• 전자공학회논문지S
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• 제35S권2호
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• pp.137-145
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• 1998

In this paper, we propose a tube-hole center detection vision algorithm verifying the position of a tele-controlled robot and providing visual information for increasing reliability and efficiency in the diagnosis of steam generator (SG) tubes in nuclear power plant. A tele-controlled robot plays a role in carrying the probe used in inspecting the integrity of SG tubes. Thus accurately locating a tele-controlled robot on the desired tube-hole center is important issue for reliability of inspection. To do this work, we have to find the tube-hole center locations from the input image. At first, we apply the three-class segmentation method modified for this application. WE extract minimum bounding rectangles (MBRs) in the theresholded binary image. Second, for discriminating between MBR by tube and MBR by noise, we introduce the MBR rejection rules as knowledge-based rule set. MBRs are divided into the very dark region MBRs and the very bright region MBRs. In order to describe the region of complete tube-hole, the MBRs need a process of pairing each other. We then can find the tube-hole center from the paired MBR. For more accurately finding the tube-hole center in several sequential images, the centers of some frames need to be averaged. We tested the performance of our method using hundreds of real images.

• Membrane and Water Treatment
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• 제6권3호
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• pp.189-203
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• 2015

Membrane biofouling impedes wide application of membrane bioreactor (MBR) for wastewater treatment. Recently, quorum sensing (QS) mechanisms are accounted for one of major mechanisms in biofouling of MBRs. In this study, vanillin was applied to investigate reduction of biofouling in MBRs. MBR sludge was analyzed to contain QS signal molecules by cross-feeding biosensor assay and HPLC. In addition, the inhibitory activity of vanillin against bacterial quorum sensing was verified using an indicator strain CV026. The vanillin doses greater than 125 mg/L to 100 mL of MBR sludge showed 25% reduction of biofilm formed on the membrane surfaces. Two MBRs, i.e., a typical MBR as a control and an MBR with vanillin, were operated. The TMP increases of the control MBR were more rapid compared to those of the MBR with the vanillin dose of 250 mg/L. The treatment efficiencies of the two MBRs on organic removal and MLSS were maintained relatively constant. Extracellular polymeric substance concentrations measured at the end of the MBR operation were 173 mg/g biocake for the control MBR and 119 mg/g biocake for the MBR with vanillin. Vanillin shows great potential as an anti-biofouling agent for MBRs without any interference on microbial activity for wastewater treatment.

• Journal of Microbiology and Biotechnology
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• 제26권9호
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• pp.1593-1604
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• 2016

Recently, bacterial quorum quenching (QQ) has been proven to have potential as an innovative approach for biofouling control in membrane bioreactors (MBRs) for advanced wastewater treatment. Although information regarding the microbial community is crucial for the development of QQ strategies, little information exists on the microbial ecology in QQ-MBRs. In this study, the microbial communities of biofilm were investigated in relation to the effect of QQ on anoxic/oxic MBRs. Two laboratory-scale MBRs were operated with and without QQ-beads (QQ-bacteria entrapped in beads). The transmembrane pressure increase in the QQ-MBRs was delayed by approximately 100-110% compared with conventional- and vacant-MBRs (beads without QQ-bacteria) at 45 kPa. In terms of the microbial community, QQ gradually favored the development of a diverse and even community. QQ had an effect on both the bacterial composition and change rate of the bacterial composition. Proteobacteria and Bacteroidetes were the most dominant phyla in the biofilm, and the average relative composition of Proteobacteria was low in the QQ-MBR. Thiothrix sp. was the dominant bacterium in the biofilm. The relative composition of Thiothrix sp. was low in the QQ-MBR. These findings provide useful information that can inform the development of a new QQ strategy.

• 상하수도학회지
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• 제30권5호
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• pp.545-551
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• 2016

This study compares characteristic of membrane fouling in MBR-RO systems. In lab. scale MBRs test, MBRs were operated at different Flux(10, 20, 30 & 40 LMH) and temperature(10, 15, 20, 25 & $30^{\circ}C$). The results show that MBR permeate was measured lower amounts of organic substances in Higher flux and lower temperature and led to lower RO fouling rates. The main cause was that due to cake fouling formed on membrane surfaces in MBRs. Under both cases, Cake layer of membrane surfaces formed in MBRs removed RO fouling factors, polysaccharide and protein, because of cake layer attached on membrane surfaces greater amounts of organic substances. This study implies that optimization of MBR with operating conditions is a crucial strategy to RO membrane fouling control.

• Membrane and Water Treatment
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• 제3권1호
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• pp.1-23
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• 2012

The coupling of anaerobic biological process and membrane separation could provide excellent suspended solids removal and better biomass retention for wastewater treatment. This coupling improves the biological treatment process while allowing for the recovery of energy through biogas. This review gives a basic description of the anaerobic wastewater treatment process, summarizes the state of the art of anaerobic membrane bioreactors (AnMBRs), and describes the current research trends and needs for the development of AnMBRs. The research interest on AnMBR has grown over the conventional anaerobic processes such as upflow anaerobic sludge blanket (UASB). Studies on AnMBRs have developed different reactor configurations to enhance performances. The AnMBR performances have achieved comparable status to other high rate anaerobic reactors. AnMBR is highly suitable for application with thermophilic anaerobic process to enhance performances. Studies indicate that the applications of AnMBR are not only limited to the high strength industrial wastewater treatment, but also for the municipal wastewater treatment. In recent years, there is a significant progress in the membrane fouling studies, which is a major concern in AnMBR application.

