• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.6
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• pp.514-518
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• 2004

Many methods are used in the measurement of antioxidative capacity. These meth­ods require very complex procedures and pretreatment. Our suggestions for research will be simple and accurate methods for obtaining many kinds of samples, especially colored samples such as natural product extracts for measuring antioxidative capacities. For oxidation-reduction potential (ORP) system value, we examined the relationships between the ORP-pH system and the ORAC, FRAP methods. To evaluate ORP System value, we calculated the absolute slope/intercept from the linear regression of each standard material at different concentrations and ORP-pH system, and compared the correlations with ORAC and FRAP values.

• Journal of Korean Society on Water Environment
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• v.21 no.6
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• pp.595-601
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• 2005

In this research, effects of water circulation on phosphorus release from sediment into water body were studied. Sediments sampled at the Daechung Lake were used for the column experiments with circulation and non-circulation conditions. Deaeration coefficient, $K_1$ and reaeration coefficient, $K_2$ of non-circulation condition were 0.133 and 0, respectively, while $K_1$ and $K_2$ for circulation condition were 0.46 and 0.018, respectively. Oxidation Reduction Potential (ORP) showed a linear relationship with dissolved oxygen (DO) when DO is over 2 mg/L. Phosphorus concentration induced by phosphorus release from sediment was highly dependent upon DO, ORP, and pH. Under anaerobic condition, phosphorus release rate was higher for $Fe^{2+}$-bounded phosphorus compared to that of $Ca^{2+}$-bounded phosphorus.

• Resources Recycling
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• v.26 no.2
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• pp.18-24
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• 2017

The $FeCl_3$ solution has been used as an etchant for etching of metal. It is necessary to reuse the etching solution because waste $FeCl_3$ etchant generated after use has provided environmental and economic problems. In this study, HCl was mixed with the $FeCl_2$ solution and then $H_2O_2$ was added into the mixed solution to oxidize the $Fe^{2+}$. During the oxidation process, oxidation-reduction potential (ORP) was measured and the relationship between ORP and oxidation ratio was investigated. As a result, this study found that the ORP was increased with increasing the concentration of HCl and $H_2O_2$, while the ORP is decreased with oxidation progress. Such a behavior was in good agreement with Nernst's equation. Also, the oxidation efficiency reached about 99% when a sufficient amount of HCl and $H_2O_2$ were added.

• Journal of Korean Society on Water Environment
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• v.18 no.4
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• pp.371-377
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• 2002

The purpose of this study is to develop effective operating process in order to achieve more suitable conditions of Anoxic-Oxic-Anoxic-Stripper(AOAS) SBR through real-time control. To improve the removal efficiency, glucose, methanol and synthetic food waste acid fermentant were added as an external carbon source, In the case of glucose and synthetic food waste acid fermentant, TN, TP were removed to average 86.9%, 73.0% respectively. Methanol was removed to average 64.6%, 55.4% respectively. The synthetic food waste acid fermentant proved to be the most efficient and allowed for the substitution of an external carbon source. The removal rate of $COD_{Cr}$, was approximately 90% at all cases. The results of the study that a correlation between ORP (Oxidation-Reduction Potential), pH and DO and nitrification or denitrification when an external carbon source is added and when it isn't was showed that ${\Delta}ORP$ is suitable parameter. ORP reacted properly to denitrification (${\Delta}ORP<-10$) and nitrification (${\Delta}ORP<0$). The use of real-time control saved anywhere between 61 and 67 minutes at the anoxic(1) stage and 26 to 52 minutes at the oxic(1) stage. When the time saved from the anoxic(1) and oxic(1) was added to the anoxic(2) stage for the removal efficiency of TN and TP increased from 0.7 to 13.9% and 12 to 35 % respectively.

• Economic and Environmental Geology
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• v.47 no.1
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• pp.61-69
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• 2014

As we are trying to in-situ treat (purify or immobilize) heavy metals or radionuclides in groundwater, one of the geochemical factors to be necessarily considered is the value of oxidation/reduction potential (ORP) of the groundwater. A biogeochemical impact on the characteristic ORP change of groundwater taken from the KAERI underground was observed as a function of time by adding electron-donor (lactate), electron-acceptor (sulfate), and indigenous bacteria in a laboratory condition. There was a slight increase of Eh (slow oxidation) of the pure groundwater with time under a $N_2$-filled glove-box. However, most of groundwaters that contained lactate, sulfate or bacteria showed Eh decrease (reduction) characteristics. In particular, when 'Baculatum', a local indigenous sulfate-reducing bacterium, was injected into the KAERI groundwater, it turned to become a highly-reduced one having a decreased Eh to around -500 mV. Although the sulfate-reducing bacterium thus has much greater ability to reduce groundwater than other metal-reducing bacteria, it surely necessitated some dissolved ferrous-sulfate and finally generated sulfide minerals (e.g., mackinawite), which made a prediction for subsequent reactions difficult. As a result, the ORP of groundwater was largely affected even by a slight injection of nutrient without bacteria, indicating that oxidation state, solubility and sorption characteristics of dissolved contaminants, which are affected by the ORP, could be changed and controlled through in-situ biostimulation method.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.6
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• pp.703-710
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• 2011

