• Title/Summary/Keyword: 막모듈

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Appropriate Technology and Field Application of Non-powered Water Purification System Using Nanofiber Membrane (나노섬유 멤브레인 기반 무동력 정수 시스템의 적정기술 및 현장 적용)

  • Lee, Jin;Yun, Byeong Gweon;Han, Kyoung Gu;Lee, Seung Hoon;Kim, Cheol Hyeon;Kim, Chan;Lee, Yunho;Lee, Dongwhi;Lee, Seunghyeok;Kim, Kyoung-Woong
    • Journal of Appropriate Technology
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    • v.7 no.1
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    • pp.72-81
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    • 2021
  • Gravity-driven membrane (GDM) filtration system based on the nanofiber membrane was investigated. This system can be operated with little energy demand due to a gravitational pressure-driven filtration and biological fouling control strategy. Moreover, the optimal module configuration based on the high permeance of nanofiber membrane can provide a significantly high water productivity. In order to evaluate its applicability potential, the pilot-scale (3000-5000 L/day) systems with nanofiber membranes were operated in developing countries (Kiribati and Tuvalu). Our results showed that the 14-92 L/(m2×h) of the permeate flux was determined indicating a stabilized water productivity. In addition, the permeate water indicated a high removal rate (more than 99.99%) of turbidity and bacteria. Consequently, the system can provide a stabilized water production with safe permeate water quality during long-term operation. These findings exemplify an effective approach to decentralized drinking water treatment for developing countries.

The Integration of heterogeneous applications through Plug-and Play (플러그 앤드 플래이(Plug-and-Play)개념을 이용한 이형 응용 프로그램의 통합 기법)

  • Baek, Sun-Cheol;Choe, Jung-Min;Jang, Myeong-Uk;Park, Sang-Gyu;Min, Byeong-Ik;Im, Yeong-Hwan
    • The Transactions of the Korea Information Processing Society
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    • v.2 no.6
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    • pp.947-959
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    • 1995
  • In this paper, we discuss an effort to develop a multi-agent architecture through which heterogeneous applications communicate and cooperate by means of plug-and play mechanism. Three componets are created in order to challenge the plug-and-play mechanism : meta-information, PnP agent module, and ICM. The meta- information is used to automatically set up a suitable configuration for a new plugged application, eliminating the need for direct addressing among heterogeneous applications. The PnPagent module is a homogeneous controller that operates on an application to ensure that its activities are coordin ated with those of the others within the community, provides a homogeneous communication envelope for all heterogeneous applications. The combination of these three components is used to meet the desire for implementing the plug-and-play mechanism. In this distributed, open architecture, one should be able to simply plug in a new application and it should work.

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Development of Adsorptive Permeation Membrane (APM) and Process for Separation of $CO_2$ from gas mixtures (이산화탄소 분리를 위한 흡착투과막 및 공정 개발)

  • Yeom, Choong Kyun;Ahn, Hyo Sung;Kang, Kyeong Rok;Kim, Joo Yul;Han, Jin-Soo;Kwon, Keun-Oh
    • Membrane Journal
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    • v.23 no.6
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    • pp.409-417
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    • 2013
  • Adsorptive permeation hollow fiber membrane (APM) has been developed for effectively separating $CO_2$ from gas mixture. Inside the APM, zeolite 13X particles were uniformly dispersed without covering their surfaces by a symmetric porous structure of polypropylene lattice. In this study, $CO_2/N_2$ mixture was used as a simulated gas mixture. Separation was achieved by adsorbing $CO_2$ on the zeolite particles in the APM and then permeating $N_2$ into permeate side in passing all the feed gas through the APM. Adsorptive permeation tests were carried out with a set of APM modules, and the adsorptive permeation performances of the modules were analyzed from the test results. After saturation of the adsorbent with $CO_2$, the APM was regenerated by desorption of $CO_2$ from it through vacuuming both inside of outside of the APM hollow fiber, and the regeneration process of the APM by vacuuming was discussed in terms of regeneration efficiency and energy consumption.

