This study evaluates underwater non-thermal plasma (UNTP) as a reagent-free process for the complete mineralization of oxalic acid, a major chelating agent in nuclear decontamination effluents. Quantitative assessment was based on total organic carbon (TOC) removal and stable carbon isotope tracing with uniformly labeled ¹³C-oxalic acid. TOC and ion chromatography (IC) analyses demonstrated complete mineralization within 60 min at ≤ 300 ppm (k = 0.120, 0.100, 0.042 min⁻¹; t₉₀ = 19.2, 23.0, 55.0 min), whereas at 450 ppm partial mineralization remained (TOC 25.4 mg C/L after 60 min). At higher concentrations (1000–2000 ppm), TOC removal was restricted to 25–57% with rate constants decreasing to 0.008 and 0.003 min⁻¹ (t₉₀ = 288, 767 min); at 3000 ppm, reaction nearly stagnated (k = 0.0009 min⁻¹; t₉₀ ≈ 2558 min). Energy yield peaked at low/intermediate concentrations (0.9–1.3 g-C kWh⁻¹; 1.1 g-C kWh⁻¹ at 450 ppm) but declined to 0.9, 0.3, and 0.2 g-C kWh⁻¹ at 1000, 2000, and 3000 ppm. Mechanistic profiling showed that both glyoxylic and formic acids remained below the method detection limits (LOD) throughout the treatment period, supporting that a predominantly direct mineralization pathway to CO₂ was operative. Critically, ¹³C tracer experiments (300 ppm, 60 min) yielded δ¹³C = + 5702‰ (~ 7.0 atom % ¹³C), confirming the presence of substrate-derived carbon in the evolved CO₂. No solids or carbonate byproducts were detected, consistent with a nearly closed carbon balance. Bulk temperatures remained ≤ 40 °C under all conditions, confirming non-thermal operation. These findings establish TOC-based kinetics and isotopic evidence of oxalic acid mineralization, define a practical operating window (≤ 2000 ppm), and support UNTP as a sustainable route for treating chelating agents in decontamination effluents.

본 연구에서는 2011년부터 2024년까지 새만금 지역의 4개 주요 지점(만경강, 동진강, 신시갑문, 가력갑문)에서 수집된 수질 자료 를 이용하여 용존산소(DO)와 총유기탄소(TOC) 예측을 위한 XGBoost 기반 모델을 구축하고, SHAP 분석을 통해 변수별 상대적 설명력을 평가하였다. 모델은 DO에서 R² 0.89–0.95, TOC에서 0.88–0.95의 높은 예측 성능과 낮은 평균제곱오차(MSE)를 보여, 예측의 신뢰성을 확 인하였다. SHAP 분석 결과, 하천 지점에서는 pH와 수온이 DO 예측에서 가장 높은 설명력을 보였고, 염분의 영향은 미미하여 외해수 유입 이 제한적임을 나타냈다. 반면, 기수 지점에서는 수온이 DO 예측의 주요 요인으로, 염분은 보조 요인으로 작용하였다. 연도별 분석에서는 하천 지점에서 pH의 기여도가 2016년 이후 감소하고 수온의 비중이 2019년 이후 다소 높아지는 경향이 일부 나타났으나, 전체적으로는 명 확한 증가·감소 추세가 확인되지 않았다. TOC 예측에서는 하천 지점에서 COD와 chlorophyll-a가, 기수 지점에서는 chlorophyll-a와 염분이 상 대적으로 중요한 설명 변수로 확인되었다. COD의 기여도는 2017–2018년에 낮았다가 2019–2021년에 높아진 후 최근 다시 감소하는 등 일부 연도에서 변동이 나타났으나, 뚜렷한 장기 경향은 관찰되지 않았다. 이러한 결과는 연도별로 변수의 상대적 설명력에 세부적인 변동 은 존재하지만 전체적으로 일관된 추세는 아직 확립되지 않았음을 보여준다. 이처럼 연도별 변동성과 불확실성이 공존하는 환경에서, XGBoost와 SHAP을 결합한 접근법은 각 변수의 상대적 중요도와 시기별 변화를 정량적으로 평가할 수 있는 유용한 분석 틀을 제공한다.

Total organic carbon(TOC) was introduced as the water quality index of the rivers and lakes in 2013. This paper evaluated factors affecting effluent TOC concentrations and treated and discharged loads of existing publicly owned treatment works(POTWs). For selected POTWs with greater treatment capacity than 500㎥/day, factorial analysis was used to consider effects of kinds of biological treatment processes, inflow of other types of wastewater(industrial, livestock, landfill leachate wastewater, etc.) with domestic wastewater, sewer separation rate, and effluent discharging zones in which different effluent criteria applied. As a result, those factors did not show significant effect on effluent TOC concentration of POTWs in effluent discharging zone Ⅰ and Ⅱ. However, In effluent discharging zone Ⅲ and Ⅳ, kinds of biological treatment processes, the inclusion of other waste in influent of domestic wastewater, and the sewer separation rate were significant factors. The treated TOC load in POTWs was also not affected significantly by the variables set in this study. On the other hand, those three factors influenced significantly on the TOC load discharged to water bodies. The sum of factorial effects and the contribution rate of three factors to the discharged TOC load was 60.23 and 41%, 59.57 and 41%, and 42.04 and 18%, respectively.

