• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.5
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• pp.9-17
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• 2006

Large steel industries have nonlinear loads such as electric arc furnaces. Harmonic field measurements have shown that the harmonic contents of a waveform varies with time. Direct application of the harmonic assessment to the snapshot measurements would result in ambiguous conclusions depending on which instant is sampled. A cumulative probablistic approach is the most commonly used method to solve time-varying harmonics. Harmonic simulations are performed to evaluate the harmonic voltage and current distortions throughout the system. This paper provides an in depth analysis on harmonics field measurement of the electric arc furnace loads, harmonics assessment by the international harmonic standards IEC 61000-3-6 and IEEE Std. 519 and harmonic simulation for the time-varying harmonics. The EDSA program was used as a simulation tool for the case study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.3
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• pp.533-544
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• 2015

Unlike the concrete structure built on land, that exposed to the marine environment is greatly degraded in durability due to the exposure to not only the physical action caused by sea wind, tide, and wave, but also the harsh conditions, including the chemical erosion and freeze-thaw which result from $SO_4{^{2-}}$, $Cl^-$ and $Mg^{2+}$ ions in seawater. In the process of the large scaled construction of submerged concrete structures, of course environmental hazardous substance, such as alkaline (pH) and heavy metals, may be leached. Thus, this issue needs to be adequately reviewed and studied. Therefore, this study attempted to develop a CSA (Calcium Sulfo Aluminate) activator using electric arc furnace reducing slags, as well as the eco-friendly concrete for artificial reefs using electric arc furnace oxidizing slag as aggregate for concrete. The strength properties of the eco-friendly concrete exposed to the marine environment were lower than those of the normal concrete by curing 28 days. This suggest that additional studies are needed to improve the early strength of the eco-friendly concrete. With respect to seawater resistance of the eco-friendly concrete, the average strength loss against 1 year of curing days reached 8-9%. the eco-friendly concrete using high volume of ground granulated blast furnace slags and high specific gravity of electronic arc furnace oxidizing slag demonstrated the sufficient usability as a freeze-thaw resistant material. With respect to heavy metal leaching properties of the eco-friendly concrete, heavy metal substances were immobilized by chemical bonding in the curing process through the hydration of concrete. Thus, heavy metal substances were neither identified at or below environmental hazard criteria nor detected, suggesting that the eco-friendly concrete is safe in terms of leaching of hazardous substances.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.70.2-70.2
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• 2010

고순도 금속규소는 반도체, 태양전지 및 규소화 화합물 등의 원료로 사용되어왔으며, 최근 태양전지 시장 확대로 인해 고순도 금속규소의 수요가 증가하고 있다. 그러나 전량 수입 중인 고순도 금속규소의 수급 안정성과 품질 균일성 등이 문제가 되고 있어, 고순도 생산 공정 및 생산 에너지를 절감 공정에 관한 연구 개발이 필요한 실정이다. 이에 본 연구에서는 금속규소의 원료인 규석(SiO2)과 카본(C)의 환원반응을 온도와 압력별로 살펴보고, 평형 상태의 금속규소수율 조건을 알아보았다. 그리고 아크로 내부 위치에 따른 산화/환원 반응식을 고찰하여 주요 반응식의 깁스 자유 에너지를 비교 분석 하였다. 본 해석을 통한 실험용 아크로 제작과 기초실험을 통해 금속 규소 생산 수율 및 순도를 평가하였으며, 생산된 실리콘의 최대 순도는 약 99.8%로 측정되었다.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.149-152
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• 2006

In this paper, we researched and compared the properties of steel slag(is divided with electric arc furnace slag and converter slag) as concrete aggregate by measuring physical and chemical characteristics of it. The steel slag mainly contains SiO2 and CaO as the chemical composition. The reaction with water and a little of free CaO in the slag causes slag's volume to expanse. Therefore, we used several aging methods in order to decrease the characteristics of slag volume expansion. The physical properties of steel slag aggregate is researched and then the strength of concrete with the steel slag aggregate is measured.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.227-230
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• 1998

The void ratio, continuous void ratio, coefficient of permeability, compressive strength and tensile strength were considered according to the EAF(Electric Arc Furnace) slag replacement and sand percentage in permeable concrete used with EAF slag as aggregate. The sand percentage was directly proportional to the permeable coefficient, but inversely proportional to the compressive strength. When the compressive strength and coefficient of permeability were 230 kg/$\textrm{cm}^2$ and 1$\times$$10^{-1}$ cm/sec, the useful sand percentage was 8%. When the EAF slag replacement was 25%, the coefficient of permeability was the most low and compressive strength was the most high.

