• Title/Summary/Keyword: Surface Mat

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Application of Atomic Layer Deposition to Electrodes in Solid Oxide Fuel Cells

  • Kim, Eui-Hyeon;Hwang, Heui-Soo;Ko, Myeong-Hee;Bae, Seung-Muk;Hwang, Jin-Ha
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.08a
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    • pp.319.1-319.1
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    • 2013
  • Solid oxide fuel cells (SOFCs) have been recognized as one of emerging renewable energy sources, due to minimized pollutant production and high efficiency in operation. The performance of SOFCs is largely dependent on the electrode polarization which involves the oxidation/reduction in cathodes and anodes along with the charge transport of ions and electronic carriers. Atomic layer deposition is based on the alternate chemical surface reaction occurring at low temperatures with high uniformity and superior step coverage. Such features can be extended into the coating of metal oxide and/or metal layer onto the porous materials. In particular, the atomic layer deposition is can manipulated in controlling the charge transport in terms of triple phase boundaries, in order to control artificially the electrochemical polarization in electrodes of SOFC. The current work applied atomic layer deposition of metal oxides intro the electrodes of SOFCs. The corresponding effect was monitored in terms of the electrochemical characterization. The roles of atomic layer deposition in solid oxide fuel cells are discussed towards optimized towards long-term durability at intermediate temperature.

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Formation of Silver Nanoparticles on Silica by Solid-State Dewetting of Deposited Film (증착 박막의 비젖음에 의한 실리카 표면 위 은나노 입자형성)

  • Kim, Jung-Hwan;Choi, Chul-Min;Hwang, So-Ri;Kim, Jae-Ho;Oh, Yong-Jun
    • Korean Journal of Metals and Materials
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    • v.48 no.9
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    • pp.856-860
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    • 2010
  • Silver nanoparticles were formed on silica substrates through thin film dewetting at high temperature. The microstructural and morphological evolution of the particles were characterized as a function of processing variables such as initial film thickness, annealing time, and temperature. Silver thin films were deposited onto the silica using a pulsed laser deposition system and annealed in reducing atmosphere to induce agglomeration of the films. The film thicknesses before dewetting were in the range of 5 to 25 nm. A noticeable agglomeration occurs with annealing at temperatures higher than $300^{\circ}C$, and higher annealing temperature increases particle size uniformity for the same film thickness sample. Average particle size linearly correlates to the film thickness, but it does not strongly depend on annealing temperature and time, although threshold temperature for complete dewetting increases with an increase of film thickness. Lower annealing temperature develops faceted surface morphology of the silver particles by enhancing the growth of the low index crystal plane of the particles.

The Microstructures and Properties of Duplex Layer on the Tool Steel Formed by Post-oxidation and Sulfnitriding (금형공구강의 후산화와 침류질화에 의해 형성된 복합층의 조직과 특성에 관한 연구)

  • Lee, J.S.;Klm, H.G.;You, Y.Z.
    • Journal of the Korean Society for Heat Treatment
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    • v.14 no.2
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    • pp.81-88
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    • 2001
  • The effects of post-oxidation and sulfnitriding treatments on the phase transformation in the nitrided case of tool steels have been studied. Dense and compact $Fe_3O_4$ layer was formed at the outer surface of nitride compound layer by post-oxidation treatment and multi layer of iron sulfide(FeS) was formed in the compound layer by sulfnitriding treatment. The surface hardness decreased because of formation of the soft oxide or sulfide at the nitride surface. Diffusion layer of nitride case was not affected by post-oxidation treatment or sulfnitriding treatment of nitrided alloy tool steels.

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Dimension Reduction of Solid Models by Mid-Surface Generation

  • Sheen, Dong-Pyoung;Son, Tae-Geun;Ryu, Cheol-Ho;Lee, Sang-Hun;Lee, Kun-Woo
    • International Journal of CAD/CAM
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    • v.7 no.1
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    • pp.71-80
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    • 2007
  • Recently, feature-based solid modeling systems have been widely used in product design. However, for engineering analysis of a product model, an ed CAD model composed of mid-surfaces is desirable for conditions in which the ed model does not affect analysis result seriously. To meet this requirement, a variety of solid ion methods such as MAT (medial axis transformation) have been proposed to provide an ed CAE model from a solid design model. The algorithm of the MAT approach can be applied to any complicated solid model. However, additional work to trim and extend some parts of the result is required to obtain a practically useful CAE model because the inscribed sphere used in the MAT method generates insufficient surfaces with branches. On the other hand, the mid-surface ion approach supports a practical method for generating a two-dimensional ed model, even though it has difficulties in creating a mid-surface from some complicated parts. In this paper, we propose a dimension reduction approach on solid models based on the midsurface abstraction approach. This approach simplifies the solid model by abbreviating or removing trivial features first such as the fillet, mounting, or protrusion. The geometry of each face is replaced with mid-patches from the simplified model, and then unnecessary topological entities are deleted to generate a clean ed model. Also, additional work, such as extending and stitching mid-patches, completes the generation of a mid-surface model from the patches.

