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        검색결과 39

        1.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        고분자 분리막의 대표적인 형태 중 하나인 평판형 분리막은 제조가 용이하여 실험실에서 분리막 소재 연구에서부 터 실제 상용 분리막 생산에 이르기까지 널리 활용되는 분리막의 형태이다. 정밀여과 및 한외여과 등에 사용되는 평판형의 다공성 고분자 분리막은 주로 상분리 공정을 통해 제조할 수 있으며, 여기에는 비용매 유도 및 증기 유도 상분리 공정이 활 용된다. 그러나 상분리 공정 특성상 주변 환경과 실험자에 따라 샘플 간 편차가 쉽게 발생하여 재현성의 확보가 어려운 점이 있다. 따라서 개발된 제조기술을 스케일업 및 재현성 확보를 위해 제어된 환경에서 연속식 대면적 제조가 가능한 롤투롤 제 조장치가 필요하며, 본 연구에서는 실험실 스케일의 제조기술을 나이프 및 슬롯다이 롤투롤 공정으로 스케일 업 했을 때 나 타나는 제조 환경 차이에 따른 분리막의 특성 변화를 비교하였다. 최종적으로 연속식 제조공정 인자에 대한 최적화를 통해 대면적 제조 시 분리막의 균일성을 확보하였다.
        4,000원
        5.
        2023.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        In probiotics production, lactic acid bacteria (LAB) are cultured on a large scale to achieve efficient processing through fermentation optimization and scale-up. In this Current study, the LAB strain Lactiplantibacillus plantarum WiKim0125 was isolated from kimchi and optimized the production. The optimization strategy for cultivating L. plantarum WiKim0125 consisted of investigating media components, selecting physiochemical conditions to enhance productivity, and scaling up for pilot-scale production. Each process condition was evaluated based on substrate consumption, lactic acid production, and viable cell yield. As a result, the final viable cell and lactic acid yield of L. plantarum WiKim0125 increased by 38.6% and 19.4%, respectively. This study provides an overview of fermentation optimization and scale-up processes for the industrial application of L. plantarum WiKim0125.
        4,000원
        6.
        2022.10 구독 인증기관·개인회원 무료
        Decommissioning waste is generated at all stages during the decommissioning of nuclear facilities, and various types of radioactive waste are generated in large quantities within a short period. Concrete is a major building material for nuclear facilities. It is mixed with aggregate, sand, and cement with water by the relevant mixing ratio and dried for a certain period. Currently, the proposed treatment method for volume reduction of radioactive concrete waste was involved thermomechanical and chemical treatment sequentially. The aggregate as non-radioactive materials is separated from cement components as contaminated sources of radionuclides. However, to commercialize the process established in the laboratory, it is necessary to evaluate the scale-up potential by using the unit equipment. In this study, bench-scale testing was performed to evaluate the scale-up properties of the thermomechanical and chemical treatment process, which consisted of three stages (1: Thermomechanical treatment, 2: Chemical treatment, 3: Wastewater treatment). In the first stage, lab, bench, and pilot scale thermomechanical tests were performed to evaluate the treated coarse aggregate and fines. In the second stage, the fine particles generated by the thermomechanical treatment process, were chemically treated using dissolution equipment, after then the removal efficiency and residual of cement in the small aggregate was compared with laboratory results. The final stage, the secondary wastewater containing contaminant nuclides was treated, and the contaminant nuclides could be removed by chemical precipitation method in the scale-up reactors. Furthermore, an additional study was required on the solid-liquid separation, which connected each part of the equipment. It was conducted to optimize the separation method for the characteristics of the particles to be separated and the purpose of separation. Therefore, it is expected that the basic engineering data for commercialization was collected by this study.
        11.
        2018.11 구독 인증기관·개인회원 무료
        Although thin-film nanocomposite membranes (TFNs) have paved the way to develop high-performance reverse osmosis (RO) membranes, scale-up production of TFNs is still challenging issue. Herein, we introduced a novel preparation method for TFNs using spray-assisted nanofiller pre-deposition (Spray method) to circumvent the limitations in conventional method. The precise control of nanofiller (ZIF-8) loading was possible by simply varying the spraying ZIF-8 concentration. Most importantly, TFNs prepared by both Spray and conventional method showed similar RO performances, while Spray method only requires ~100 times minimized amount of ZIF-8 with an unprecedentedly short deposition time (< 1 min) ever reported. Our results revealed that Spray method would be promising for the scale-up of TFNs in terms of cost, time, and controllability.
