• 대한환경공학회지
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• 제22권1호
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• pp.11-19
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• 2000

생물학적 폐수처리장의 효율을 정확하게 예측하기 위해서는 생물학적 동력학 계수와 화학양론적 계수를 반드시 추정하여야만 한다. 본 연구에서는 생물학적 동력학 계수를 추정하는 실험적 방법과 그 이론적 배경이 논의되었다. 또한 생물학적 동력학 계수 추정을 위해 신소이용률(Oxygen Uptake Rate, OUR)을 이용한 회분식 실험을 실시하였다. 호기성 상태에서 종속영양미생물과 독립영양미생물의 생물학적 동력학 계수를 추정하기 위한 간단한 방법이 기술되어 있다. 생물학적 동력학 계수 추정시 해석상의 부정확성 때문에 COD와 VSS농도를 이용하지 않고 산소이용률을 미생물 성장 자료로 변환하여 사용하였다. 종속영양미생물의 최대비성장율, 생산계수, 반속도상수, 사멸율을 산소이용률을 사용하여 추정하였다. 또한 독립영양미생물의 최대비성장율은 $NO_3{^-}$ 농도의 증가율로부터 추정하였다. 본 연구의 목적은 회분식 반응조에서 산소이용률을 이용해 종속영양미생물과 독립영양미생물의 생물학적 동력학 계수를 정확하고 간편하게 추정하는데 있다. 이러한 산소이용률을 이용한 생물학적 동력학 계수 추정 방법이 복잡한 활성슬러지 모델링에 도움을 줄 것으로 판단된다.

• Bulletin of the Korean Chemical Society
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• 제32권5호
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• pp.1679-1684
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• 2011

Interfacial reactions kinetics often differ from kinetics of bulk reactions. Here, we describe how the density change of an immobilized reactant influences the kinetics of interfacial reactions. Self-assembled monolayers (SAMs) of alkanethiolates on gold were used as a model interface and the Diels-Alder reaction between immobilized quinones and soluble cyclopentadiene was used as a model reaction. The kinetic behavior was studied using varying concentrations of quinones. An unusual threshold density of quinones (${\Gamma}_c$ = 5.2-7.2%), at which the pseudo-first order rate constant started to vary as the reaction progressed, was observed. This unexpected kinetic behavior was attributed to the phase-separation phenomena of multi-component SAMs. Additional experiments using more phase-separated two-component SAMs supported this explanation by revealing a significant decrease in ${\Gamma}_c$ values. When the background hydroxyl group was replaced with carboxylic or phosphoric acid groups, ${\Gamma}_c$ was observed at below 1%. Also, more phase-separated thermodynamically controlled SAMs produced a lower critical density (3% < ${\Gamma}_c$ < 4.9%) than that of the less phaseseparated kinetically controlled SAMs (6.5% < ${\Gamma}_c$ < 8.9%).

• 상하수도학회지
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• 제30권3호
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• pp.263-270
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• 2016

Recent Engineered nanoparticles were increasingly exposed to environmental system with the wide application and production of nanomaterials, concerns are increasing about their environmental risk to soil and groundwater system. In order to assess the transport behavior of silver nanoparticles (AgNPs), a saturated packed column experiments were examined. Inductively coupled plasma-mass spectrometry and a DLS detector was used for concentration and size measurement of AgNPs. The column experiment results showed that solution chemistry had a considerable temporal deposition of AgNPs on the porous media of solid glass beads. In column experiment, comparable mobility improvement of AgNPs were observed by changing solution chemistry conditions from salts (in both NaCl and $CaCl_2$ solutions) to DI conditions, but in much lower ionic strength (IS) with $CaCl_2$. Additionally, the fitted parameters with two-site kinetic attachment model form the experimental breakthrough curves (BTCs) were associated that the retention rates of the AgNPs aggregates were enhanced with increasing IS under both NaCl and $CaCl_2$ solutions.

• Bulletin of the Korean Chemical Society
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• 제27권11호
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• pp.1819-1824
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• 2006

The general objective of the present study was to investigate the potential application of the UV spectroscopic method for determination of the polymeric additives present in papermaking fibrous stock solutions. The study also intended to establish the surface-chemical retention model associated with the adsorption kinetics of additives on fiber surfaces. Polyamide epichlorohydrin (PAE) wet strength resin and imidazolinium quaternary (IZQ) softening agents were selected to evaluate the analytical method. Concentrations of PAE and IZQ in solution were proportional to the UV absorption at 314 and 400 nm, respectively. The time-dependent behavior of polymeric additives obeyed a mono-molecular layer adsorption as characterized in Langmuir-type expression. The kinetic modeling for polymeric adsorption on fiber surfaces was based on a concept that polymeric adsorption on fiber surfaces has two distinguishable stages including initial dynamic adsorption phase and the final near-equilibrium state. The simulation model predicted not only the real-time additive adsorption behavior for polymeric additives at high accuracy once the kinetic parameters were determined, but showed a good agreement with the experimental data. The spectroscopic method examined on the PAE and IZQ adsorption study could potentially be considered as an effective tool for the wet-end retention control as applied to the paper industry.

• 자원리싸이클링
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• 제26권3호
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• pp.17-25
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• 2017

전기로 제강분진은 고철을 전기로에서 용해하는 과정에서 발생하는 휘발성분들이 공기 중의 산소와 반응하여 산화물형태로 포집된 미세분말로써 다양한 특성을 가지고 있다. 이러한 전기로 제강분진의 효율적인 자원화를 위해서 반응속도론적 기초실험과 Pilot 규모의 생산실험을 병행하여 실시하였다. 그 결과 전기로 제강분진은 다양한 구성성분과 화합물로 구성되어 있었으며 공통적으로 Cl과 알카리 성분이 다량으로 존재함에 따라 자원화를 위한 실제 조업에 큰 악영향을 미치는 화합물의 형성이 예상된다. 휘발거동은 $1100^{\circ}C$ 영역에서 활발히 진행되고 $1250^{\circ}C$ 영역에서는 용융현상이 나타남을 확인할 수 있었다. 이러한 결과는 Pilot규모의 실증테스트의 결과로 얻은 조산화아연과 환원철의 형성거동에서도 동일한 결과를 얻었다. 이러한 결과는 전기로 제강분진의 자원화 플랜트의 설계 및 조업조건 설정에 유용한 기초자료로 활용이 기대된다.

