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        검색결과 9

        2.
        2023.11 구독 인증기관·개인회원 무료
        Pyroprocessing technology has emerged as a viable alternative for the treatment of metal/oxide used fuel within the nuclear fuel cycle. This innovative approach involves an oxide reduction process wherein spent fuel in oxide form is placed within a cathode basket immersed in a molten LiCl-Li2O salt operating at 923 K. The chemical reduction of these oxide materials into their metallic counterparts occurs through a reaction with Li metal, which is electrochemically deposited onto the cathode. However, during process, the generation of Li2O within the fuel basket is inevitable, and due to the limited reduction efficiency, a significant portion of rare earth oxides (REOx) remains in their oxide state. The presence of these impurities, specifically Li2O and REOx, necessitates their transfer into the electrorefining system, leading to several challenges. Both Li2O and REOx exhibit reactivity with UCl3, the primary electrolyte within the electrorefining system, causing a continuous reduction in UCl3 concentration throughout the process. Furthermore, the formation of fine UO2 powder within the salt system, resulting from chemical reactions, poses a potential long-term operational and safety concern within the electrorefining process.Various techniques have been developed to address the issue of UO2 fine particle removal from the salt, utilizing both chemical and mechanical methods. However, it is crucial that these methods do not interfere with the core pyroprocessing procedure. This study aims to investigate the impact of Li2O and REOx introduced from the electrolytic reduction process on the electrorefining system. Additionally, we propose a method to effectively eliminate the generated UO2 fine powder, thereby enhancing the long-term operational stability of the electrorefining process. The efficiency of this proposed solution in removing oxidized powder has been confirmed through laboratory-scale testing, and we will provide a comprehensive discussion of the detailed results.
        3.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Membrane filtration process is an advanced water treatment technology that has excellently removes turbidity and microorganisms. However, it is known that it has problems such as low economic efficiency and the operating stability. Therefore, this study was to evaluate on the economical feasibility and operational stability comparison of membrane and sand filtration process in Im-sil drinking water treatment plant. For the economic analysis of each process, the electricity cost and chemical consumption were compared. In the case of electric power consumption, electricity cost is 68.67KRW/㎥ for sand filtration and 79.98KRW/㎥ for membrane filtration, respectively. Therefore, membrane filtration process was about 16% higher than sand filtration process of electricity cost. While, the coagulant usage in the membrane filtration process was 43% lower than the sand filtration process. Thus, comparing the operation costs of the two processes, there is no significant difference in the operating cost of the membrane filtration process and the sand filtration process as 85.94KRW/m3 and 79.71KRW/m3 respectively (the sum of electricity and chemical cost). As a result of operating the membrane filtration process for 3 years including the winter season and the high turbidity period, the filtrated water turbidity was stable to less than 0.025 NTU irrespective of changes in the turbidity of raw water. And the CIP(Clean In Place) cycle turned out to be more than 1 year. Based on the results of this study, the membrane filtration process showed high performance of water quality, and it was also determined to have the economics and operation stability.
        4,000원
        4.
        2012.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: Regional offices of the Ministry of Land, Transport and Maritime Affairs use a computerized system called KAMIS so as to manage road equipment systematically. Road agencies can record number of operating days by equipment, actual working hours, accumulated operating hours (or distance) by equipment, and operating cost. However, KAMIS does not provide critical information, although it is strongly related to efficient road management equipment operation. In other words, road agencies do not know whether they have sufficient equipment to handle their actual work. METHODS: Therefore, this study suggests a methodology to evaluate for operational efficiency of road management equipment using analytical hierarchy process(AHP). First of all, estimated weights related criteria can be produced by AHP, and then use operational history by pieces of equipment. RESULTS: Results show that importance of management work can differ from weather conditions through five areas. CONCLUSIONS: Commonly, this results can imply to help save money for the purchase and maintenance of road management equipment, and they would improve the functional performance of KAMIS.
        4,000원
        5.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        온대저기압화는 중위도 기압계에 큰 영향을 주고 때로는 악기상의 원인이 되기도 한다. 그러나 온대저기압화에 대한 예보와 연구 양쪽 모두 많은 과제가 남아있다. 왜냐하면 태풍으로부터 변질된 온대저기압 자체의 모호한 형태 때문이다. 또한, 온대저기압화의 정의가 예보나 연구 양쪽 모두 만족시켜줄 만큼 정확하지도 않다 따라서 기상청은 2007 년에 "온대저기압화 현엽매뉴얼"을 개발하여 온대저기압화의 일련의 과정과 구조 변화 진단에 사용하였다. 이 매뉴얼에서는 1단계 최대풍속과 해수면온도, 2단계 위성영상, 3단계 단열선도, 그리고 최종단계인 4단계에서 지상일기도를 분석하였다. 이 현업매뉴얼은 온대저기압화가 일어날 때 구조변화의 이해와 감시에 도움이 될 것이다.
