• Title/Summary/Keyword: serpentine

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A Study on the meaning of in-between space in Sou Fujimoto and Bernard Tschumi's Architecture (소우 후지모토 건축과 베르나르 추미의 건축에 나타난 사이공간(In-between space) 개념에 대한 비교연구)

  • Park, Hohyun
    • Korean Institute of Interior Design Journal
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    • v.24 no.6
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    • pp.87-95
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    • 2015
  • Aldo Van Eyck and Herman Hertzberger explained 'In-between space' as an intermediate space between opposite elements such as whole and parts, inside and outside, open and close, central and decentral. From this idea, the meaning of 'in-between space' has developed and applied to works of Bernard Tschumi and Sou Fujimoto. In this study, the meaning of 'in-between space' was compared and analyzed based on two architects' works to reveal the design approach in terms of 'in-between space' Final Wooden House, N House, and Serpentine Gallery Pavilion among Sou Fujimoto's work were selected and Le Fresnoy, Lerner Student Center, and Acropolis Museum among Bernard Tschumi's work were selected to analyze. To understand their design approach, their works were compared and analyzed in architectural attitude, tools, construction style and the approach, concept, theme, relation, direction of in-between space. As a result, Sou Fujimoto uses 'in-between space' as a nebulous approach as intermediate space between opposite elements. For Bernard Tschumi, 'in-between space' is also an intermediate space to emphasize and make a tension between opposite elements. It is a method of solving the contradiction condition between old city environment and new architecture.

Development of high-performance heavy density concrete using different aggregates for gamma-ray shielding

  • Ouda, Ahmed S.
    • Advances in materials Research
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    • v.3 no.2
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    • pp.61-75
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    • 2014
  • This study aimed to investigate the suitability of some concrete components for producing "high-performance heavy density concrete" using different types of aggregates that could enhances the shielding efficiency against ${\gamma}$-rays. 15 mixes were prepared using barite, magnetite, goethite and serpentine aggregates along with 10% silica fume, 20% fly ash and 30% blast furnace slag to total OPC content for each mix. The mixes were subjected to compressive strength at 7, 28 and 90 days. In some mixes, compressive strengths were also tested up to 90 days upon replacing sand with the fine portions of magnetite, barite and goethite. The mixes containing magnetite along with 10% SF reaches the highest compressive strength exceeding over M60 requirement by 14% after 28 days. Whereas, the compressive strength of concrete containing barite was very close to M60 and exceeds upon continuing for 90 days. Also, the compressive strength of high-performance concrete incorporating magnetite fine aggregate was significantly higher than that containing sand by 23%. On the other hand, concrete made with magnetite fine aggregate had higher physico-mechanical properties than that containing barite and goethite. High-performance concrete incorporating magnetite fine aggregate enhances the shielding efficiency against ${\gamma}$-rays.

A Sensorless and Versatile Temperature-Control System for MEMS Microheaters (온도센서를 사용하지 않는 MEMS 마이크로히터 온도제어시스템)

  • Bae, Byung-Hoon;Yeon, Jung-Hoon;Flachsbart Bruce R.;Shannon Mark A.
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.55 no.11
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    • pp.544-547
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    • 2006
  • In this paper, we present a temperature-controlled system for MEMS electrical resistance heaters without a temperature sensor. To rapidly control the heater temperature, the microheater system developed consists of a power supply, power amplifier, digital ${\underline{P}}roportional-{\underline{I}}ntegral-{\underline{D}}ifferential$ (PID) controller, and a quarter bridge circuit with the microheater and three resistors are nominally balanced. The microheaters are calibrated inside a convection oven to obtain the temperature coefficient with a linear or quadratic fit. A voltage amplifier applies the supply voltage proportional to the control signal from the PID controller. Small changes in heater resistance generate a finite voltage across the quarter bridge circuit, which is fed back to the PID controller to compare with the set-point and to generate the control signal. Two MEMS microheaters are used for evaluating the developed control system - a NiCr serpentine microheater for a preconcentrator and a Nickel microheater for ${\underline{P}}olymerase\;{\underline{C}}hain\;{\underline{R}}eaction$ (PCR) chip.