• Magazine of the Korea Concrete Institute
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• v.5 no.3
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• pp.161-168
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• 1993

본 연구는 아스팔트 콘크리트의 채움재로서 제강더스트의 사용가능성을 실험을 통하여 분석하였다. 실험에는 제강더스트의 기본물성시험과 혼합물의 비교시험을 포함시켰다. 비교시험에서는 채움재로서 석회석분을 사용하는 경우와 제강더스트를 사용하는 경우, 채움재와 아스팔트를 혼합한 필리-비투먼, 그리고 골재까지 혼합한 아스팔트 콘크리트에 대하여 물성을 비교분석하였다. 실험결과 제강더스트는 포장용 채움재의 규정을 만족시키며, 제강더스트를 채움재로 사용한 아스팔트 콘크리트보다 우수하며, 제강더스트는 아스팔트 혼합물용 채움재로써 충분히 사용가능한 것으로 밝혀졌다.

• Journal of Technologic Dentistry
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• v.26 no.1
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• pp.41-48
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• 2004

Ti-20%Zr(-5%Cr) alloys not containing harmful Al and V were newly designed in order to reveal their possibility for dental casting and melted in an arc melting and casting furnace under Ar atmosphere. The corrosion resistance was studied by anodic polarization test. From the observation of anodic polarization behavior, it was found that the corrosion resistance was markedly increased by the addition of Cr. The corrosion resistance of Ti-20%Zr-5%Cr alloy was superior to that in Ti-6%Al-4%V alloy but almost similar to that in CP Ti using in market place today.

• Journal of the Korea Concrete Institute
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• v.11 no.3
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• pp.101-111
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• 1999

Compared with the BF slag, the EAF slag has expansion due to the reaction with water and free CaO. Therefore it is specified in Concrete Specification that the FAP slag aggregated must not be used in concrete. Because of this reason it is unusual to use the EAF slag aggregate in concrete. The EAF slag aggregate treated with accelerated and water aging was comparatively satisfied with fundamental properties, which are specific gravity, unit weight, abrasion and immersion expansion ratio, as concrete aggregate. Therefore when we measured the compressive strength till 28 days, we found that the mortar and concrete replacing the natural aggregate with the EAF slag aggregate by 4 steps had better results than the concrete using the natural aggregate in a view of the compressive strength. But at 91 days, concrete using the EAF slag aggregate had no difference with it using the natural aggregate.

• Journal of the Korean institute of surface engineering
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• v.37 no.1
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• pp.64-70
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• 2004

Cryogenic characteristics of austenitic stainless steel based on 304 steel with nickel and nitrogen were investigated at room temperature and $-196^{\circ}C$. The alloys were fabricated by vacuum arc furnace and cold working after homogenization treatment. The addition of nickel and nitrogen decreased the stability of $\delta$-ferrite and induced the stability against the formation of martensite to result significantly in enhancing ductility at $-196^{\circ}C$. Nitrogen reduced Md temperature, which was beneficial to the tensile strength and elongation at $25^{\circ}C$ and -196$^{\circ}C$.

• Journal of Power Electronics
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• v.6 no.3
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• pp.195-204
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• 2006

This paper presents a new compensating system, consisting of series and shunt active filters, for mitigating voltage and current disturbances. The shunt filter is used to compensate for unbalanced and distorted load currents. The series filter comprises two inverters, used to suppress voltage disturbances and handle source currents independently. This configuration is devised to reduce the overall cost of active compensators by using low-frequency high-current switches for the latter inverter. The filters are controlled separately using a novel control strategy. Since voltages at the point of common coupling contain interharmonics, conventional methods cannot be used for extracting voltage references. Therefore, voltage references are obtained from generated sinusoidal waveforms by a phase-locked loop. Current references are detected based on rotating frame vector mapping. Simulation results are presented to verify the system.