Experimental Study on Separation of Cephalosprotin C by Spiral-Wound Reverse Osmosis Module (나권형 역삼투 모듈에 의한 Cephalosporin C의 농축분리에 관한 실험연구)

  • Shin, Dong-Youp;Ryu, Jeung;Lee, Yong-Chul
    • Applied Chemistry for Engineering
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    • v.10 no.4
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    • pp.563-567
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    • 1999
  • Reverse osmosis concentration for cephalosproin C was studied using a polyamide composite membrane, FT-30 in spiral wound type with high solute rejection. The experiments were carried out in the aqueous solution of cephalosporin C for water flux, solute rejection and mass transfer coefficient under applied pressure of $4{\sim}20kg/cm^2$, feed concentration of 100~1000 mg/L and feed velocity of 2.8 and 5.6 L/min at room temperature. The effect of operating pressure on the separation of cephalosporin C showed that permeate flux increased with increasing operation pressure. These results are consistent with those predicted by Kedem-Katchalsky model. Solute rejection was nearly 1. The increase of feed concentration caused the reduction of cephalosporin C rejection, which was higher at low concentration than at high concentration, but degree of reduction was small.

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A Study on Ni Electroless Plating Process for Solder Bump COG Technology (COG용 Solder Bump 제작을 위한 Ni 무전해 도금 공정에 관한 연구)

  • Han, Jeong-In
    • Korean Journal of Materials Research
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    • v.5 no.7
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    • pp.794-801
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    • 1995
  • To connect the driver IC and Al coated glass, a method has been developed to plate electrolessly Ni on Al/PR system. It Is necessary to pretreat Al to remove oxide film before plating. In order to find pretreatment process which does not damage photoresist or glass, alkaline and fluoride zincate process have been investigated. Because photoresist and aluminum thin film can easily dissolve in alkaline solution, it is considered that the fluoride zincate process was a suitable one. After immersion in the zincate solution containing 1.5 g/$\ell$ ammonium bifluoride and 100 g/$\ell$ zinc sulfate, electroless nickel plating could be performed. The additive in the zincate solution and thiourea in the plating solution increased smoothness of the plated surface. Acld dip could improve the uniformit of the surface.

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Effect of Membrane Module and Feed Flow Configuration on Performance in Pressure Retarded Osmosis (압력지연삼투(PRO) 공정에서 막 모듈 배치와 유입원수의 유입 흐름방식이 성능에 미치는 영향)

  • Go, Gilhyun;Kim, Donghyun;Park, Taeshin;Kang, Limseok
    • Journal of Korean Society of Water and Wastewater
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    • v.30 no.3
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    • pp.271-278
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    • 2016
  • Recently, reverse osmosis (RO) is the most common process for seawater desalination. A common problem in both RO and thermal processes is the high energy requirements for seawater desalination. The one energy saving method when utilizing the osmotic power is utilizing pressure retarded osmosis (PRO) process. The PRO process can be used to operate hydro turbines for electrical power production or can be used directly to supplement the energy required for RO desalination system. This study was carried out to evaluate the performance of both single-stage PRO process and two-stage PRO process using RO concentrate for a draw solution and RO permeate for a feed solution. The major results, were found that increase of the draw and feed solution flowrate lead to increase of the production of power density and water permeate. Also, comparison between CDCF and CDDF configuration showed that the CDDF was better than CDCF for stable operation of PRO process. In addition, power density of two-stage PRO was lower than the one of single-stage. However, net power of two-stage PRO was higher than the one of single-stage PRO.

A method to maintain templates in open source-based authoring tool for e-learning assessment items (오픈 소스 기반의 이러닝 평가문항 저작 도구를 위한 템플릿 유지 기법)

  • Han, Sungjae;Choi, Byung-Uk;Cha, Jaehyuk
    • Journal of Digital Contents Society
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    • v.15 no.1
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    • pp.101-112
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    • 2014
  • Existing tools using in the standard e-learning contents authoring were used a method to provide users contents template produced in advance. In order to use resources of the template in a common web-based authoring tool, there is problem to overcome. If the resource of template is inserted within the contents on the authoring tool, the deformation of the template by the user's input that may occur during the edit process cannot be controlled. In this paper, we propose an effective maintenance method to prevent deformation of the resource of template inserted into any WYSIWYG-based HTML authoring tool by user's discretion. We added a template plug-in that can create the IMS-QTI standard resource in tynyMCE the web-based open source editor of representative examples. And the plug-in for tinyMCE was realized as a module of directly respond to the action of limited user input. So, in response to the action of user's input, the structure of the template can be sustained possibly.

