• 제목/요약/키워드: WRA

검색결과 30건 처리시간 0.024초

고성능 감수제를 첨가한 폴리머 시멘트 모르타르의 강도 특성 (Strength Properties of Polymer-Modified Mortar with High-Range Water- Reducing Agents)

  • 이윤수;주명기
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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    • pp.811-815
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    • 2003
  • The effects of high-range water-reducing agent (WRA) content and polymer-cement ratio on the strength properties of autoclaved SBR-modified mortars with WRA are examined. As a result, the flexural strength of the autoclaved SBR-modified mortars with WRAs tends to increase with increasing WRA content and polymer-cement ratio, and reaches a maximum at a WRA content of 2.0%. The compressive strength of the autoclaved SBR-modified mortars with WRAs is inclined to increase with increasing WRA content and polymer-cement ratio, and reaches a maximum at a WRA content of 2.0% and a polymer-cement ratio of 10%. From the test results, the addition of the WRAs is effective for improving strength properties of the autoclaved SBR-modified mortars.

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AE 감수제 과다첨가가 콘크리트의 물리적 특성에 미치는 영향 (Influence of Over-Added AE Water Reducing Agent on Physical Properties of the Concrete)

  • 한천구;한민철;이동규
    • 한국건축시공학회지
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    • 제8권1호
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    • pp.91-96
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    • 2008
  • This study is to investigate the influence of the over-added chemical agents, such as water reducing agent(WRA) and AE water reducing agent(AEWRA), on the physical properties of concrete to estimate the degree of damage due to over-added chemical agents. For the fresh concrete, slump and slump flow increased with the increase of WRA and AEWRA as expected. Material segregation phenomenon was observed with the over dosage of lignin based AEWRA about 4 times larger than recommended dosage. The over dosage of AE water reducing agent about 4 times larger than recommended dosage resulted in an increase of air contents remarkably. The set retardation occurred greatly with the increase of AEWRA and WRA. For the properties of the hardened concrete corresponding to the over dosage of AEWRA, it is found that compressive strength of over added AEWRA and WRA concrete are much smaller than those of base and recommended dosage concrete proportionally due to associated increasing air content.

Performance Improvement of Nonformaldehyde Wrinkle Resistant Finished Cotton Fabrics Treated with Dialdehydes

  • Park, Hyung-Min;Kim, Yong-Min
    • Fibers and Polymers
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    • 제2권4호
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    • pp.190-195
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    • 2001
  • Additives, such as sodium perborate and borax, were examined in dialdehyde wrinkle resistant finishing of cotton. Results indicated that the whiteness index(WI) of cotton treated with dialdehyde and additive showed about 90% of WI of the untreated cotton but with decrease in wrinkle recovery angle (WRA) due to inhibition effect of these additives. Effect of additive on the WRA reduction was more prominent with glutaraldehyde than with glyoxal. Reduction in WRA of cotton treated with both dialdehydes and boron compound was minimized by simultaneous addition of formic acid in the bath. Addition of formic acid was also generally beneficial in maintaining WI retentions after 8 months storage. Furthermore, boron compounds were also effective in improving retentions of mechanical properties. By FTIR analysis the residual aldehyde group was detected on the dialdehyde-finished cotton, whereas no peak was shown by addition of boron compounds. This suggested that the residual aldehyde group was a main cause of fabric yellowing on the dialdehyde-finished cotton. Dialhehyde with boron compound, therefore, can be used to replace a conventional formaldehyde-containing wrinkle resistant finishing of cotton.

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Noise Robust Automatic Speech Recognition Scheme with Histogram of Oriented Gradient Features

  • Park, Taejin;Beack, SeungKwan;Lee, Taejin
    • IEIE Transactions on Smart Processing and Computing
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    • 제3권5호
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    • pp.259-266
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    • 2014
  • In this paper, we propose a novel technique for noise robust automatic speech recognition (ASR). The development of ASR techniques has made it possible to recognize isolated words with a near perfect word recognition rate. However, in a highly noisy environment, a distinct mismatch between the trained speech and the test data results in a significantly degraded word recognition rate (WRA). Unlike conventional ASR systems employing Mel-frequency cepstral coefficients (MFCCs) and a hidden Markov model (HMM), this study employ histogram of oriented gradient (HOG) features and a Support Vector Machine (SVM) to ASR tasks to overcome this problem. Our proposed ASR system is less vulnerable to external interference noise, and achieves a higher WRA compared to a conventional ASR system equipped with MFCCs and an HMM. The performance of our proposed ASR system was evaluated using a phonetically balanced word (PBW) set mixed with artificially added noise.

