• Title/Summary/Keyword: 인공구조물의 영향

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A Study on Elongation/Contraction Behavior and Mechanical Properties of Oxy-Polyacrylonitrile(PAN) Fiber in Basic/Acidic Solution for Artificial Muscle Applications (산화된 폴리아크릴로니트릴 섬유의 인공근육 응용을 위한 염기/산 용액에서의 신장/수축 거동과 기계적 특성 연구)

  • 이영관;김상완;이경섭;조인희;이주화
    • Polymer(Korea)
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    • v.26 no.4
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    • pp.468-476
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    • 2002
  • Oxy-PAN fiber prepared from the preoxidation and saponification of raw PAN fiber is known to elongate and contract when immersed in basic and acidic solutions, respectively. In this study, about 30% elongation in NaOH solution and 30∼50% contraction in HCl solution have been observed. In mechanical test, the mechanical properties of oxy-PAN fiber in the contracted state was stronger than that in the elongated state. These behaviors and mechanical properties are compared to those of living muscle and linear actuator. The change of length in NaOH and HCl solutions is due to switching between a hydrophilic and a hydrophobic structure. Other reasons are exchange of ion and water in/out of oxy-PAN fiber, and osmotic pressure difference associated with relevant ions. Much studies are needed to clarify the effective factors on but the oxy-PAN fiber's elongation/contraction behavior and mechanical properties, but the oxy-PAN fiber perpared in our laboratory has a sufficient potential for application as artificial muscle and linear actuator.

Recovery of Fish Community and Water Quality in Streams Where Fish Kills have Occurred (어류폐사의 발생 이후 하천에서 수질의 변화 및 어류상 회복)

  • Lee, Jae-Yong;Lee, Kwang-Yeol;Lee, Saeromi;Choi, Jaeseok;Lee, Seok-Jong;Jung, Sungmin;Jung, Myoung-Sook;Kim, Bomchul
    • Korean Journal of Ecology and Environment
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    • v.46 no.2
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    • pp.154-165
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    • 2013
  • The species composition of the fish community was studied in four streams where fish kills have previously occurred in recent years; Worun Stream, Seo Stream, Jangnam Stream, and the Anyang Stream. The number of fish species varied from 22 to 86% compared to the number of fish species pre-fish kill. The recovery of fish populations in the streams seems to be determined by water quality and the presence of artificial structures in the streams. The Jangnam Stream, where alkaline pH caused a fish kill, showed a high recovery of fish species due to improvements in water quality. Anyang Stream had a low number of species, possibly because dissolved oxygen concentrations were intermittently low. Artificial structures in streams had a negative impact the recovery of fish species, particularly for benthic fish species. It appears that fish populations can recover rapidly when water quality improves or the movement of fish community is unimpeded. However, water quality and artificial structures in many streams in Korea still present adverse conditions for fish survival, deterring the recovery of fish populations. To conserve fish populations in streams, habitat all owing unimpeded movement for fish and controls on pollutant inputs are needed.

Development and application of soil moisture prediction using real-time in-situ observation and machine learning (실시간 현장관측과 기계학습을 이용한 토양수분 예측기술의 개발 및 적용)

  • Hyuna Woo;Yaewon Lee;Minyoung Kim;Seong Jin Noh
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.286-286
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    • 2023
  • 물의 전체 순환 구조에서 토양수분이 차지하는 정량적 비중은 상대적으로 작지만, 강우-유출 과정의 비선형에 영향을 미치는 지배적 요인 중 하나이고, 토양 침식과 산사태, 농업생산량, 기후 변화 대응 등 광범위한 주제와 연관되어 있어, 토양수분의 물리과정에 대한 이해 증진과 예측 기술의 지속적인 개선이 필요하다. 본 연구에서는 금오공과대학교 유역 내에서 토양수분과 기상 요소를 실시간 관측하고, 기계학습 기법을 이용하여 토양수분을 단기 예측하는 기술을 개발하고 평가한다. 구체적으로는, 토양 관측 장비인 TEROS를 사용하여 표층 지점의 10cm, 심층 지점의 40cm에서의 토양수분, 토양장력과 토양온도를, 기상 관측 장비인 ATMOS를 사용하여 태양복사, 강수량, 기온, 풍속, 대기압 등 다양한 기상 요소를, 실시간 클라우드 방식으로 1여 년간 수집한 데이터를 활용한다. 또한, 과거 및 실시간 데이터를 기반으로 LSTM(Long-Short Term Memory) 기법을 사용하여 토양수분 예측 모형을 구축하고, 선행 예측 시간에 따른 모의 정확도를 평가한다. 기상 요소의 누적 등 자료 분석 방법이 표층 및 심층 토양수분 예측에 미치는 영향, 그리고 예측 모형 개선 방향에 대해 토의한다. 실시간 현장 관측 자료 및 인공지능 기반 단기 토양수분 예측 모의 기술은 소규모 유역의 수문순환 분석 및 물리기반 모형의 개선 등 다양한 분야에서 활용할 수 있을 것으로 기대된다.

