• 제목/요약/키워드: micro bubbles

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지능정보기술과 민주주의: 알고리즘 정보환경과 정치의 문제 (Intelligent Information Technology and Democracy : Algorithm-driven Information Environment and Politics)

  • 민희;김정연
    • 정보화정책
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    • 제26권2호
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    • pp.81-95
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    • 2019
  • 최근 선거캠페인에서 수집되는 유권자 모델링 및 맞춤형 커뮤니케이션에 관한 데이터는 양적 확장성과 질적 유용성 측면에서 새롭다. 본 연구는 지능정보기술을 활용한 고도의 데이터 분석 능력이 정치에 어떻게 활용되고 있는지에 주목한다. 그 중에서도 선거캠페인에서의 유권자 행동 타게팅이 다양한 측면에서 민주주의 과정과 충돌할 수 있다는 점에 초점을 맞춘다. 이를 위해 마이크로 타게팅과 정치 봇을 살펴본다. 본 연구는 이러한 기술 기반의 캠페인 기법들이 민주주의의 핵심인 자유로운 의견 표출과 논쟁을 방해하는 요인으로 작동하는 양상을 보여준다. 동시에 이에 영향을 미치는 알고리즘의 속성을 파악한다. 본 연구는 지능정보기술 기반의 정치와 민주주의에서 다음과 같은 문제가 발생할 수 있음을 제시한다. 첫째, 정치참여의 불평등이 심화된다. 둘째, 유권자 간 공적 논쟁이 어려워진다. 셋째, 피상적인 정치가 만연한다. 넷째, 단일 이슈 정치와 배제의 정치 현상이 증가한다. 마지막으로 정치적 프라이버시가 침해될 수 있다. 요컨대, 지능정보시대 우리의 역할은 점점 고도화되고 있는 지능정보기술과 민주주의가 공존할 수 있는 방법을 모색하는 것이다.

침액식 세정설비의 마이크로버블을 이용한 철강산업 공정의 산세조 발생 염화수소 제거 (Hydrochloric Acid Gas Removal from Iron and Steel Industry Using Micro-bubbles of a Dip Injection Wet Scrubber System)

  • 김예진;정재억;정용준
    • 한국습지학회지
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    • 제17권1호
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    • pp.75-79
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    • 2015
  • 대기오염물질인 염화수소의 배출 규제가 2ppm으로 강화됨에 따라 기존의 제철공장 습식세정 장치에 DIWS 시스템이 도입되었다. 침액식 스크러버 시스템으로 제철공정에서 발생되는 염화수소를 처리하기 위한 파일럿 연구를 수행하였다. DIWS 시스템의 운전에 따른 응축수 pH는 연돌에서 6.0으로 증가하였다. 산세 Fume 정제설비의 평균 유입 염화수소는 13.3ppm, 평균 배출가스는 0.43ppm, 평균 제거율은 96.9%로 나타났다. TMS 장치로 장기간 측정한 데이터를 비교하였을 때 DIWS 장치는 안정적인 제거율을 나타냈지만, TMS의 type별 데이터 불균일 현상이 관찰되었다.

Flotation of cyanobacterial particles without chemical coagulant under auto-flocculation

  • Kwak, Dong-Heui;Kim, Tae-Geum;Kim, Mi-Sug
    • Membrane and Water Treatment
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    • 제9권6호
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    • pp.447-454
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    • 2018
  • Although flotation techniques are often used for the removal of algal particles, the practicality of algae-harvesting technologies is limited owing to the complex and expensive facilities and equipment required for chemical coagulation. Here, we examined the feasibility of an approach to separating algal particles from water bodies without the need for chemical coagulants, depending on the condition of the algae, and to determine the optimal conditions. Using Anabaena sp., a cyanobacterium causes algal blooms in lakes, we stimulated auto-flocculation in algal particles without coagulants and conducted solid-liquid separation experiments of algal particles under various conditions. The six cultivation columns included in our analysis comprised four factors: Water temperature, light intensity, nutrients, and carbon source; auto-flocculation was induced under all treatments, with the exception of the treatment involving no limits to all factors, and algal particles were well-settled under all conditions for which auto-flocculation occurred. Meanwhile, flotation removal of auto-flocculated algal particles was attained only when nutrients were blocked after algae were grown in an optimal medium. However, no significant differences were detected between the functional groups of the extracellular polymeric substances (EPSs) of floated and settled algal particles in the FT-IR peak, which can cause attachment by collision with micro-bubbles.