Implementations of Geographic Information Systems on Sewage Management for Water Resources Protection

  • Wu, Mu-Lin;Chen, Chiou-Hsiung;Chou, Wen-Shang;Huang, Hsiu-Lan
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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    • pp.1188-1190
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    • 2003
  • Taipei Watershed Management Bureau (WRATB) is a government agency entitled for water resources protection at two major watersheds in order to provide drinking water for about four millions population in Taipei on a sustainable basis. At WRATB, there are two major public sewage treatment facilities which can convert sewage in each watershed into an acceptable state before they were discharged into rivers. More than 82% of household wastewater have been collected and treated by the two public sewage systems. However, households at remote area still need more effective sewage management prescriptions. The objective of this paper is to implement geographic information systems in order to provide more effective approaches that sewage management can be easier and cost effective. ArcIMS was implemented for Internet browsing and map server of those sewage facilities on personal computers, laptop computers. In the open field, ArcPAD was implemented with personal digital assistant (PDA) such that compact flash type's global positioning systems (GPS) and digital camera can be utilized with PDA. All sewage facilities digital files were convert into ArcMap format files. MapObjects and visual BASIC were used to create sewage application modules to meet every single technician personal flavor. ASP.NET was implemented for Internet database manipulations of all sewage databases. Mobile GIS was the key component of GIS applications in the open field for sewage management on a basis of house by house. Houses at remote area, which can not cover by the two public sewage systems, were managed by PDA and laptop computers with GPS and digital camera. Sewage management at Taipei Watershed Management Bureau is easier both in the open field and in the office. Integration of GPS, GIS, and PDA makes sewage management in the open field much easier. ArcIMS, MapObjects, ASP.NET and visual BASIC make sewage management can be done in the office and over Internet.

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농산물 저온유통용 내수 골판지 상자의 제조(제2보) - 골판지의 내수 및 내습성 향상을 위한 약품 적용 방법 - (Manufacture of Water-Resistant Corrugated Board Boxes for Agricultural Products in the Cold Chain System(II) - Application Methods of Chemicals for Improving Water and Moisture Resistance of Corrugated Boards -)

  • 조중연;민춘기;신준섭
    • 한국펄프종이공학회:학술대회논문집
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    • 한국펄프종이공학회 2004년도 춘계학술발표논문집
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    • pp.192-210
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    • 2004
  • Application methods of chemicals were investigated tn minimize strength reduction of corrugated boards under the high humidity environment encountered in the cold chain system. Starch insolubilizers were introduced in the starch solution preparation of the Stain hall method and their insolubilization effect of starch binder were estimated. The performance of water repellent agents(WRA) and moisture proof agents(MPA) were evaluated in terms of water and moisture resistance. And effects of the combination of the chemicals and the coating method were also examined. Addition of the polyamine polyamide insolubilizer to the main part in the Stain hall process improved the binding force and water resistance of starch, which contributed to minimize the strength reduction of paper under the high humidity environment. AZC and Glyoxal type insolubilizers could not be used in the experiment due to an excessively increased viscosity of starch solution and the poor stability. Conventional WRA treatment to the base paper enhanced water and moisture resistance very slightly even though water repellency of the paper reached R10 by the treatment. MPA showed excellent performance than WRA not only in water and moisture resistance but in water repellency. Double coating on paper with MPA was more effective than the single coating at the same coating weight. A newly developed MPA showed excellent performance and runnability only by a single coating instead of a double coating.