• 수산해양기술연구
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• 제50권4호
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• pp.435-446
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• 2014

Tidal turbulence was examined using three-dimensional tidal velocity data observed at a trench offshore of Tongyoung, Korea. The kinetic energy and intensity, including the variation period of the flow velocity and direction, were used to investigate the relationships between tidal turbulence and fishing gear dynamics, including the effects of swimming fish during fishing operations. As the resultant velocity increased from 0.2 to 0.9 m/s, the kinetic energy also significantly increased, while the turbulence intensity decreased from 50 to 10%. Tidal flow in strong flow fields displayed shorter periods of between 4 and 10 s, as determined by fast Fourier transform, the global wavelet method, and peak event analysis, and the periods were compared with the period of response to swimming fish and to oscillation of fishing gear. As mean velocity increased, velocity amplitude also increased from 0.1 to 0.6 m/s, and its directional amplitude changed markedly from 20 and $90^{\circ}$. Our study suggests that tidal turbulence can influence fish behavior or fishing gear geometry during fishing operations, although our analysis considered only a limited area. In future work, observations should be carried out over a more extensive depth and area.

• Advances in environmental research
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• 제6권4호
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• pp.281-299
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• 2017

Single (0.005 M DTPA), sequential (six-step) and kinetic (0.05 M EDTA) extractions were performed to assess Cd, Cr, Cu, Ni, Pb, and Zn mobilization and their potential ecological risks in Abuja (Nigeria) water (WTS) and wastewater (WWTS) treatment sludges. Total metal levels (mg/kg) in WTS and WWTS, respectively were: Cd(3.67 and 5.03), Cr(5.70 and 9.03), Cu(183.59 and 231.53), Ni(1.33 and 3.23), Pb(13.43 and 17.87), Zn(243.45 and 421.29). DTPA furnished metal extraction yields (%) in WTS and WWTS, respectively as: Cd(11 and 6), Cr (15 and 7), Cu(17 and 13), Ni(23 and 3), Pb(11 and 12), and Zn(37 and 33). The metals were associated with the soluble/exchangeable, carbonate, Mn/Fe-oxide, organic matter and residual forms to varying degrees. Kinetic extractions cumulatively leached metal concentrations akin to the mobilizable fractions extracted sequentially and the leaching data fitted well into the Elovich model. Metal mobilities were concordant for the three leaching procedures and varied in the order:WTS>WWTS. Calculated ecological risk indices suggested moderate and considerable metal toxicity in WTS and WWTS, respectively with Cd as the worst culprit. The findings may be useful in predicting heavy metals bioavailability and risks in the sludges to guide their disposal and use in land applications.

• 한국수소및신에너지학회논문집
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• 제1권1호
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• pp.1-8
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• 1989

The hydriding kinetic mechanism and the change of the hydriding reaction rate of $MmNi_{4.5}Al_{0.5}$ during the thermally induced hydrogen absorption-desorption cycling are investigated. Comparison of the reaction rate data which are obtained by the pressure sweep method with the theoretical rate equations suggests that the hydriding rate controlling step has changed from the dissociative chemisorption of hydrogen molecules at the surface to the hydrogen diffusion through the hydride phase with the increase of the hydriding fraction. These hydriding kinetic mechanism is not changed during the cycling. However, the intrinsic hydriding reaction rate of $MmNi_{4.5}Al_{0.5}$ after 5500 cycles increases significantly comparing with the activated one. It is suggested that the change of the hydriding kinetic behavior due to intrinsic degradation of $MmNi_{4.5}Al_{0.5}$ can be interpreted as follows ; the formation of nickel cluster at the surface of the sample and the host metal atom exchange in bulk by thermal cycling.

• 한국분무공학회지
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• 제20권2호
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• pp.76-81
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• 2015

Swirl flow has an impact on the stabilization of the flame by the recirculation flow, improvement of the combustion efficiency. The swirl flow in the gun type burner is created by the spinner which is inside the airtube that guide the combustion air. Burner has generally the combustion device composed electronic spark plug, injection nozzle, combustion device adaptor, and spinner. These inner components change the air flow behavior passing through airtube. So, this study analyzed exhaust flow characteristics of the gun type burner according to the ratio of airtube diameter. Turbulence characteristics by the spinner was mean velocity, turbulence intensity, kinetic energy, shear stress and flattness factor of the air flow of axial direction and tangential direction from the exit of the airtube.

• 한국분무공학회지
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• 제20권2호
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• pp.70-75
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• 2015

Swirl flow in the gun type burner has an impact on the stabilization of the flame, improvement of the combustion efficiency. The swirl flow is created by the spinner which is inside the airtube that guide the combustion air. Gun type burner has generally the inner devices composed electronic spark plug, injection nozzle, combustion device adaptor, and spinner. These inner components change the air flow behavior passing through airtube. So, this study conducted the measurement using by hot-wire anemometer and analyzed effect of the swirl number of spinner on the exhaust air of gun type burner. Turbulence characteristics come up in this study was mean velocity, turbulence intensity, kinetic energy, shear stress and flattness factor of the air flow with the change of the distance of axial direction and tangential direction from the exit of the airtube.