Development of Ceramic Hollow Fiber Membrane Contactor Modules for Carbon Dioxide Separation (이산화탄소 분리용 세라믹 중공사 접촉막 모듈 기술 개발)

  • Lee, Hong Joo;Che, Jin Woong;Park, Jung Hoon
    • Journal of Climate Change Research
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    • v.7 no.3
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    • pp.249-256
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    • 2016
  • Porous $Al_2O_3$ hollow fiber membranes were successfully prepared by dry-wet spinning/sintering method. The SEM image shows that the $Al_2O_3$ hollow fiber membrane consists mostly of sponge pore structure. The contact angle and the breakthrough pressure were $126^{\circ}$ and 1.91 bar, respectively. This results indicate that the $Al_2O_3$ hollow fiber membranes were successfully modified to hydrophobic surface. The hydrophobic modified $Al_2O_3$ hollow fiber membranes were assembled into a membrane contactor system to separate $CO_2$ from a model gas mixture of the flue gas at elevated gas velocity. The $CO_2$ absorption flux was enhanced when the gas velocity increased from $1{\times}10^{-3}$ to $6{\times}10^{-3}$ m/s. Whereas the $CO_2$ absorption flux was decreased with the number of hollow fiber membrane of a module because of the concentration polarization. Furthermore, we developed an lab-scale $Al_2O_3$ hollow fiber membrane contactor modules and their system (i.e., $CO_2$ absorption using the $Al_2O_3$ membrane and monoethanolamine (MEA)) that could dispose of over $0.02Nm^3/h$ mixture gas (15% $CO_2$) with the removal efficiency higher than 95%. The results can be useful in a field of the membrane contactor for $CO_2$ separation, helping to design and extend a equipment.

Privacy Preserving User Authentication Using Biometric Hardware Security Module (바이오 보안토큰을 이용한 프라이버시 보호형 사용자 인증기법)

  • Shin, Yong-Nyuo;Chun, Myung-Geun
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.22 no.2
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    • pp.347-355
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    • 2012
  • A biometric hardware security module is a physical device that comes in the form of smartcard or some other USB type security token is composed with biometric sensor and microcontroller unit (MCU). These modules are designed to process key generation and electronic signature generation inside of the device (so that the security token can safely save and store confidential information, like the electronic signature generation key and the biometric sensing information). However, the existing model is not consistent that can be caused by the disclosure of an ID and password, which is used by the existing personal authentication technique based on the security token, and provide a high level of security and personal authentication techniques that can prevent any intentional misuse of a digital certificate. So, this paper presents a model that can provide high level of security by utilizing the biometric security token and Public Key Infrastructure efficiently, presenting a model for privacy preserving personal authentication that links the biometric security token and the digital certificate.

The Effect of Extrusion Temperature on Microstructure and Thermoelectric Properties of Rapidly Solidified P-type $P-type Bi_{0.5}Sb_{1.5}Te_3$ alloy (급속응고된 $P-type Bi_{0.5}Sb_{1.5}Te_3$ 합금 열전재료의 미세조직과 열전특성에 미치는 압출 온도의 효과)