Application Cases of Test Construction of Hydro-Seeding Measures on the Slopes Along the National Road Between Gamchon and Yaechon (감천예천구간 국도비탈면 종자뿜어붙이기 시험시공 적용사례)

  • Jeon, Gi-Seong;Woo, Kyung-Jin
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.10 no.6
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    • pp.139-151
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    • 2007
  • To protect the surface of ground-cutting slopes and ground-raised slopes and to recover environment-friendly slopes at the national road expansion construction between Gamchon and Yaechon, test-construction work was done using several modes of hydro-seeding measures to select a suitable construction method through the field survey; the results were as follows : As a result of survey on physio-chemical characteristics of soil, the average soil inclination on ground-raised slopes was from 4.73 mm to 5.37 mm; the average soil acidity was from pH 6.47 to 6.73; the average soil humidity was within the scope of 0.57~1.70 %,; the average soil inclination on ground-cutting slopes was 9.17~10.43mm; the average soil acidity was pH 6.67~6.77 and the average soil humidity was within the scope of 0.53~1.27 %; considered overall, they showed generally satisfactory base materials for plant breeding. As a result of the number of sprouting individuals, the average sprouting number of individuals on test spots executed by Coir net with Seed spray construction methods and the average number of sprouting individuals on other test spots executed by furrow-digging with Seed spray and Straw mat-mulching measures were 1,172 number of per square meter and 970 number of per square meter respectively; thus they showed higher numerical value comparing with other test spots. Likewise, the average number of sprouting individuals on test spots of the ground-cutting slopes executed by Coir net with Seed spray method and the average number of sprouting individuals on other test spot executed by furrow-digger with Seed spray and Straw mat-mulching measures were found to be 1,107 number of per square meter and 1,105 number of per square meter respectively, whose numerical value showed rather higher other test spots. As a result of a survey on living plants' breeding index [dried weight], the weight in dried state on test spots executed by Coir net with Seed spray method and other test spots executed by furrow-digger with Seed spray and Straw mat-mulching measures on both ground-raised and ground-cutting slopes was found to be higher and showed similar characteristics statistically. As a result of survey on the surface-covering degree of ground-raised slopes, nine weeks after test construction, test spots executed by Coir net with Seed spray method and other test spots executed by furrow-digger with Seed spray and Straw mat-mulching measures showed commonly more than 70% of surface-covering degree, but other test spots showed only below 35% of surface covering degree; especially in case of test spots by Verdvol seed spray measures, they showed 10% of the lowest surface-covering. Surface-covering degree on the test spot of ground-cutting slopes nine weeks after test construction showed more than 75% both executed by Coir net with Seed spray construction method and executed by furrow-digger with Seed spray and Straw mat-mulching measures. As a result of survey on appearing plants on the test spots, there dominates Eragrostis curvula both on ground-raised slopes and on ground-cutting slopes with other seeding plant life's lower breeding and there appear intruders, such as Setaria viridis Beauv, Digitaria sanguinalis Scop, and Chenopodium album var.centrorubrum Makino. As for water-borne excavation and soil's washing-away on the slopes, there happened less washing-away and water-borne excavation with good breeding of plant life on test spots executed both by Coir net with Seed spray construction method and by furrow-digger with Seed spray and Straw mat-mulching measures, but there happened much more soil's washing-away along with water-home excavation at the test spot executed by Seed spray with measures. After the research results of test construction sites are examined overall, it's presumed that furrow-digger with Seed spray and Straw mat-mulching measures [interval between lines is 40cm, 5cm in depth] will be preferred to prevent erosion and water-home excavation of slopes located within the construction sites.

Steam Reforming of Biogas on Nickel Fiber Mat Catalysts (니켈 섬유 매트 촉매를 사용한 바이오가스 수증기개질 반응)

  • Bui, Quynh Thi Phuong;Kim, Yong-Min;Yoon, Chang-Won;Nam, Suk-Woo
    • Journal of Energy Engineering
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    • v.20 no.3
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    • pp.252-258
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    • 2011
  • Nickel fiber mat was investigated as a potential structured catalyst for steam reforming of biogas in the temperature range of $600-700^{\circ}C$. The activity of as-received catalyst was very low owing to the smooth surface of fibers. Pretreatment of the catalyst by oxidation followed by reduction under methane partial oxidation condition significantly improved the catalytic activity, although degradation of the activity was found during the reaction due to oxidation and sintering. This deactivation was retarded by supplying additional hydrogen in the inlet gases or by coating $CeO_2$ over the catalyst surfaces.