Window Integrated Solar Collectors (창호일체형 태양열 집열기)

  • Park, Seong-Bae;Lim, Seong-Whan;Park, Mann-Kwi
    • 한국태양에너지학회:학술대회논문집
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    • 2009.04a
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    • pp.61-65
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    • 2009
  • Window integrated solar collector is to simply install inside of the existing double glass window frame. Double glass window frame is consist of inner glass of Low-E coating and Silver coating, and outer glass of low iron reinforced glass. In order to secure natural lighting in a room, only 50% of window frame is covered with solar collectors. Solar absorption or transmission rate varies seasonally depending on sun angles. Part of inner glass where right behind of the solar plate is covered with silver coating to increase absorption rate of solar plate. The collector is made of a copper serpentine where aluminum fins are soldering. To improve the effect of insulation of inside of the window frame is recommend vacuum. As a result, we are making the 3th sample and will archieve below $F_RU_L=7.5W/m^2^{\circ}C$ that is the account of heat lossed, and above $F_R({\tau}{\alpha})=0.45$.

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Technology of Flexible Semiconductor/Memory Device (유연 반도체/메모리 소자 기술)

  • Ahn, Jong-Hyun;Lee, Hyouk;Choa, Sung-Hoon
    • Journal of the Microelectronics and Packaging Society
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    • v.20 no.2
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    • pp.1-9
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    • 2013
  • Recently flexible electronic devices have attracted a great deal of attention because of new application possibilities including flexible display, flexible memory, flexible solar cell and flexible sensor. In particular, development of flexible memory is essential to complete the flexible integrated systems such as flexible smart phone and wearable computer. Research of flexible memory has primarily focused on organic-based materials. However, organic flexible memory has still several disadvantages, including lower electrical performance and long-term reliability. Therefore, emerging research in flexible electronics seeks to develop flexible and stretchable technologies that offer the high performance of conventional wafer-based devices as well as superior flexibility. Development of flexible memory with inorganic silicon materials is based on the design principle that any material, in sufficiently thin form, is flexible and bendable since the bending strain is directly proportional to thickness. This article reviews progress in recent technologies for flexible memory and flexible electronics with inorganic silicon materials, including transfer printing technology, wavy or serpentine interconnection structure for reducing strain, and wafer thinning technology.

Thermal and Flow Analysis in a Proton Exchange Membrane Fuel Cell

  • Jung, Hye-Mi;Koo, Ja-Ye
    • Journal of Mechanical Science and Technology
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    • v.17 no.9
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    • pp.1358-1370
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    • 2003
  • The effects of anode, cathode, and cooling channels for a Proton Exchange Membrane Fuel Cell (PEMFC) on flow fields have been investigated numerically. Continuous open-faced fluid flow channels formed in the surface of the bipolar plates traverse the central area of the plate surface in a plurality of passes such as a serpentine manner. The pressure distributions and velocity profiles of the hydrogen, air and water channels on bipolar plates of the PEMFC are analyzed using a two-dimensional simulation. The conservation equations of mass, momentum, and energy in the three-dimensional flow solver are modified to include electro-chemical characteristics of the fuel cell. In our three-dimensional numerical simulations, the operation of electro-chemical in Membrane Electrolyte Assembly (MEA) is assumed to be steady-state, involving multi-species. Supplied gases are consumed by chemical reaction. The distributions of oxygen and hydrogen concentration with constant humidity are calculated. The concentration of hydrogen is the highest at the center region of the active area, while the concentration of oxygen is the highest at the inlet region. The flow and thermal profiles are evaluated to determine the flow patterns of gas supplied and cooling plates for an optimal fuel cell stack design.

An Experimental Study on Cooling of Hydration Heat of Mass Concrete Structure using Pulsating Heat Pipe in Summer Season (진동형 히트 파이프를 이용한 하계 매스 콘크리트의 수화열 냉각에 관한 실험적 고찰)

  • Yang, Tae-Jin;Kim, Jeong-Hoon;Kim, Jong-Soo
    • Journal of Advanced Marine Engineering and Technology
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    • v.31 no.1
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    • pp.51-57
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    • 2007
  • In process of reinforced concrete (RC) box structure. the heat of hydration may cause serious thermal cracking. In order to eliminate hydration heat of mass concrete. this paper reports results of hydration heat control in mass concrete structure using the pulsating heat pipe. There were three RC box molds($1.2{\times}l.8{\times}2.4m^3$) which shows a difference as compared with each other. One was not equipped with pulsating heat pipe. The others were equipped with pulsating heat pipe. All of them were cooled with natural air convection. The pulsating heat pipe was composed of serpentine type copper pipe with 10 turns (outer diameter: 4mm. inner diameter: 2.8mm). The working fluid was R-22 and its charging ratio was 40% by volume. The conditions such as the number of turns. the length and the pitch of the pulsating heat pipe and the size of concrete structure were changed. Based on these experiments, it was confirmed that this construction method using pulsating heat pipe was effective to remove hydration heat of mass concrete structure and thus it was possible to prevent harmful thermal crack and construction Period and costs of concrete structure would be cut down.