가스하이드레이트 산업시스템 실용화 현황 및 동향 분석 (Investigation on the Practical Use of Gas Hydrate in Gas Industry)

  • 권옥배;신창훈;박승수;한정민;이정환
    • 신재생에너지
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    • 제2권2호
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    • pp.102-107
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    • 2006
  • In Japan, research and development were undertaken on gas hydrate-side industrial processes associated with power generation system connections that may particularly be necessary to develop gas hydrated technology-based industrial systems. In so doing, data and engineering technologies useful n formulating guidelines on design of practical process were accumulated. In addition, basic research into theoretical evidence were carried out to promote and support the development of technological elements for those processes. In basic research designed to promote and support the research and development of elemental technologies, microanalyses were conducted to understand the decomposition mechanism of mixed gas hydrate. Moreover, measurement technologies that can be applied in industrial processes, such as numerical analyses and concentration measurement, were examined. Japan has developed a highly efficient gas hydrate formation process using micro-bubbles with a tubular reactor. Higher formation rate over conventional systems has been obtained by the process. As mentioned above, the technical problems were clarified and the economics were studied from a view point of the NGH technology in this study. The results can be applied for utilization and must contribute to popularization of gas hydrate production.

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AP추진제의 연소면 형성 및 전파 모델링 연구 (Modeling of burning surface growth and propagation in AP-based composite propellant combustion)

  • 정태용;김기홍;유지창;도영대;김형원;여재익
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2009년도 춘계학술대회 논문집
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    • pp.191-195
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    • 2009
  • 고체추진제가 연소될 때, 고체상에서 기체상으로의 상변화가 일어난다. 액체상과 기체상의 혼합으로 인하여 거품이 형성되는데 이를 거품층(Foam Layer) 혹은 용융층(Melting Layer)이라고 한다. 일반적으로 고체추진제가 연소될 때 생성되는 거품층의 두께는 1기압에서 약 1마이크론 정도이다. 거품층의 윗부분, 즉 액체상과 기체상 사이에는 연소면(Buring Surface)이 존재하는데, 본 연구에서는 연소면의 형성과 전파를 모사하였다. 연소면의 전파 속도는 연소율과 같다.

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수중 방전을 이용한 휴믹산 제거 (The Study on the Humic Acid Removal using Underwater Plasma Discharge)

  • 홍은정;정팔진;유승민;박준석;유승열;노태협
    • 한국물환경학회지
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    • 제28권3호
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    • pp.367-374
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    • 2012
  • A flotation process has a shorter processing time and needs less space than a sedimentation process. Dissolved air flotation process (DAF) is an efficient flotation method and used in a conventional wastewater treatment process. However, DAF requires the circulation of water containing compressed air and requires expensive installation and operation cost. Plasma Air Flotation (PAF) process is able to float flocs by micro bubbles generated from underwater plasma without the circulation of bubbly water and additional saturators. Therefore, PAF can be an alternative solution overcoming economic barriers. In this study, Humic acid removal efficiency by PAF process was compared with that of sedimentation process. 44.67% and 87.3% reduction rate based on UV 254 absorbance has been measured in sedimentation and PAF respectively. In particular, PAF in the flocculation zone can dramatically remove humic acid from water. In flocculation zone, PAF can separate organic matters but sedimentation cannot.

전기부상공정에서 촉매성 산화물 전극에 따른 기포 발생량과 크기에 관한 연구 (Study on Bubble Generation and Size by Dimensionally Stable Anode in Electroflotation Process)

  • 김동석;박영식
    • 한국환경과학회지
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    • 제16권10호
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    • pp.1189-1195
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    • 2007
  • Small gas bubbles are used in many environmental and industrial processes for solid-liquid separations or to facilitate heat and mass transfer between phases. This study examines some of the factors that affect the bubble volume and size processed in the EF (electroflotation) process. The effect of electrode material, NaCl dosage, current and electrode distance were studied. The results showed that the generated bubble volume with electrode material lay in: Pt/Ti ${\fallingdotseq}$ Ru/Ti ${\fallingdotseq}$ Ir/Ti > Ti electrode. The more NaCl dosage was high, the smaller bubble was generated due to the low electric power. Bubble generation was increased with increase of current. With the increase of NaCl dosage, bubble generation was increased at same electric power (16.2 W). Generated bubble volume was not affected by electrode distance. However, no clear trends in bubble size as a function of these parameters were evident.