        4,300원
        6.
        2007.02 구독 인증기관 무료, 개인회원 유료
        To improve water quality of Buji Stream and Shenzhen River, the Bujihe Wastewater Treatment Plant has been reconstructed from the original coagulkation-flocculation sedimentation system into the enhanced hybrid submerged biofilm-activated sludge (EHYBFAS)system developed by the authors. The main design parameters of the EHYBFAS system, process characteristics, operational performance, techno-economic index, and experience in design, construction and operation are described,which set up an example of the municipal wastewater treatment plants using the novel process of EHYBFAS, which has lots of advantages, such as stable and high operational performance with the final effluent quality well meeting 1A-1B standard of GB 18918-2002( Chinese national standard for pollutants of effluent from the MWWTPs), much less footprint of 1ha/(100×103m3/d)) vs 4-5ha/(100×103m3/d), much lower capital and operation costs of 700-800 Yuan(RMB)/(m3/d) and 0.5 Yuan(RMB)/m3 vs 1200-1500 Yuan/(m3/d)and 1.0-1.2 Yuan/m3 and much less sludge production of 0.3g dry solid/g removed BOD5 vs 0.7 g dry solid/removed BOD5 respectively for the MWWTP with AS process.
        5,100원
        7.
        2022.04 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study was to evaluate the operational characteristics of wastewater treatment using Sequencing Batch Reactor (SBR) with Aerobic Granular Sludge (AGS) separator in the pilot plant. Pilot plant experiments were conducted using SBR with AGS separator and pollution removal efficiencies were evaluated based on the operational condition and surface properties of AGS. The results of the operation on water quality of the effluent showed that the average concentration of total organic carbon, suspended solids, nitrogen, and phosphorus was 6.89 mg/L, 7.33 mg/L, 7.33 mg/L, and 0.2 mg/L, respectively. All these concentrations complied the effluent standard in Korea. The concentration of mixed liquor suspended solid (MLSS) fluctuated, but the AGS/MLSS ratio was constant at 86.5±1.3%. Although the AGS/MLSS ratio was constant, sludge volume index improved. These results suggested that the particle discharged fine sludge and increased the AGS praticle size in the AGS. Optical microscopy revealed the presence of dense AGS at the end of the operation, and particles of > 0.6 mm were found. Compared to those of belt-type AGS separator, the required area and power consumption of the hydrocyclone-type AGS separator were reduced by 27.5% and 83.8%, respectively.
        8.
        2016.10 KCI 등재 서비스 종료(열람 제한)
        Despite the low removal efficiencies reported by previous studies, electro-flotation still stands out among other microalgae removal methods for its economical and environmental benefits. To enhance removal efficiency, the important factors that limit the performance of this method must be investigated. In this study, the possible ways of increasing the removal efficiency of microalgae have been explored by investigating the effects of several important variables in electro-flotation. Eight parameters, namely flotation time, rising time, current density, pH, conductivity, electrode distance, temperature and initial concentration were evaluated using a one-parameter-at-a-time approach. Results revealed that the operational parameters that greatly affected the removal efficiency of microalgae were electro-flotation time, current density, pH, and initial concentration. The effect of conductivity, electrode distance, and temperature on removal efficiency were insignificant. However, they exhibited positive an indirect positive effect on power demand, which is nowadays considered an equally important aspect in the running of a feasible and economically efficient electro-flotation process.
        9.
        2007.03 KCI 등재 서비스 종료(열람 제한)
        The purpose of this research was to investigate and analyse how Community Forest Initiatives as urban fringe management initiatives made alliances with a variety of interest groups, enrol them in the urban fringe management processes using the Actor Network Theory. The Thames Chase Community Forest Initiative was selected and its area of operation included a 97 km2 area of green-belt area in East London. It was a instrument far improving and protecting the unique characteristics of the countryside landscape from urban developments as well as evaluating the impact of forestry inclusion in land use planning in the urban fringe. It was operated through a tiered structure comprising the Thames Chase Joint Committee and the management team. They employed a variety of devices to speak with one voice to bring about an effective operation process and to secure the enrolment of a variety of interest groups in its operational processes. Of note, the initiative's actor network impacted on improvement to and management of the countryside landscape despite not owning any land itself. As a result, when urban fringe management initiatives will be launched in South Korea to achieve a more effective and efficient urban fringe management, local councillors and representatives from public and non-government bodies should be more responsive to local communities' views and needs and work more vigorously on their behalf through lobbying, seeking media support, and so on. Moreover, better understanding and communication between local authorities' officers and management initiatives' teams are essential to avoid duplication of work practice.