        12.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The lack of seed sludges for Ammonium Oxidizing Bacteria (AOB) and slow-growing ANaerobic AMMonium OXidation (ANAMMOX) bacteria is one of the major problem for large-scale application. In this study, 24m3 of single-stage SBR (Sequencing Batch Reactor) was operated to remove nitrogen from reject water using AOB and ANAMMOX bacteria cultivated from activated sludge in the field. The ANAMMOX activity was found after 44 days of cultivation in the ANAMMOX cultivation reactor, and then 0.66 kg N/m3/d of the nitrogen removal rate was achieved at 0.78 kg N/m3/d of the nitrogen loading rate at 153 days of cultivation. The AOB cultivation reactor showed 0.2 kg N/m3/d of nitrite production rate at 0.4 kg N/m3/d of nitrogen loading rate after 36 days of operation. The cultivated ANAMMOX bacteria and AOB was mixed into the single-stage SBR. The feed distribution was applied to remove total nitrogen stably in the single-stage SBR. The nitrogen removal rate in the single-stage SBR was gradually enhanced with an increase of specific activities of both AOB and ANAMMOX bacteria by showing 0.49 kg N/m3/d of the nitrogen removal rate at 0.56 kg N/m3/d of the nitrogen loading rate at 54 days of operation.
        4,000원
        13.
        2017.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fish skin peptide-loaded liposomes were prepared in 100 mL and 1 L solution as lab scales, and 10 L solution as a prototype scale. The particle size and zeta potential were measured to determine the optimal conditions for the production of fish skin peptide-loaded liposome. The liposome was manufactured by the following conditions: (1) primary homogenization at 4,000 rpm, 8,000 rpm, and 12,000 rpm for 3 minutes; (2) secondary homogenization at 40 watt (W), 60 W, and 80 W for 3 minutes. From this experimental design, the optimal conditions of homogenization were selected as 4,000 rpm and 60 W. For the next step, fish peptides were prepared as the concentrations of 3, 6, and 12% at the optimum manufacturing conditions of liposome and stored at 4ºC. Particle size, polydispersion index (pdI), and zeta potential of peptide-loaded liposome were measured for its stability. Particle size increased significantly as manufacture scale and peptide concentration increased, and decreased over storage time. The zeta potential results increased as storage time increased at 10 L scale. In addition, 12% peptide showed the formation of a sediment layer after 3 weeks, and 6% peptide was considered to be the most suitable for industrial application.
        4,000원
        14.
        2017.11 구독 인증기관·개인회원 무료
        최근 정삼투 기술 연구는 정삼투막 물질이동, 다양한 분야 적용과 관련된 연구가 주로 수행되었다. 정삼투 공정 실용화를 위해서는 공정설계와 관련 된 파일럿 규모 연구가 추가적으로 필요하다. 본 연구에서는 평판형 정삼투 모듈을 이용하여 운전조건(유도용액 및 유입수 유량과 농도, 모듈 개수)에 따른 모듈 성 능을 분석하고, 이를 바탕으로 정삼투 공정 설계 방안을 제시하고자 하였다. 직렬로 연결된 평막 모듈의 개수가 증가함에 따라 운전압력이 증가하였으나, 나권 형 모듈에 비해 압력 증가량이 낮아 평막 모듈 형태가 정삼투 공정 스케일 업에 적합하다고 판단된다. 유입수 유량대비 막면적은 삼투압차를 근거로 예측한 회수율을 얻는 주요 인자임을 제시하였고, 이를 바탕으로 정삼투 공정설계 연구 결과를 나타내었다.
        16.
        2015.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A full-scale process has been developed to immobilize fission products that accumulate within the Mark IV electrorefiner (ER) electrolyte at Idaho National Laboratory. ER salt was blended with treatment additives, followed by pressureless consolidation (PC) in a furnace to produce a durable ceramic waste form (CWF). The goal is the development of a process to consolidate actual radioactive ER salt into a form suitable for transportation and disposal.Four batches (300 to 400 kg per batch) of full-scale pre-qualification material preparation runs have been prepared. From these four batches of nonradioactive salt-loaded surrogate material, three full-scale PC trials have been conducted. The first PC test run, established equipment parameters with a basic CWF container design. The second trial included a modified CWF container design, real-time measurement of CWF consolidation, and an audio recording to identify cracking during the CWF cool-down. During the third trial, salt was doped (from the fourth material preparation batch) to create a nonradioactive salt material and to more closely represent actual ER salt. The second and third trials were also used to validate a model developed for the CWF. The CWF model is beneficial for understanding and predicting the physical processes that occur during the heat cycle. This would be particularly useful when the CWF is located in a hot cell, which makes accessing and examining a CWF difficult.