Odor emission from domestic sewer systems has become a serious environmental problem. An investigation on a sewer manhole revealed that anaerobic decay of sediment organic matters (SOMs) and related declines of oxidation reduction potential (ORP) in the sediment layer were the main reason of the production of volatile sulfur compounds. In addition, as the anaerobic decaying period continued, the odor intensity rapidly increased with increasing concentrations of $H_2S$ and dimethyl sulfide. As a feasible method to control SOMs and to minimize odor emission potentials, an electrolytic oxidation process has been employed to the sediment sludge phase. In this study, voltages applied to the electrolytic oxidation process were varied as a main system parameter, and its effects on odor removal efficiencies and reaction characteristics were investigated. At the applied voltages greater than 20 V, the system efficiently oxidized the organic matter, and the ORP in the sludge phase increased rapidly. As a consequence, the removal efficiency of hydrogen sulfide was found to be >99% within 60 minutes of the electrolytic oxidation. Overall, the electrolytic oxidation process can be an alternative to control odor emission from sewer systems, and a threshold input energy needs to be determined to achieve effective operation of the process.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.05a
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• pp.96-98
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• 2006

축산폐수는 축사가 대부분 상수원보다 상류지역에 산재하고 있어 이를 효과적으로 관리하기 어려우나, 연속 회분식 반응기(Sequencing Batch Reactor, SBR)는 장치가 간단하고 경제성이 우수하여 축산폐수처리에서 효율적으로 적용될 수 있다. 본 연구에서는 DO(Dissolved Oxygen)과 ORP(Oxidation-Reduction Potential)을 이용하여 지식기반 고장진단 시스템을 제안하였다. 실시간으로 얻어진 ORP, DO값들을 전처리하여, [ORP], [DO]외에 [ORP DO]합성data와 ORP, DO의 특징백터의 합에서 얻어진 fusion data의 총 4개의 data set을 이용하여 각각에 대한 진단과 분류성능을 검토하였다. 이 값을 이용하여 FCM (fuzzy C-mean) 클러스터링 한 후, K-PCA과 LDA로 차원축소시켜 특징백터를 추출하였다. 그리고 Hamming distance로 test data와 특징백터의 거리를 계산하여 각 class를 F1에서 F8까지 분류하였다. 그 결과 데이터를 그대로 이용하는 것 보다 차분데이터형태로 이용하는 것이 우수했으며 그 중 fusion 데이터의 결과가 다른 것들보다 향상된 결과를 보였다. 그리고 K-PCA와 LDA를 결합한 결과가 다른 방법에 비해 우수한 결과를 보였으며 fusion method를 이용한 최고인식율은 98.02%를 나타내었다.

• The Journal of Engineering Geology
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• v.17 no.1 s.50
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• pp.143-150
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• 2007

AMD (Acid mine drainage) from disused mines is one or the most significant pollutant problems to make harmful effect to human health. We demonstrated the mechanism of resolution and adsorption reaction for arsenic, manganese and zink from the soil and mine tailings which were located in the vicinity of a disused mine in Kyoungnam area. The resolution experiments were carried with a column test f3r 45 days continuously. Metal chemical forms in water were changed with the condition of solution pH and ORP (oxidation-reduction potential). Metal chemical forms affected on the reaction of resolution and adsorption of metals in water environments. Even though the sampling was carried in very closed location, there was significant different results of pollution level and ORP changes in terms of column operations. Hence It was important to note the pH and ORP in AMD to evaluate a risk assessment and a soil management using monitoring metals. When we operate AMD management with the mechanism of resolution and adsorption it can be achieved better economic solution.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.4
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• pp.243-248
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• 2022

The purpose of this paper is to etching SUS MASK by adding an additive (F300) to FeCl3. The equipment used in the experiment is a self-made automatic liquid management system. The automatic liquid management system is a device capable of controlling the Oxidation Reduction Potential (ORP) and specific gravity in real time and supplying FeCl3 and additives in a quantitative manner. SUS MASK was etched in units from 10 sheets up to 200 sheets for 1 minute. It was confirmed that when the initial SUS MASK was 10 sheets, the ORP value started with 628 mV and measured at 611 mV from the time of 40 sheets being injected, and maintained close to 610 mV up to 200 sheets. The specific gravity was maintained near 1.640. And the SUS MASK was measured close to 0.4 mm from 50 sheets to 200 sheets. The experimental conditions of ORP had a specific gravity of 610 mV, 1.463, an etching pressure of 3.0 kg/cm2, an additive (F300) ratio of 1.2%, and the hole size was measured by up to 200 sheets of 10 sheets at once etching. As a result, the diameter approached 0.4 mm from 20 sheets. Even if the number of SUS MASK was increased, the ORP and specific gravity were well controlled, and it was confirmed that the experimental target value was close to 0.4 mm.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.5-11
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• 2022

Despite the increasing importance of manufacturing and application R&D for ultrapure deionized water and electrolyzed ion water, various and systematic studies have not been conducted until now. In this study, the electrostatic discharge (ESD) behavior of electrolyzed ion water using a proton exchange membrane(PEM) was evaluated according to the type, flow rate, and bubble of electrolyzed ion water. In addition, by observing that Oxidation Reduction Potential (ORP) value returns to the unique value of electrolyzed ion water after electrostatic discharge, the possibility of two types of ions participating in electrostatic discharge ((H₂O)_n⁺ (assumed)) and ions for maintaining the characteristics of electrolyzed water could be inferred. In order to confirm the chemical structure and characteristics of the cations, in-depth research related to water molecular orbital energy or band gap should be followed.