극한 환경 MEMS용 2" 3C-SiC기판의 직접접합 특성 (Direct Bonding Characteristics of 2" 3C-SiC Wafers for Harsh Environment MEMS Applications)

  • 정귀상
    • 한국전기전자재료학회논문지
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    • 제16권8호
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    • pp.700-704
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    • 2003
  • This paper describes on characteristics of 2" 3C-SiC wafer bonding using PECVD (plasma enhanced chemical vapor deposition) oxide and HF (hydrofluoride acid) for SiCOI (SiC-on-Insulator) structures and MEMS (micro-electro-mechanical system) applications. In this work, insulator layers were formed on a heteroepitaxial 3C-SiC film grown on a Si (001) wafer by thermal wet oxidation and PECVD process, successively. The pre-bonding of two polished PECVD oxide layers made the surface activation in HF and bonded under applied pressure. The bonding characteristics were evaluated by the effect of HF concentration used in the surface treatment on the roughness of the oxide and pre-bonding strength. Hydrophilic character of the oxidized 3C-SiC film surface was investigated by ATR-FTIR (attenuated total reflection Fourier transformed infrared spectroscopy). The root-mean-square suface roughness of the oxidized SiC layers was measured by AFM (atomic force microscope). The strength of the bond was measured by tensile strength meter. The bonded interface was also analyzed by IR camera and SEM (scanning electron microscope), and there are no bubbles or cavities in the bonding interface. The bonding strength initially increases with increasing HF concentration and reaches the maximum value at 2.0 % and then decreases. These results indicate that the 3C-SiC wafer direct bonding technique will offers significant advantages in the harsh MEMS applications.ions.

전해부상에 의한 상수 슬러지 농축효율 (Sludge Thickening using Electro-Flotation in Water Treatment Plant)

  • 이준;한무영;독고석;박용효;김충일;김미경
    • 상하수도학회지
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    • 제19권2호
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    • pp.155-160
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    • 2005
  • Gravity thickening process has been widely used in WTP sludge thickening at domestic water treatment plant. The operation method of the process is very simple, however, the process requires long detention time about 24~48 hours for sludge thickening, uses polymer, and low total solids of thickened sludge to increase sludge thickening efficiency. To solve there problems, we studied about flotation process, especially, electro-flotation (EF) process in WTP sludge thickening. Electro-flotation process is simpler than dissolved-air-flotation(DAF) process because EF needs only electrode and current to generate micro-bubbles and the operation is easy. This study was performed at two batch columns to compare interface height, total solids, effluent turbidity between an electro-flotation thickening and a gravity thickening. According to the result, an electro-flotation thickening was that interface height was decreasing, total solids had high concentration, and effluent turbidity was low in comparison with a gravity thickening. Also, it will make the high efficiency of following process, such as a dehydrating process and digestive process. because of high total solids and low moisture content in the sludge.

가스하이드레이트 산업시스템 실용화 현황 및 동향 분석 (Investigation on the Practical Use of Gas Hydrate in Gas Industry)

  • 권옥배;신창훈;박승수;한정민;이정환
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2006년도 춘계학술대회
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    • pp.415-418
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    • 2006
  • In Japan, research and development were undertaken on gas hydrate-side industrial processes associated with power generation system connections that may particularly be necessary to develop gas hydrated technology-based industrial systems. In so doing, data and engineering technologies useful n formulating guidelines on design of practical process were accumulated. In addition, basic research into theoretical evidence were carried out to promote and support the development of technological elements for those processes. In basic research designed to promote and support the research and development of elemental technologies microanalyses were conducted to understand the decomposition mechanism of mixed gas hydrate. Moreover, measurement technologies that can be applied in industrial processes, such as numerical analyses and concentration ion measurement, were examined. Japan has developed a highly efficient gas hydrate formation process using micro-bubbles with a tubular reactor. Higher formation rate over conventional systems has been obtained by the process. As mentioned above, the technical problems were clarified and the economics were studied from a view point of the NGH technology in this study. The results can be applied for utilization and must contribute to popularization of gas hydrate production.

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