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Analysis of Hydraulic Passage Efficiency of Ice-Harbor Type Fishway for Flowrate Change (유량변화에 따른 아이스하버식 어도의 수리학적 이동효율 분석)

  • Jo, Jae An;Han, Eun Jin;Kim, Young Do;Baek, Kyong Oh
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.5
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    • pp.1841-1850
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    • 2013
  • The various types of fishways are installed at the multi-functional weirs in the four major rivers to minimize the negative effect due to the construction of the transverse structures. The movable weir was installed at the upstream of the ice-harbor type artificial fishway of the Dalseong weir in the Nakdong river, which can control the fishway flowrate regardless of the river flowrate. The incoming flowrate to the artificial fishway is closely related with the hydraulic characteristics that dominate the fish passage efficiency. Thus, it is crucial to find out the weir operation rule for properly sustaining efficient fish-passage, such as the optimized flowrate. In this study, the FLOW-3D was used to analyze and compare the various hydraulic characteristics associated with the passage efficiency, based upon the given different flowrate, and subsequently provide the optimized flowrate for the fishway movable weir to maintain the best efficient flow condition for the fish-passage.

A Study of Statistical Analysis of Rock Joint Directional Data (암반 절리 방향성 자료의 통계적 분석 기법에 관한 연구)

  • 류동우;김영민;이희근
    • Tunnel and Underground Space
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    • v.12 no.1
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    • pp.19-30
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    • 2002
  • Rock joint orientation is one of important geometric attributes that have an influence on the stability of rock structures such as rock slopes and tunnels. Especially, statistical models of the geometric attributes of rock joints can provide a probabilistic approach of rock engineering problems. The result from probabilistic modeling relies on the choice of statistical model. Therefore, it is critical to define a representative statistical model for joint orientation data as well as joint size and intensity and build up a series of modeling procedure including analytical validation. In this paper, we have examined a theoretical methodology for the statistical estimate and hypothesis analysis based upon Fisher distribution and bivariate normal distribution. In addition, we have proposed the algorithms of random number generator which is applied to the simulation of rock joint networks and risk analysis.

Vibration Characteristics Evaluation According to Natural Periods of Structures and Location of a Sky-bridge (구조물의 고유진동주기 및 스카이브릿지 설치위치에 따른 진동특성평가)

  • Kim, Hyun-Su
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.6
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    • pp.3068-3073
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    • 2013
  • Recently, studies of vibration control performance improvement of tall buildings connected by a sky-bridge have been conducted. In this study, the effect of difference of natural vibration periods of two buildings and install location of a sky-bridge on vibration control performance has been investigated. To this end, 40-story and 50-story building structures were selected as example structures. Analytical models were developed by varying the natural period difference ratio from 1.0 to 1.5. Artificial earthquake load based on KBC2009 was used as an excitation for time history analyses. Based on numerical simulation results, it has been shown that control performance for displacement and velocity of tall buildings connected by a sky-bridge is improved as the difference of natural periods of two buildings increases and the linked story becomes higher. However, in the case of acceleration response, it shows a counter trend compared to displacement and velocity responses.

Effect of Shell Structure of Artificial Lightweight Aggregates on the Emission Rate of Absorbed Water (인공경량골재의 표피층 구조가 흡수된 물의 방출속도에 미치는 영향)

  • Kang, Seung-Gu
    • Journal of the Korean Ceramic Society
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    • v.45 no.11
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    • pp.750-754
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    • 2008
  • The artificial aggregates with dense surface layer (shell) was fabricated and the dependence of water emission rate upon the shell structures was studied. The EAF dust containing many flux components and waste white clay with ignition loss of above 48% were used as for liquid phase and gas forming agents during a sintering process respectively. In addition, the shell structure was modified with various processes and the modification effect on water emission rate was analyzed. The pores under $10{\mu}m$ were found in the sintered artificial light aggregates and disappeared by incorporating to a bigger pore during re-sintering. The water emission rate in an initial step depended on a void content of aggregates filled in a bottle rather than a shell structure. But, after 7 days where the water emission of the aggregate with a shell is above 40%, the shell of aggregates suppressed the water emission. The core of aggregates was exposed and most shell was lost when crushed to smaller size so, the ability for suppressing water emission of the crushed aggregates decreased. The activation energy for the water emission was $3.46{\pm}0.25{\times}10^{-1}$J/mol for the most specimens showing that the activation energy is irrelevant to the pore size distribution and shell structure.