Total organic carbon (TOC) will replace chemical oxygen demand (CODMn) as an effluent water quality standard in public sewage treatment works (PSTWs) from 2021 in Korea. To ensure effective control of TOC in the effluent, investigation was carried out into TOC levels and sewage treatment operation factors in five target PSTWs using anaerobic-anoxic-aerobic (A2O) processes, media, membrane, and sequencing batch reactor (SBR) technologies. TOC removal efficiencies appeared to be 93-96% on average. As a fraction of TOC, biodegradable dissolved organic carbon (BDOC) was reduced from 64% in the influent to 9% in the effluent in these PSTWs. During the investigation, biological treatment processes were applied flexibly for operation factors such as HRT, SRT, MLSS, F/M ratios and BOD volume loads, based on the influent characteristics and design conditions. As a result, we suggest efficient operating conditions in PSTWs by evaluating relationships between TOC removal and operation factors.

Recently domestic manufacturing companies have been experiencing worsening profitability and stunted growth due to the long-term economic recession and the rapid rise of developing countries such as China and Southeast Asia. These difficulties force many companies to concentrate their core competencies on new value creation and innovation in order to gain momentum for new growth. Enterprise Resource Planning (ERP) has been considered as one of viable solutions. Among the various modules in ERP, shop floor control function in the production management module is rather limited. In order to overcome this problem, Manufacturing Execution System (MES) has been used as a subsystem which has a strong information gathering power and flexibility. Both systems interact closely with each other. In particular, ERP requires fast, accurate shop floor information at MES. This paper describes how to synchronize relevant information between ERP and MES with theory of constraints (TOC). The processing time information transmitted from the MES workplace is received at the ERP workplace. In the process, the received processing time is causing information distortion in ERP, when the information gathering standard of MES is different from the ERP information interpretation standard. The Drum-Buffer-Rope theory of TOC was applied to resolve this problem, therefore, information synchronization between both systems was made. As a precondition, the standard time of the upper ERP system was rearranged according to the capacity constraints resource. As a result, standard time restructuring has affected changes in labor costs. Standard labor costs have come close to actual ones, and information synchronization of MES transmission data has improved the reliability of standard product costs, such that it enabled various company-wide restructuring actions to be much more effective.

Recently, many business and government organizations have benefitted by executing projects using TOC-CCPM(Theory of Constraints-Critical Chain Project Management). In parallel, Earned Value Management(EVM) metrics have also become popular. Many organizations like US government requires that all large projects measure and report project progress status using EVM. Thus, project management in business fields such as plant construction, IT development, ship building need to integrate TOC-CCPM and EVM in oder to keep and reduce the delivery date of projects for improvement of customer satisfaction and enlargement of business opportunity. This paper proposes the scheme and case of developing the Synchro-EVM system which TOC-CCPM and EVM are connected.

As the Enforcement Ordinance of Environmental Policy Act was revised in 2013, total organic carbon(TOC) was added as an indicative parameter for organic matter in Water and Aquatic Ecosystem Environmental Criteria. Under these imminent circumstances, a regulatory standard is needed to achieve the proposed TOC limitation control water quality from the public sewage treatment plants(PSTWs). This study purposes to present the determination method for TOC effluent limitation at the PSTWs. Therefore we investigate the TOC effluent limitation of foreign countries such as EU, Germany and USA, and analyse the effluent water qualities of PSTWs. In using these TOC data, we review apprehensively the statistics-based, the technology-based, and the region(water quality)-based determination method of TOC effluent limitation for PSTWs.

The purpose of this paper is to analyze the problems and the sources of defective products and draw improvement plans in a small plastic boat manufacturing process using TOC (Theory Of Constraints) and statistical analysis. TOC is a methodology to present a scheme for optimization of production process by finding the CCR (Capacity Constraints Resource) in the organization or the all production process through the concentration improvement activity. In this paper, we found and reformed constraints and bottlenecks in plastic boat manufacturing process in the target company for less defect ratio and production cost by applying DBR (Drum, Buffer, Rope) scheduling. And we set the threshold values for the critical process variables using statistical analysis. The result can be summarized as follows. First, CCRs in inventory control, material mix, and oven setting were found and solutions were suggested by applying DBR method. Second, the logical thinking process was utilized to find core conflict factors and draw solutions. Third, to specify the solution plan, experiment data were statistically analyzed. Data were collected from the daily journal addressing the details of 96 products such as temperature, humidity, duration and temperature of heating process, rotation speed, duration time of cooling, and the temperature of removal process. Basic statistics and logistic regression analysis were conducted with the defection as the dependent variable. Finally, critical values for major processes were proposed based on the analysis. This paper has a practical importance in contribution to the quality level of the target company through theoretical approach, TOC, and statistical analysis. However, limited number of data might depreciate the significance of the analysis and therefore it will be interesting further research direction to specify the significant manufacturing conditions across different products and processes.