        5,700원
        18.
        2014.10 구독 인증기관·개인회원 무료
        Methyl Bromide (MB) has been regulated by montreal protocol due to ozone depletion since 1992, and there is a need to develop MB alternative fumigation methods. To find out the efficacies and tolerance in developmental stages of citrus mealybugs (Planococcus citri) which frequently infested in imported pineapples, phosphine(PH3) gas was tested in different exposure times (2~24 hr) and concentrations (0.1∼2g/m3) in small desiccators at 8℃. Based on Lethal 99% concentration × time products (LCTP 99%) of PH3 gas to target developmental insect, 2g/m3 PH3 was applied for 24 hr in 300 m3 fumigation facility, which was designed in well sealed and evacuation system (5 air exchange/min). We monitored PH3 gas in fumigation facility to confirm CTP and checked PH3 gas in atmospheres in air ventiliation process after fumigations to make quarantine guideline and protocol for worker safety as well as efficacy to target pest.
        19.
        2014.06 구독 인증기관 무료, 개인회원 유료
        Malaysia is currently implementing the use of the Frog Virtual Learning Environment (VLE) in all government schools in the country. This paper outlines the basis for introducing the VLE in leveraging teaching and learning in Malaysian schools. It discusses the state of current literature associated with the use of VLE. In addition, it articulates the need for programme evaluation as a means for decision-makers to plan and take necessary corrective action to better implement VLE among teachers and students in schools. To sustain the implementation of this endeavour, a monitoring and evaluation mechanism must be put in place. This would determine how the VLE is performing and ascertain key success factors with the use of the Frog VLE among teachers and students. For this purpose, a survey research was undertaken using a sample comprising 426 teachers and 223 students from primary and secondary schools throughout the country. Reliability computations show Cronbach alpha values greater than .90 for the various constructs in the scaled items of the teachers’ and students’ questionnaires. The key findings of the study show significantly different perceptions (p < .05) in the use of Frog VLE as a learning tool between primary pupils and secondary students with significantly higher perceptions from secondary students on all aspects ranging from ease of use of Frog VLE to using Frog VLE as a collaborative tool for interaction within and outside the classroom. Factor analysis via the Principal Component Analysis method shows 3 critical success factors cited by teachers in the use of Frog VLE. The first factor concerns the functionality of VLE as a pedagogical tool; the second is associated with the user-friendliness of the VLE; and the third concerns the VLE as a tool for collaboration. An analysis of ranks derived from the mean computations of the variables within the first factor shows the VLE provides a platform for teachers to share ideas and opinions being ranked first. This is followed by VLE being used by students to obtain learning materials, which is ranked second. Third, the VLE being used by teachers to source for new teaching materials. Other major findings include issues associated with slow and unstable internet connectivity where secondary schools fared worse compared to primary schools and that rural schools tended to have more problems in connectivity as compared to urban schools. This paper puts forth a proposition that educational technology needs continuous monitoring and evaluation and effective change management is imperative to attain success in its implementation.
        5,100원
        20.
        2011.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Balance is a complex motor skill that depends on interactions between multiple sensorimotor processes and environmental and functional contexts. Many rehabilitation specialists believe that balance assessment under multitask conditions may be a more sensitive indicator of balance problems and falls than balance assessment in a single-task context. Functional Gait Assessment has many tasks that allow for testing under multitask conditions. The purpose of this study was to determine the concurrent validity between the Functional Gait Assessment (FGA), Berg Balance Scale (BBS), and Timed "Up & Go" Test (TUG) in patients with stroke. One hundred and five participants with at least 3 months post stroke and able to walk at least 6 m with or without a mono cane, participated in this study. Concurrent validity between the FGA, BBS, and TUG was assessed using Spearman rank order correlation. The FGA correlated with the BBS (r=.80, p<.01) and TUG (r=-.77, p<.01). The good and moderate correlation between the FGA, BBS, and TUG establishes the concurrent validity of the FGA in patients with stroke. These measures provide clinicians with valuable information about patients' functional balance capabilities.
        4,000원
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