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형상기억합금으로 능동구속된 콘크리트 기둥의 해석모델 개발
정동혁 ( Jung¸ Donghyuk ),정새벽 ( Jeong¸ Sae-beyok ) 한국복합신소재구조학회 2021 복합신소재구조학회논문집 Vol.12 No.5
지난 수십 년간 발생한 강진으로 인해 철근의 내부 구속력이 부족한 철근 콘크리트(RC) 기둥에 수많은 심각한 피해가 발생하였다. 다양한 보수공법 중 형상기억합금(SMA)을 이용한 능동구속 기법은 지진에 취약한 RC기둥의 휨 연성을 높이는데 유의미한 결과를 보였다. SMA로 구속된 RC기둥의 동적거동에 관한 연구는 선행 연구자들에 의해 실험적으로 수행되었지만 구조적인 모델 개발은 거의 수행되지 않았다. 따라서 본 연구에서는 다양한 조건에서 능동구속된 RC기둥의 지진 시 거동을 확보하기 위해 SMA와이어로 보강된 RC 기둥의 진동대 실험 결과를 바탕으로 한 능동구속된 RC 기둥의 해석 모델을 제안한다. 제안된 해석모델은 양방향 지진력에 의한 SMA- RC기둥의 동적 거동 및 손상 정도를 확인할 수 있는 것으로 나타났다. Several reinforced concrete (RC) columns have been severely damaged by prior earthquakes because of the lack of sufficient internal steel confinement. Among various retrofitting methods, active confinement technique using shape memory alloy (SMA) showed promising results in improving the flexural ductility of seismically deficient RC columns. Although previous studies have experimentally investigated the seismic responses of SMA-confined RC columns, their structural models were rarely developed. This study develops analytical models of actively confined RC columns based on the shake table testing of RC columns retrofitted with SMA wires to estimate the seismic responses of actively confined RC columns under various conditions. It is demonstrated that the proposed analytical models can capture the dynamic behavior and damage status of SMA-confined RC columns under bidirectional seismic excitations.
Evaluation of photocatalytic activity of carbon-doped TiO2 films under solar irradiation
Donghyuk Jung,Byung Woo Kim,Gyusun Kim,Moon-Sun Kim 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.6
We proposed a method to obtain carbon-doped TiO2 (C-TiO2) with a higher photocatalytic activity for degradation of toluene. Solar radiation was used as a visible light source for photocatalytic oxidation. An optical fiber reactor (OFR) was used to investigate the photocatalytic oxidation of toluene in air. All C-TiO2 films used as catalysts were synthesized by a modified sol-gel and combustion method using carbon nanoparticles. The performance of the OFR using C-TiO2 was evaluated under various experimental conditions. The effects of solar flux, surface sensitization, inlet concentration of toluene and concentration of carbon nanopowder in C-TiO2 were examined.
Optimum empty bed retention time for toluene degradation in a biofilter packed with ceramic beads
Donghyuk Jung,김병우,Jieun Lee 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.9
Toluene is a toxic air pollutant and a common constituent emitted from industrial processes including chemical manufacturing operations, painting, and petroleum refining. We previously developed a new biofilter system the degradation of acetone and MEK. In this study, we evaluate the optimum EBRT to achieve an effective elimination capacity (EC) with smaller filter bed volume. In addition, we optimized the operation conditions for toluene degradation using the same biofilter system.