• 멤브레인
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• 제23권1호
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• pp.24-44
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• 2013

MBR 기술은 지난 20여 년 동안 처리성능과 효율성 그리고 비용절감 측면에서 빠른 속도로 발전하고 있다. 또한 안정적인 하수처리와 하수재이용관점에서 핵심기술로 널리 인식되고 있다. 본고에서는 MBR 기술의 개발과 상업적 응용에 관한 발전과정을 재조명하고 세계 시장의 전망을 제시하고자 한다. 주요 적용기술에 대해 다음 5가지 측면에서 검토하여 제시하였는데 1) MBR 기술의 진화, 2) MRBs의 상업용 기술, 3) 대용량 MBR 플랜트 설치 사례, 4) MBR 시장의 성장, 5) 기술의 발전방향 순으로 제시하였다. 마지막으로 MBRs에 대한 경제적, 환경적, 그리고 기술적 측면에서 향후 발전방향을 1) 초기투자비, 2) 처리 수질, 3) 분리막 소재/모듈, 4) MBR 장비와 공정, 5) 운영비용, 향후 6) 혐기성 MBRs 공정과 같은 차세대 기술 분야로 나누어 제시하였다.

• 음성과학
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• 제12권3호
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• pp.35-48
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• 2005

This study was to examine the relationship between maternal interactive behaviors and stuttering behaviors in preschool children who stutter. Participants were twenty-four children who stutter and their mothers. For the purpose of the current study, 5$\sim$10 minutes of 50 minutes videotaped scenes originally collected to develop fluency assessment instrument were re-videotaped. They included mother-child interactions during playing with toys and reading book situations. Mothers-children interactive behaviors were assessed with Maternal Behavior Rating Sroles(MBRS) and Child Behavior Rating Scales (CBRS). And children's stuttering were assessed with Paradise-Fluency Assessment(P-FA). The results were as follows: 1) the maternal interactive behavior did not significantly differ depending on situations, but scores of maternal responsive factor were higher in the play situation than in the reading situation. 2) Maternal responsiveness might influence on promoting the children's pivotal behavior with children who stutter. And 3) the level of maternal responsiveness was the predictor of children's stuttering behaviors. The therapeutic implication of the results were discussed.

• Journal of Mechanical Science and Technology
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• 제18권6호
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• pp.946-954
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• 2004

A model in the form of a Bearing Load Distribution (BLD) matrix in the Multi Bearing Rotor System (MBRS) is established by a transfer matrix equation with the consideration of a bearing load, elevation and uniform load distribution. The concept of Bearing Load Sensitivity (BLS) is proposed and matrices for load and elevation sensitivity are obtained. In order to share MBRS design resources on the Internet with remote customers, the basic principle of Remote Computing (RC) based on the Internet is introduced ; the RC of the BLD and BLS is achieved by Microsoft Active Server Pages (ASP) technology.

• 멤브레인
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• 제25권3호
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• pp.276-286
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• 2015

30 LMH의 정유량 플럭스로 운전하는 MBR에서, 휴지 및 역세정에 따른 한외여과 분리막의 오염을 조사하였다. 또한, 연속적인 공기세정과 비교하여 분리막 여과저항을 최소화하기 위한 간헐적인 공기세정을 평가하였다. 여과 조건은 14.5분 여과와 0.5분의 휴지를 유지하였으며, 역세정 시간은 휴지 시간과 동일하게 운전하였다. 공기세정이 정지하는 동안에 분리막 표면의 겔층 위에 케?이 빠르게 축척되었으며, 역세정으로 겔층과 케?층의 복합층은 쉽게 제거되었다. 역세정 후에 공기세정이 정지하는 동안 분리막 표면에 케?이 형성되어 공경 내부의 오염현상을 억제하였다. Pearson 상관성을 조사한 결과, 간헐적인 공기세정에서 공기 세정이 정지하는 시간과 분리막의 오염은 매우 연관성이 높다는 것을 알았다. 즉, 간헐적인 세정에서 공기세정이 정지하는 시간이 갈수록 오염억제에 효과적이었다.

• 상하수도학회지
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• 제30권5호
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• pp.605-612
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• 2016

Membrane bioreactors (MBRs) employ a process of biological treatment that is based on a membrane that has the advantages of producing high-quality treated water and possessing a compact footprint. However, despite these advantages, the occurrence of "fouling" during the operation of these reactors causes the difficulty of maintenance. Hence, in this study, three physical cleaning methods, namely, backwashing, air scrubbing, and mechanical cleaning ball was performed to identify optimum operating conditions through laboratory scale experiments, and apply them in a pilot plant. Further, the existing MBR process was compared with these methods, and the field applicability of a combination of these physical cleaning methods was investigated. Consequently, MCB, direct control of cake fouling on the membrane surface was found to be the most effective. Moreover, as a result of operating with combination of the physical cleaning process in a pilot plant, the TMP increasing rate was found to be - 0.00007 MPa/day, which was 185% higher than that obtained using the existing MBR process. Therefore, assuming fouling only by cake filtration, about one year of operation without chemical cleaning is considered to be feasible through the optimization of the physical cleaning methods.