• 제목/요약/키워드: long term performance

검색결과 2,573건 처리시간 0.031초

Experimental study on long-term behaviour of CFRP strengthened RC beams under sustained load

  • Ahmed, Ehsan;Sobuz, Habibur Rahman
    • Structural Engineering and Mechanics
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    • 제40권1호
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    • pp.105-120
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    • 2011
  • The strengthening and rehabilitation of reinforced concrete structures with externally bonded carbon fibre reinforced polymer (FRP) laminates has shown excellent performance and, as a result, this technology is rapidly replacing steel plate bonding techniques. This paper addresses this issue, and presents results deals with the influence of external bonded CFRP-reinforcement on the time-dependent behavior of reinforced concrete beams. A total of eight reinforced concrete beams with cracked and un-cracked section, with and without externally bonded CFRP laminates, were investigated for their creep and shrinkage behavior. All the beams considered in this paper were simply supported and subjected to a uniform sustained loading for the period of six months. The main parameters of this study are two types of sustained load and different degrees of strengthening scheme for both cracked and un-cracked sections of beams. Both analytical and experimental work has been carried out on strengthened beams to investigate the cracking and deflection performance. The applied sustained load was 56% and 38% of the ultimate static capacities of the un-strengthened beams for cracked and un-cracked section respectively. The analytical values based on effective modulus method (EMM) are compared to the experimental results and it is found that the analytical values are in general give conservative estimates of the experimental results. It was concluded that the attachment of CFRP composite laminates has a positive influence on the long term performance of strengthened beams.

Improvement in Long-Term Stability and Photovoltaic Performance of UV Cured Resin Polymer Gel Electrolyte for Dye-Sensitized Solar Cell

  • Park, Geun Woo;Hwang, Chul Gyun;Jung, Jae Won;Jung, Young Mee
    • Bulletin of the Korean Chemical Society
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    • 제33권12호
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    • pp.4093-4097
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    • 2012
  • We introduced a new UV-cured resin polymer gel as an electrolyte for dye-sensitized solar cells (DSSCs) that is cured with UV irradiation to form a thin film of UV-cured resin polymer gel in the cells. The gel film was characterized and its potential for use as an electrolyte in DSSCs was investigated. This new UV-cured resin polymer gel was successfully applied as a gel polymer electrolyte in DSSCs overcoming the problems associated with the liquid electrolytes in typical DSSCs. The effect of ${\gamma}$-butylrolactone (GBL) on the long-term stability and photovoltaic performance in DSSCs using this UV-cured resin polymer gel electrolyte was also investigated. The results of the energy conversion efficiency, ionic conductivity and Raman spectra of the UV-cured resin polymer gel electrolyte with the addition of 6 wt % GBL to the UV-cured resin polymer electrolyte showed good long-term stability and photovoltaic performance for the DSSCs with the UV-cured polymer gel electrolyte.

천연 항균물질을 이용한 황토모르타르의 항곰팡이 성능 평가 (Antifungal Performance of Hwangtoh Mortars with Natural Antifungal Substances)

  • 소형석;김정우;이보람;소승영
    • 콘크리트학회논문집
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    • 제27권1호
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    • pp.75-83
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    • 2015
  • 본 연구는 다양한 천연물계 항균물질로부터 추출된 추출액(extract)들의 자체 항곰팡이 성능을 평가하고, 이를 적용한 항균모르타르의 항곰팡이 성능과 그 지속성능, 그리고 항균성능 등에 대해 종합적으로 고찰함으로써 효율적인 건축물 내 항균대책 및 친환경 항균 건자재(모르타르 포함) 개발을 위한 기초적 자료를 제공하고자 수행하였다. 시험결과, 마조람 추출액 및 이를 적용한 항균모르타르의 항곰팡이 성능은 현재 널리 사용되고 있는 유기계 화학 항곰팡이제 및 이를 적용한 모르타르와 동등수준의 높은 항곰팡이 성능을 나타내었다. 특히 마조람 추출액 5% 혼입 모르타르는 장기 항곰팡이 성능뿐 아니라 대장균, 녹농균 및 황색포도상구균에 대한 항균성능에서도 뛰어나 그 활용가능성이 크게 기대되었으며, 향후 이에 대한 보다 상세한 검토가 요구된다.

중국 진출 한국 제조기업의 현지 장애요인이 경영성과에 미치는 영향 연구 (A Study on the Factors Barrier Determining the Performance of Korean Manufacturing Firms in China)

  • 백은영;구종순
    • 통상정보연구
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    • 제11권3호
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    • pp.311-335
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    • 2009
  • This study investigates the factors barrier the performance of Korean manufacturing firms in China. Also an empirical data use the field survey of Korean manufacturing firms in China. as a result, First, we find that employment-cost factor, that is rising labor costs, a change of occupation is an effect the performance of Korean manufacturing firms in China. Second, business beginning year and by 7 region factor is very significant on the performance of Korean FDI firms in china. And then, Korean corporate investment in China is a desirable form of long-term investment shall be determined. also we know that regions of China, differentiated investment approach is effective. finally, The result shows that FDI to China is need of the long term plan, and In actual use, these FDI should be applied flexibly in china business environment.

