, the representative steel city of Korea. However POSOP are suffering from a job shortage. The purpose of this study is to analyze the mismatch between job-seekers and job-openers in relation to employment in Gwangyang City. As a result of the job-mismatch analysis of nine factors, there was a clear mismatch in recognition of suppliers, access to corporate and employment information, employment information acquisition path, and employment preference factors. However, there was no mismatch in the factors of employment avoidance and difficulty in the job-seeking and recruitment process. As solutions to the mismatch, it proposes to redefine the role of POPOS, promote capacity building projects for labor-management co-prosperity and cooperation, and gradually promote related projects in connection with the master plan related a comprehensive plan for youth jobs.

• Resources Recycling
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• v.30 no.1
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• pp.35-43
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• 2021

In this study, Na2SO4 and KCl reagents were used to synthesize K2SO4 as a basic study for recycling byproducts generated during the manufacture of steel and cement. The mole ratio of Na2SO4 to KCl, the saturation of the solution, and the stirring temperature were controlled to derive the optimal manufacturing conditions. The microstructure and crystallinity of the materials prepared were evaluated using scanning electron microscopy and X-ray diffraction analysis. Pure K2SO4 was obtained when the mole ratio of Na2SO4 to KCl was 1:6-18, the saturation of the solution was less than 160%, and the stirring temperature was 20℃, 50℃. The optimal manufacturing conditions to maximize the crystallinity and yield of K2SO4 while minimizing the energy consumption were 1:6 mole ratio of Na2SO4 to KCl, 140% saturation of the solution, and 20℃ stirring temperature.

• Journal of the Korea Computer Graphics Society
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• v.24 no.5
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• pp.11-19
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• 2018

In this paper, we propose an algorithm for improving the accuracy and rate of convergence when two point clouds with noise and a low overlapping area are registered to each other. We make the most use of the geometric information of the underlying geometry of the point clouds with noise for better accuracy. We select a reasonable region from the noisy point cloud for registration and combine a modified acceleration algorithm to improve its speed. The conventional accuracy improvement method was not possible in a lot of noise, this paper resolves the problem by selecting the reasonable region for the registration. And this paper applies acceleration algorithm for a clone to low overlap point cloud pair. A simple algorithm is added to the conventional method, which leads to 3 or 4 times faster speed. In conclusion, this algorithm was developed to improve both the speed and accuracy of point cloud registration in noisy and low overlap case.

• Korean Journal of Materials Research
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• v.29 no.8
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• pp.497-504
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• 2019

In this study, the correlation between microstructure and Charpy impact properties of FCAW(Flux cored arc welding) HAZ(Heat affected zone) of thick steel plates for offshore platforms was investigated. The 1/4 thickness(1/4t) location HAZ specimen had a higher volume fraction of bainite and finer grain size of acicular ferrite than those of the 1/2 thickness (1/2t) location HAZ specimen because of the post heat effect during the continuous FCAW process. The Charpy impact energy at $-20^{\circ}C$ of the 1/4t location HAZ specimen was lower than that of the 1/2t location HAZ specimen because of the high volume fraction of coarse bainite. The Charpy impact energy at -40 and $-60^{\circ}C$ of the 1/2t location HAZ specimen were higher than those of the 1/2t location HAZ specimen because the ductile fracture occurred in the fine acicular ferrite and martensite regions. In the ductile fracture mode, the deformed regions were observed in fine acicular ferrite and martensite regions. In the brittle fracture mode, long crack propagation path was observed in bainite regions.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.4
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• pp.135-146
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• 2019

Deep beam has high section modules compared with shallow beam of the same weight. However, deep beam has low rotational capacity and high possibility of brittle failure so it is not possible to apply deep beams with a long span to intermediate moment frames, which should exhibit a ductility of 0.02rad of a story drift angle of steel moment frames. Accordingly, KBC and AISC limit the beam depth for intermediate and special moment frame to 750mm and 920mm respectively. The purpose of this paper is to improve the seismic performance of intermediate moment frame with 1200mm depth beam. In order to enhance vulnerability of plastic deformation capacity of deeper beam, Multi-Reduced Taper Beam(MRTB) shape that thickness of beam flange is reinforced and at the same time some part of the beam flange width is weakened are proposed. Based on concept of multiple plastic hinge, MRTB is intended to satisfy the rotation requirement for intermediate moment frame by dividing total story drift into each hinge and to prevent the collapse of the main members by inducing local buckling and fracture at the plastic hinge location far away from connection. The seismic performance of MRTB is evaluated by cyclic load test with conventional connections type WUF-W, RBS and Haunch. Some of the proposed MRTB connection satisfies connection requirements for intermediate moment frame and shows improved the seismic performance compared to conventional connections.

• Journal of the Korean GEO-environmental Society
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• v.12 no.1
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• pp.35-40
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• 2011

Magnesia-carbon brick is used to refractory material in Converter and/or Ladle furnace for molten steel manufacturing. The rapid growth of steel making industry, molten steel industry is increased. Therefore, growth of molten steel industry lead to make waste magnesia-carbon brick by repair of Converter and/or Ladle furnace. These waste magnesia-carbon brick is abandoned all. Besides, as it is loosely composed of silt and clay including sand falling according to the type of gangue, rainwater inflows and outflows relatively easily, but silt or clay particles absorb water for a long period, weakening ground. This study tried to show that when colluvial soil is solidified using waste magnesia-carbon brick powder as a way to solidify strengthen the rigidity of colluvial soil.