Under Korea’s Enforcement Decree of the Framework Act on Environmental Policy amended in 2013, total organic carbon (TOC) is newly added as water quality parameter to assess organic pollution in the aquatic ecosystem. To meet the TOC requirement and improve quality of effluent discharged into public watershed, it is also necessary to develop standards for TOC in effluent from public sewage treatment works (PSTWs).In this study, we reviewed the characteristics and removal efficiency of TOC in influent and effluent of PSTWs. The study found that phosphorus treatment process removed not only soluble phosphorus but also a portion of TOC remaining after the secondary treatment process. TOC concentration in effluent from PSTWs operated in tandem with industrial wastewater treatment work was higher due to influx of insoluble substances from the industrial wastewater treatment work.In order to lay a foundation for the management of TOC from PSTWs, it is necessary to carry out research on TOC from different perspectives. For example, studies on the generation mechanism of TOC and the impact of TOC on drinking water resources, assessment of effluent qualities through monitoring, and development of measures to control TOC for the preservation of aquatic ecosystem are needed.

Recently, paradox management is a new paradigm to solve the management dilemmas. This is a new perspective and a creative way of thinking to draw the synergic effect by pursuing simultaneously the conflicting elements. As one method for the paradox manage

This paper was concerned about case study for preventing WMDSs(Work-related Musculoskeletal Disorders) by using Thinking Process of TOC(Theory Of Constraints), Unfortunately, the number of WMDSs are rising steadily in auto-part manufacturer. These WMDSs have on worse and worse influence not only on the competition of enterprise but on the life quality of a worker. The research results are helpful to establish the preventing WMDSs and improvement of workplace environments for small-medium sized auto-part company.

The TOC and Six Sigma are the most attention-getting concepts for managing manufacturing companies. Using the ideas and methods of the TOC, companies can achieve a large reduction of work-in-process and finished good inventories, significant improvement in scheduling performance, and substantial earnings increase. The six sigma approach derives the overall process of selecting the right project based on their potential to improve performance metrics and selecting and training the right people to get the business results. These two concepts have different backgrounds and different viewpoints for production systems. so, if the two concepts integrate each other, the synergy effects to innovate production systems can be expected. The purpose of this paper suggest that integration strategy between Six Sigma and TOC for profit maximization.

Even though Companies have used to focus on maximizing the facility rates of operation to enhance their competitiveness and increasing employees' productivity to accomplish the price and quality control, they no longer can make their business successful in these days. To be successful in increasingly competitive environment, it is essential to capture customers' needs and to reflect customers' needs in their production scheduling system. This paper describes that manufacturing scheduling method using TOC in SCM environment to change companies-oriented manufacturing scheduling to customer-oriented manufacturing scheduling.

TOC는 90년대 후반부터 경영혁신의 방법론으로 크게 부각되어 다방면으로 활발한 연구가 진행되고 있다. 그 중에서도 DBR이론은 기존의 다른 생산시스템보다 생산현장에 발생할 수 있는 문제에 쉽게 접근하고 해결할 수 있는 방법을 제시하고 있어서 산업현장에서 적용하기 위한 많은 노력을 기울이고 있다. 그러나 쉽게 이해할 수 있는 이론에 비해 현장에 직접 적용하는 과정에 있어서는 방법론에 대한 해석이 부족하고 전문적 노하우를 통한 체계적 방법부터 연구할 필요성이 대두되고 있어서 최근의 DBR 연구추세는 6시그마나 간판방식 등과 결합되어 새롭게 해석된 방법론들이 제시되고 있다. 본 논문에서는 간판방식을 응용하여 DBR 시스템을 활용하는 방법에 관해 연구하였으며 특히 DBR의 핵심요소 중 하나인 Buffer 관리를 쉽게 접근할 수 있는 방법에 관해 제시하고자 한다

Companies adopted a program called Six Sigma, in order to make fundamental changes in the way the company operated to fulfill customers' expectations. Six Sigma reduces the occurrence of defects. This approach derives the overall process of selection the

Companies adopted a program called Six Sigma, in order to make fundamental changes in the way the company operated to fulfill customers' expectations. Six Sigma reduces the occurrence of defects. However, in the course of Six Sigma process steps, companies are in the face of problems. This study is to solve the problems using TOC(Theory of Constrains). As a specific case, we review Six sigma's Define phrase. We apply TP(Thinking Process) of Toc for Define Phrase.

TOC(Theory Of Constraints) has been applied to manufacturing field traditionally. Nowadays, it's area is being wide to SCM, Service, Marketing. This paper analyzed Demand pull Manufacturing system, then, tried to apply TOC concept for improving productivity. It used DBR (Drum-Buffer-Rope) considering defect and OEE (Overall Equipment Efficiency) . For illustration, simulation was showed and it is suggested how to do for productivity improvement.