Syngas and Hydrogen Production from $CeO_2/ZrO_2$ coated foam device under concentrated solar radiation (고온 태양열을 이용한 합성가스 및 수소 생산에서 $CeO_2/ZrO_2$가 코팅된 다공성 폼의 영향)

  • Jang, Jong-Tak;Yoon, Ki-June;Han, Gui-Young
    • 한국태양에너지학회:학술대회논문집
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    • 2011.11a
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    • pp.307-313
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    • 2011
  • 금속산화물을 이용한 2단계 산화/환원 반응은 GTL, CTL 의 반응원료인 합성가스 및 수소 생산기술이다. 이 기술은 메탄을 환원제로 사용함으로써 비교적 저온에서 산화/환원 반응을 할 수 있는 장점이 있다. 하지만 반복 사이클의 시연에서 금속산화물의 소결현상으로 인한 활성저하가 이 기술의 문제점 중의 하나이다. 본 연구에서는 2.5 kW Xenon arc lamp 가 설치된 solar simulator를 사용 하였으며, 무기물 다공성 폼 (SiC foam)및 유기물 다공성 폼 (Ni, Cufoam)에 $CeO_2/ZrO_2$ 를 코팅하여 연속적인 합성가스 및 수소 생산 가능성을 알아보았다. 반응 전 후의 $CeO_2/ZrO_2$ 의 결정 구조를 SEM 과 XRD 를 통해 분석하였다.

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Capacity Estimation and System Design of Current Power Generation at the Discharge Channel of Hadong Thermal Power Plant (하동화력발전소 방수로 조류식 발전량 산정 및 시스템 설계)

  • Kang, Keum-Seok;Kim, Ji-Young;Lee, Dae-Soo;Lee, Kwang-Soo
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.06a
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    • pp.509-512
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    • 2006
  • 국내 대형 기력발전단지에서 냉각수로 사용되고 방류되는 해수는 약 150cms로 (100Mwe 당 약 5cms) 약 3,000kW 이상의 수력에너지를 보유하고 있으나, 현재 활용되지 못하고 그대로 해양으로 방류되고 있다. 발전소 방수로는 흐름조건이 비교적 균일하고, 파랑 내습이 없으며 부유사 해조류, 부유물 충돌 등의 문제가 발생하지 않아 자연 해양조건보다 조류력 발전에 매우 유리하나 수심이 낮고, 순환수 계통에의 영향으로 다수의 수차를 설치하기는 어려운 조건을 지니고 있다. 따라서, 인공수로의 균일하고 양호한 흐름조건에 적합한 보다 경제적인 수차를 개발하고, 발전량을 증대하기 위한 수차 배치 기술, 수차 및 발전기 지지구조물의 설계 기술, 계통 연결기술 등을 개발할 필요가 있으며, 이를 위하여 시험용 조류식 발전시스템을 제작하여 수차의 성능 및 전체 발전시스템의 성능을 평가하여 발생되는 문제점을 해결하고자 한다. 본 연구에서는 시험용 조류식 발전시스템을 하동화력발전소 방수로에 적용하기 위하여 현장 특성 분석, 형식 선정, 발전량 산정 등의 시스템 설계를 수행하였다.

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The morphological changes of the beach and dune using by periodical measurements (주기적 지형 측량을 통한 해빈과 해안사구의 지형변화: 충남 보령시 소황사구를 사례로)

  • KANG, Dong Kyun;SEO, Jong Cheol
    • Journal of The Geomorphological Association of Korea
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    • v.19 no.2
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    • pp.69-79
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    • 2012
  • The aim of this study is to analyze the mid-term changes of beach and dune morphology at Sohwang beach, Korea using by Total Station. Measurements executed 4 times during two year. Based on ArcInfo as point cloud obtained through precise measurement data by Total Station, alteration of beach and dune was analyzed at DEM, of which cell size is about 1m. Since these artificial constructions have influenced current systems of this region, the large-scale sand movements above mentioned have occurred around the jetty and the sea-wall. There occurred sedimentation in the north of the Jetty and erosion in the south of the Jetty, which is installed at the central part of object area. The direction of recent topographic development does not coincide with that of wind, and, rather, topographic changes occurred mainly at beaches and dunes due to the transformation of coastal water flow caused by artificial structure nearby. If precise measurement is conducted periodically, and long term monitoring is carried out by installing equipment measuring movement pattern of sediment around artificial structure, cause of topographic change around the object area could be discovered.