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도로터널 소요환기량 산정기준 변화에 따른 영향 분석 (A study on the effects of changes in the estimating criteria for ventilation requirements in road tunnels)

  • 김효규;이창우
    • 한국터널지하공간학회 논문집
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    • 제21권6호
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    • pp.779-793
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    • 2019
  • 소요환기량은 터널단면을 결정하기 위한 기초적인 자료로, 터널 내 환기 시스템을 결정하기 위한 주요한 요소이다. 소요환기량은 터널 내 교통량 자료에 기초하고 있으며, 차량으로부터 배출되는 오염물질량과 터널 내 허용농도 기준에 의해 결정된다. 본 논문에서는 처음으로 국내 기준이 한국도로공사에 의하여 규정된 1997년 이후 20년간 변화한 도로터널 환기설계기준을 검토하고 최근의 환경부 '제작차 배출허용기준'과 세계도로협회(WRA) 2019년 설계권고기준 등을 바탕으로, 터널의 특성, 특히 길이 및 종단경사를 고려하여 소요환기량 차이 및 영향을 비교분석하였다.

농산물 저온유통용 내수 골판지 상자의 제조(제2보) - 골판지의 내수 및 내습성 향상을 위한 약품 적용 방법 - (Manufacture of Water-Resistant Corrugated Board Boxes for Agricultural Products in the Cold Chain System(II). -Application Methods of Chemicals for Improving Water and Moisture Resistance of Corrugated Boards-)

  • 조중연;민춘기;신준섭
    • 펄프종이기술
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    • 제36권2호
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    • pp.60-69
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    • 2004
  • Application methods of chemicals were investigated to minimize strength reduction of corrugated boards under the high humidity environment encountered in the cold chain system. Starch insolubilizers were introduced in the starch solution preparation of the Stein hall method and their insolubilization effect of starch binder were estimated. The performance of water repellent agents(WRA) and moisture proof agents(MPA) were evaluated in terms of water and moisture resistance. And effects of the combination of the chemicals and the coating method were also examined. Addition of the polyamine polyamide insolubilizer to the main part in the Stein hall process improved the binding force and water resistance of starch, which contributed to minimize the strength reduction of paper under the high humidity environment. AZC and Glyoxal type insolubilizers could not be used in the experiment due to an excessively increased viscosity of starch solution and the poor stability. Conventional WRA treatment to the base paper enhanced water and moisture resistance very slightly even though water repellency of the paper reached R10 by the treatment. MPA showed excellent performance than WRA not only in water and moisture resistance but in water repellency. Double coating on paper with MPA was more effective than the single coating at the same coating weight. A newly developed MPA showed excellent performance and runnability only by a single coating instead of a double coating.

Implementations of Remote Sensing, GIS, and GPS for Water Resources and Water Quality Monitoring

  • Wu, Mu-Lin;Chen, Chiou-Hsiung;Liu, Shiu-Feng;Wey, Jiun-Sheng
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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    • pp.1191-1193
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    • 2003
  • Water quantity and quality monitoring at Taipei Watershed Management Bureau (WRATB) is not only a daily business but also a long term job. WRATB is responsible for providing high quality drinking water to about four millions population in Taipei. The quality of drinking water provided by WRATB is among one of the best in Taiwan. The total area is 717 square kilometers. The water resource pollution is usually divided into two categories, point source pollution and nonpoint source pollution. Garbage disposal is the most important component of the point source pollution, especially those by tourist during holidays and weekends. Pesticide pollution, fertilizer pollution, and natural pollution are the major contributions for nonpoint source pollution. The objective of this paper is to implement remote sensing, geographic information systems, and global positioning systems to monitor water quantity and water quality at WRATB. There are 12 water quality monitoring stations and four water gauge stations at WRATB. The coordinates of the 16 stations were determined by GPS devices and created into the base maps. MapObjects and visual BASIC were implemented to create application modules for water quality and quantity monitoring. Water quality of the two major watersheds at WRATB was put on Internet for public review monthly. The GIS software, ArcIMS, can put location maps and attributes of all 16 stations on Internet for general public review and technical implementations at WRATB. Inquiry and statistic charts automatic manipulations for the past 18 years are also available. Garbage disposal by community and tourist were also managed by GIS and GPS. The storage, collection, and transportation of garbage were reviewed by ArcMap file format. All garbage cart and garbage can at WRATB can be displayed on the base maps. Garbage disposal by tourist during holidays and weekends can be managed by a PDA with a GPS device and a digital camera. Man power allocation for tourist garbage disposal management can be done in an integration of GIS and GPS. Monitoring of water quality and quantity at WRATB can be done on Internet and by a PDA.

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