  • 이영우;천병선;홍순직;손현택
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2001.11a
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    • pp.28-28
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    • 2001
  • $Bi_2Te_3$계 열전반도체 재료는 200 ~ 400K 정도의 저온에서 에너지 변환 효율이 가장 높은 재료로서 열전냉각 및 발전재료로 제조볍 및 특성에 관한 많은 연구가 진행되어 왔다. 전자냉각 모듈의 제조에는 P형 및 N형 $Bi_2Te_3$계 단결정이 주로 사용되고 있으나. $Bi_2Te_3$ 단결정은 C축에 수직한 벽개면을 따라 균열이 쉽게 전파하기 때문에 소자 가공사 수윤 저하가 가장 큰 문제점으로 지적되고 있다. 이에 따라 최근 열전재료의 가공방법에 따른 회수율 증가 및 열전특성 향상에 관한 열간압출, 단조와 같은 연구가 활발히 이루어지고 있다. 본 연구는 가스분사법(gas atomizer)을 이용하여 용질원자 편석의 감소, 고용도의 증가,균일고용체 형성, 결정립미세화 둥 급속응고의 장점을 이용하여 화학적으로 균질한$Bi_2Te_3$계 열전재료 분말을 제조하고, 제조된 분발을 압출가공하여 기계적성질, 소자의 가공성 및 열전 성능 지수율 향상시키는데 연구 목적이 있다. 본 설험에서는 99.9%이상의 고순도 Bi. Te. Se. Sb를 이용하여, 고주파 유도로에서 Ar 분위기로 용융하고, 가스분사법를 이용하여 균질한 $Bi_2Te_3$계 열전재료 분만을 제조하였다. 분말표면의 산화막을 제거하기 위하여 수소분위기에서 환원처리를 행하였고, 된 분말을 Al 캔 주입하여 냉간성형 한 후 진공중에서 압출온도를 변화시켜 열간압출 가공을 행하였다. 압출 온도변화에 따른 압출재의 미세조직 및 열전특성에 중요한 영향을 미치는 C면 배향에 대한 결정방위 해석, 압출재의 압축강도 등을 분석하였으며, 압출온도에 따삼 미세조직 변화와 결정방위의 변화에 따른 열전특성의 관계를 해석하였다성시켰고 이들이 산인 HNO3에서 녹았기 때문이다. 본 연구에서 개발된 새로운 에칭 용액인 90H2O2 - 10HNO3 (vol%)의 에칭 원리가 똑같이 적용 가능한 다른 종류의 초경 합금에서도 사용이 가능할 것으로 판단된다.로 판단된다.멸과정은 다음과 같다. 출발물질인 123 분말이 211과 액상으로 분해될 때 산소가스가 배출되며, 이로 인해 액상에서 구형의 기공이 생성된다. 이들 중 일부는 액상으로 채워져 소멸되나, 나머지는 그대로 남는다. 특히, 시편 중앙에 서는 수십-수백 마이크론 크기의 커다란 기공이 다수 관찰된는데, 이는 기공의 합체로 만들어진 것이다. 포정반응 열처리 시 기공 소멸로 만들어진 액상포켓들은 주변 211 입자와 반응하여 123 영역으로 변한다. 이곳은 다른 지역과 비교하여 211 밀도 가 낮기 때문에, 미반응 액상이 남거나 211 밀도가 낮은 123 영역이 된다. 액상으로 채워지지 못한 구형의 기공들 중 다수가 123 결정 내로 포획되며, 그 형상은 액상/ 기공/고상 계면에너지에 의해 결정된다.단의 경우, 파단면이 매끄럽고 파변상의 결정립도 매우 미세하였으며, 산확물 의 용집도 찾아보기 어려웠 나, 접합부 파단의 경우에는 파변의 굴곡이 비교척 심하고 연성 입계파괴의 형태를 보였£며, 결정립도 모채부 파단의 경우에 비해 조대하였다. 조대하였다. 셋째, 주상기간 중 총 에너지 유입률 지수와 $Dst_{min}$ 사이에 높은 상관관계가 확인되었다. 특히 환전류를 구성하는 주요 입자의 에너지 영역(75~l13keV)에서 가장 높은(0.80) 상관계수를 기록했다. 넷째, 회복기 중에 일어나는 입자들의 유입은 자기폭풍의 지속시간을 연장시키는 경향을 보이며 큰 자기폭풍일수록 현저했다. 주상에서 관측된 이러한 특성은 서브스톰 확장기 활동이 자기폭풍의

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