A Study on the Selection Method of Foundation Type in the Underground Parking Lot of Apartments (공동주택 지하 주차장 기초형식 선정방법에 관한 연구)

  • Im, Nam-Gi;Lee, Yeong-Do;Bae, Yong-Hwan
    • Journal of the Korea Institute of Building Construction
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    • v.4 no.3
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    • pp.109-116
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    • 2004
  • Normally easy task of plat in urban architecture is that using underground full of activities for increase building site efficiency. Especially for using underground space for the parking lot. Also utilize underground is more increase for fulfill requirement in modern society considered with environmental friendly architecture. The primary objective of this study is to apply analyzed formal foundation type for selecting the optimum type of parking lots considered with structural stability, economical efficiency, construction efficiency, construction duration. This study aim to on criteria decided through the questionaries for the selection considered with in the scale of second stories parking lots underground, parking volume is 80 and reinforced concrete structure. The bearing capacity is 6~8m and downward from surface, healthy ground bearing capacity is 40 t/m2. This study comparative analysis and discuss economical efficiency, construction efficiency, construction duration based constructivist stability which applied Single foundation, Mat foundation, Drop Mat foundation. The result of this study is as follows: First, the result of economical efficiency is that on the basis of single foundation, Drop Mat foundation is 1.88, Mat foundation 2.04 as a comparative analysis on the basis of total construction cost included material cost, labor coast and machinery cost. Second, the result of construction efficiency order is single foundation, Drop Mat foundation, Mat foundation as a comparative analysis on the based connected characteristics. Third, the result of construction duration is that on the basis of Mat Foundation, Drop Mat foundation is 1.33, single foundation is 1.87 as a comparative analysis Critical Path. Forth, Each foundational type characteristics order through the matrix method is that overall each formal type of foundation contraries at economical efficiency and construction efficiency, construction duration. Also expect contradiction between engineers and owners due to engineer pursuit construction duration and ewer to begin with economical efficiency. Fifth, The selection of suitable foundation formal type needs that based consider project characteristic and field condition as according to above result of a comparative analysis. As a result, a comparative analysis economical efficiency, construction efficiency, construction duration of Mat foundation, Drop Mat foundation, single foundation with 3Bay reinforced structure underground parking lots on the healthy ground.

Infrared Radiative Heat Transfer Characteristics of Fiber Mat Catalytic Burners (매트촉매 버너의 적외선 복사열전달 특성)

  • Song, Kwang Sup;Choi, Jung In
    • Korean Chemical Engineering Research
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    • v.50 no.6
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    • pp.1049-1055
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    • 2012
  • The fiber mat catalytic burner that uses infrared radiative heat obtained by flameless catalytic combustion was manufactured and tested to investigate its combustion characteristics. About 9 to 17% of combustion heat was released by sensible heat during the premixed catalytic combustion depend on combustion condition. To find out radiation intensity with distance between catalytic burner and sample, the equation that calculate the receiving surface of radiative energy under the fiber mat catalytic burner was driven. This equation was well correlated with the drying rate of melamine. The drying experiments were carried out to the melamine, wood chip and agricultural pallet by using the fiber mat catalytic burner and the energy efficiency was calculated from drying rate of them. The energy efficiency of the fiber mat catalytic burner reaches to 79% in maximum for drying of the wood chip.

Removal of Algae in a Slow Sand Filter using Ecological Property of Macrobenthos (Pomacea canaliculata) (저서생물의 환경생태학적 특성을 이용한 완속 모래여과지의 조류제거)

  • Son, Hee-Jong
    • Journal of Environmental Science International
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    • v.22 no.3
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    • pp.371-378
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    • 2013
  • After identifying species by collecting the suspended and attached algae mat inhabiting in the slow sand-filter, Spirogyra sp., Mougeotia sp. and Closterium sp. were main green algae and Synedra sp. was diatom algae. Among them green algae Spirogyra sp. was dominant species. A result of observing the life mode of apple snail for a month after introducing into the slow sand-filter, apple snail eggs were discovered on the filter walls 2 weeks after introducing, 4 weeks later lots of eggs were observed all of the slow sand-filter walls, it means there is no problem for apple snail to live in the slow sand-filter. The observation result for algae removal potential by introduced apple snail after 2 months later, slow sand-filter where apple snail were introduced, a few algal mat were observed. On the other hand, no introduced apple snail into the slow sand-filter, lots of suspended algal mats were formed in the water and attached algal mats on the sand surface as well, these algal mat induced much of operating problems.