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Solid Oxide Fuel Cells for Power Generation and Hydrogen Production

  • Minh, Nguyen Q.
    • 한국세라믹학회지
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    • 제47권1호
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    • pp.1-7
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    • 2010
  • Solid oxide fuel cells (SOFCs) have been under development for a variety of power generation applications. Power system sizes considered range from small watt-size units (e.g., 50-W portable devices) to very large multi-megawatt systems (e.g., 500-MW base load power plants). Because of the reversibility of its operation, the SOFC has also been developed to operate under reverse or electrolysis mode for hydrogen production from steam (In this case, the cell is referred to as solid oxide electrolysis cell or SOEC.). Potential applications for the SOEC include on-site and large-scale hydrogen production. One critical requirement for practical uses of these systems is long-term performance stability under specified operating conditions. Intrinsic material properties and operating environments can have significant effects on cell performance stability, thus performance degradation rate. This paper discusses potential applications of the SOFC/SOEC, technological status and current research and development (R&D) direction, and certain aspects of long-term performance degradation in the operation of SOFCs/SOECs for power generation/hydrogen production.

옥외 장기폭로에 따른 UHPC 패널의 표면 특성 평가 연구 (A study on the Evaluation of Surface Properties of UHPC Panels following long-term outdoor exposure)

  • 김태익;최병걸;박용규;최상훈;윤기원;이대식
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2022년도 봄 학술논문 발표대회
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    • pp.176-177
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    • 2022
  • In this study, surface performance evaluation was conducted according to the fiber and surface finishing technique of the exterior material using Ultra High Performance Concrete(UHPC), whitch is spotlighted as a highly durable exterior material. As a result of outdoor exposure, the initial performance of the UHPC Panel using organic fibers was maintained without being affected by the surface finishing technique. In the specimen using steel fiber, the surface performance was maintained when the water repellent treatment was performed in the plain specimen, but fiber corrosion occurred in the specimen to which the surface finishing technique was applied.

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Assessment of long-term working memory by a delayed nonmatch-to-place task using a T-maze

  • Kim, Jung-Eun;Choi, Jun-Hyeok;Kaang, Bong-Kiun
    • Animal cells and systems
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    • 제14권1호
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    • pp.11-15
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    • 2010
  • Long-term working memory (LTWM) is a subdivision concept of working memory and indicates the enhancement of performance in a working memory task. LTWM has been shown in humans who have been engaged in a specific task requiring working memory over a long time. However, there is very little understanding of the exact mechanism of LTWM because of limitations of experimental methods in human studies. We have modified the standard T-maze task, which is used to test working memory in mice, to demonstrate LTWM in an animal model. We observed an enhancement of performance by repeated experience with the same working memory load in mice, which can be regarded as an LTWM. This effect seems to depend on the condition wherein a delay was given. This task may be a good experimental protocol to assess LTWM in animal studies.

Seasonality and Long-Term Nature of Equity Markets: Empirical Evidence from India

  • SAHOO, Bibhu Prasad;GULATI, Ankita;Ul HAQ, Irfan
    • The Journal of Asian Finance, Economics and Business
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    • 제8권4호
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    • pp.741-749
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    • 2021
  • The research paper endeavors to investigate the presence of seasonal anomalies in the Indian equity market. It also aims to verify the notion that equity markets are for long-term investors. The study employs daily index data of Sensex, Bombay Stock Exchange, to understand its volatility for the period ranging from January 2001 to August 2020. To analyze the seasonal effects in the stock market of India, multiple regression techniques along with descriptive analysis, graphical analysis and various statistical tests are used. The study also employs the rolling returns at different time intervals in order to understand the underlying risks and volatility involved in equity returns. The results from the analysis reveal that daily and monthly seasonality is not present in Sensex returns i.e., investors cannot earn abnormal returns by timing their investment decisions. Hence, the major finding of this study is that the Indian stock market performance is random, and the returns are efficient. The other major conclusion of the research is that the equity returns are profitable in the long run providing investors a hope that they can make gains and compensate for the loss in one period by a superior performance in some other periods.

A 12-year long-term study on the external deformation behavior of Geosynthetic Reinforced Soil (GRS) walls

  • Won, Myoung-Soo;Lee, O-Hyeon;Kim, You-Seong;Choi, Se-Kyung
    • Geomechanics and Engineering
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    • 제10권5호
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    • pp.565-575
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    • 2016
  • Geosynthetics reinforced soil (GRS) walls constructed on weak grounds may change in both the horizontal earth pressure and deformation on wall facing. However, only few studies were done in the literature to measure and analyze the horizontal external deformation behavior of GRS walls constructed on soft grounds for a long period of time. The present study describes the external deformation behavior of GRS walls observed for 12-year long-term performance. The horizontal deformation of the geosynthetics-wrapped-facing GRS walls shows a passive behavior along one third of the wall height, from top going downwards, and active behavior for the rest of the wall height. Even if the geogrid and nonwoven geotextiles are exposed directly to sunlight and rainfalls in a span of 12 years, they have functioned well as wall facing. Therefore, the geosynthetic reinforcement material is strong enough to resist ultraviolet rays.

An Approach for Stock Price Forecast using Long Short Term Memory

  • K.A.Surya Rajeswar;Pon Ramalingam;Sudalaimuthu.T
    • International Journal of Computer Science & Network Security
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    • 제23권4호
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    • pp.166-171
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    • 2023
  • The Stock price analysis is an increasing concern in a financial time series. The purpose of the study is to analyze the price parameters of date, high, low, and news feed about the stock exchange price. Long short term memory (LSTM) is a cutting-edge technology used for predicting the data based on time series. LSTM performs well in executing large sequence of data. This paper presents the Long Short Term Memory Model has used to analyze the stock price ranges of 10 days and 20 days by exponential moving average. The proposed approach gives better performance using technical indicators of stock price with an accuracy of 82.6% and cross entropy of 71%.