Comparison of the Heavy Metal Concentrations of the Soils and Plants at the Serpentine and Rhyolite Resions in Ulsan City (울산시의 사문암 및 유문암 지역 표토와 식물체의 중금속 함량 비교)

  • 김명희;민일식;송석환
    • Korean Journal of Environment and Ecology
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    • v.13 no.2
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    • pp.176-183
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    • 1999
  • 울산지역의 사문암과 유문암 토양 및 쑥과 참억새의 중금속 함량을 비교하기 위하여 중금속 농도를 분석한 결과 사문암 풍화토의 Ni, Cr 및 Co 함량은 매우 높았다. Ni은 1,483~1.524ppm, Cr은 372~435ppm, Co는 68~79ppm였으며, 유문암 풍화토의 Zn 함량은 222ppm으로 사문암 풍화토보다 높았다. 사문암 풍화토에서 생육하는 쑥의 중금속 함량은 Ni이 108~195ppm. Cr이 135~180ppm, Co가 10.2~22.5ppm으로 유문암 풍화토의 쑥보다 높았고, Zn은 유문암 토양 쑥에서 높았다. 참억새의 경우는 Ni, Cr, Co, As, Se, Mo 및 Fe 가 사문암 토양에서 높았고, Zn 흡수는 유문암 토양에서 많았다. 쑥의 중금속 함량은 대체적으로 지상부가 지하부보다 높았으나, 참억새의 경우는 지하부가 높은 경향을 나타내었다. 토양과 식물체(쑥과 참억새)의 중금속 함량을 비교해 보면 Ni, Cr, Co, As, Sc, Mo 및 Fe의 함량은 토양의 식물체보다 높았으나, 유문암 토양에 있는 쑥의 Zn 흡수는 토양보다 다소 높았다. 식물체의 Fe:Ni 비율은 유문암 토양보다는 사문암 토양이, 참억새보다는 쑥이 낮게 나타났다.

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Genesis of Talc Ore Deposits in the Yesan Area of Chungnam, Korea (충남(忠南) 예산지구(禮山地區) 활석광상(滑石鑛床)의 성인(成因)에 관(關)한 연구(硏究))

  • Woo, Young-Kyun;Choi, Suck-Won;Park, Ki-Hwa
    • Economic and Environmental Geology
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    • v.24 no.4
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    • pp.363-378
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    • 1991
  • Field and microscopic evidence, XRD,EPMA and chemical data suggest that parent rock of talc ore deposits of Yesan district was originated from ultramafic igneous rock. Parent rock can be divided into serpentinized dunite, serpentinized peridotite, metagabbro, amphibolite and hornblende schist. The ore deposits are highly sheared, and show many evidences of hydrothermal alteration and metamorphism at the greenschist and albite-epidote amphibolite facies. The process of steatitization is variable depending upon the composition, and the degree of alteration and metamorphism of the parent rocks. Steatitization can be divided into two processes with or without serpentinization. The parent rocks with serpentinization are serpentinized dunite, serpentinized peridotite and metagabbro, showing the following alteration process; olivine ${\rightarrow}$ serpentine${\rightarrow}$ talc. The rocks without serpentinization are amphibolite and hornblende schist showing the following sequence; hornblende${\rightarrow}$ chlorite${\rightarrow}$ talc. Formation of talc deposits is summarized as following six stages; I) Intrusion of ultramafic rocks, 2) autometamorphism, 3) metamorphism at greenschist and albite-epidote-amphibolite facies, 4) brittle deformation, 5) hydrothermal alteration, 6) purification of low-grade talc by late dyke intrusion.

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Real-Time Detection of Residual Free Chlorine and pH in Water Using a Microchannel Device

  • Kim, Sam-Hwan;Choi, Ju-Chan;Lee, June-Kyoo;Kong, Seong-Ho
    • Journal of Sensor Science and Technology
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    • v.20 no.6
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    • pp.368-374
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    • 2011
  • A microfluidic device for real-time monitoring of residual free chlorine and pH in water based on optical absorption is proposed. The device consists of a serpentine micromixer for mixing samples with a reagent, and a photodiode and light emitting diode(LED) for the detection of light absorbance at specific wavelengths, determined for specific reagent combinations. Spectral analyses of the samples mixed with N, N'-diethyl-p-phenylenediamine(DPD) reagent for chlorine determination and bromothymol blue(BTB) for pH measurement are performed, and the wavelengths providing the most useful linear changes in absorbance with chlorine concentration and pH are determined and used to select the combination of LED and photodiode wavelengths for each analyte. In tests using standard solutions, the device is shown to give highly reproducible results, demonstrating the feasibility of the device for the inexpensive and continuous monitoring of water quality parameters with very low reagent consumption.