• Title/Summary/Keyword: Fines

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A study on the design of data bus(EFbus) for factory automation (공장자동화용 데이타 버스(EFbus)의 설계에 관한 연구)

  • 이전우;황선호;김현기;이혁희;채영도
    • 제어로봇시스템학회:학술대회논문집
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    • 1990.10a
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    • pp.623-628
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    • 1990
  • This paper describes the design of EFbus(ETRI Fieldbus), EFbus was designed from the interim results of international Fieldbus standardization in IEC (International Electrotechnical Commission) and proposals of many companies. The design was performed and described on the basis of three layered architecture. Application layer S/W runs on IBM PC and provides services which is similar ED MMS in MAP to user application Data linklayer runs on Intel's iDCX96 real time executive and uses centralized media accesscontrol method. Physical layer uses Manchester encoding & decoding, twisted pair fines and RS485 electrical standard.

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Slope Sedimentation and Organic Carbon Content in the Late Quaternary West Florida Slope Sediments

  • Lee, Eun-Il;Park, Soo-Chul
    • Journal of the korean society of oceanography
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    • v.34 no.3
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    • pp.144-150
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    • 1999
  • Slope sedimentation on the modern west Florida continental margin is controlled by pelagic carbonate accumulation and off-shelf sedimentation of neritic carbonates and terrigenous fines. Production and deposition of pelagic carbonates by planktonic foraminifera and coccoliths have played a significant role in the total slope sedimentation and are mainly promoted by sea-surface productivity. Organic carbon data reflect the relatively high biological productivity in surface waters, indicating high accumulation of biogenic calcareous sediments. The surface-water productivity in the study area is supported by the relation among microfossil assemblages, carbonate mineralogy and sedimentary organic carbon.

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Elutriation and Production of Fines in a Fluidized Bed Coal Combustor (석탄유동층연소로에서 분진 발생 및 배출 특성)

  • 장현태;이종일
    • Journal of the Korean Society of Safety
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    • v.11 no.2
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    • pp.96-101
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    • 1996
  • The effects of coal type and mixing fraction of coal on attrition and elutriation were studied in a 15. 5cm diameter fluidized bed coal combustor. The domestic low-grade anthracite coal with heating value 2010kcal/kg and the imported bituminous coal from Australia with heating value of 6520kcal/kg were used as coal sample. It was found from the experimental that the elutriation rate inclosed with an increseing anthracite mixing fraction. The size of elutriated particle had a very wide distribution was found in this experiment. The mean size of elutriated particle increased with decreaseing anthracite mixing fraction.

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A Study on the Analysis Method of Soil Dust Included in the Aggregate Fines (골재 미립분에 포함된 토분의 분석방법 고찰)

  • Min, Tae-Beom;Kim, In;Lee, Jae-Sam;Baek, Chul-Seoung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.05a
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    • pp.257-258
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    • 2023
  • As a result of examining research contents related to soil excretion being studied in Korea, there are five methods for soil excretion testing. As a result of analyzing the correlation between each test method and concrete compressive strength, the chemical test method and the Methylene blue test showed a high correlation index.

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Experimental Study on the Effect of Drilling Fluid with Different Mix Designs for Bore Hole Collapse Prevention (시추 안정액 배합설계에 따른 공벽 붕괴방지 효과에 관한 실험적 연구)

  • Yoo, Chung-Sik;Choi, Jung-Hyuk;Han, Yun-Su
    • Journal of the Korean Geotechnical Society
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    • v.31 no.1
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    • pp.15-24
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    • 2015
  • This paper presents the results of a reduced-scale physical model investigation into the effect of drilling fluid with different mix designs for bore hole collapse prevention. The bore hole collapse prevention mechanism for the bentonite based drilling fluid was first discussed together with the effect of conditioning with different additives on engineering characteristics of bentonite based drilling fluid. Reduced-scale model tests were then carried out considering field procedures for cases with a decomposed granitic soil with 20% fines and a sand with various drilling fluids with different mix designs. The results indicated that the addition of polymer to the bentonite based drilling fluid decreases the amount of drilling fluid injected, the drilling fluid infiltration thickness and increases the final depth of excavation. Also revealed is that the effect of polymer on the performance of drilling fluid is more pronounced in the decomposed granite soil with 20% fines than the sand. Practical implications of the findings from this study are discussed in great detail.

Analysis on Reduction Effect Factors of Occupational Fatalities in Construction Industry - Focusing on Agency Factors - (건설업의 산업재해 사고사망자 감소 영향요인 분석 - 기관 행정요인을 중심으로 -)

  • Song, Byungchoon;Won, Jeong-Hun
    • Journal of the Korean Society of Safety
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    • v.35 no.2
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    • pp.47-54
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    • 2020
  • The purpose of this study is to determine whether the variables of the agency factors affected the number of occupational fatalities in the construction industry in order to determine whether there is a relationship between the number of occupational fatalities occurring at the construction sites and the agency. The considered agencies are KOSHA (Korea Occupational Safety and Health Agency) and MOEL (Ministry of Employment and Labor). The variables of two agency factors are classified as follows: the variables of two agency factors are the number of employees, budget amounts, technical support and guidance for construction sites of KOSHA, and the number of labor inspectors, the number of inspection and oversight workplace, the number of criminally punished construction sites and fines levied on them in the industrial accident prevention departments of Regional Employment and Labor Office. The multiple regression analysis was conducted to determine the effect of two agency factors on the total number of occupational fatalities in the construction industry. The policy implications derived from this study are that, in order to reduce the fatalities of construction sites by KOSHA, the appropriate level of increased budget for KOSHA must be secured every year. In addition, the amount of fines levied on construction sites by the labor inspector in the industrial accident prevention departments of Regional Employment and Labor Office reduces the occupational fatalities at the construction sites.

The Effect of Pulp type and Initial Calendering on the Characteristics of Recycled Fiber (펄프의 종류 및 초기 캘린더링이 리사이클 섬유의 특성에 미치는 영향)

  • 손상돈;안병준;백기현
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.31 no.4
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    • pp.41-48
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    • 1999
  • This study was intended to investigated the effect of pulp type and intital calendering on the properties of recycled fiber. As the number of recycling is increased, at least by the fourth recycling , the freeness of the SW-BKP and HW-BKP increased. And then that decrease after the fifth recycling. Especially the freeness of CTMP increased more rapidly than any other pulp in first recycling. And there was no difference of freeness in all kind of pulp by initial calendering . The speed of dewatering in making sheet consistetly became slow by proceeding recycling on condition of all calendering. and the order of the speed of dewatering was as followed. CTMP>HW-BKP>SW-BKP. However in case of HW-BKP, which was low -yield pulp, the tendency of the speed of dewatering was similar to that of CTMP which was high-yield pulp and had high content lignin . There was no change of fiber length and no effect of calendering by recycling of HW-BKP and CTMP. Howeverfiber length of SW-BKP generally decreased, especially in calendering of high temperature and high pressure conditions. The WRV of SW-BKP diminished by proceeding recycling but that of HW-BKP and CTMP diminished in the first recycling and then there was no change of the WRV of HW-BKP and CTMP. The contents of fines of HW-BKP consistently decreased by the fourth recycling and then increased in the fifth recycling . On the other hand there was no tendency in the content of fines of SW-BKP and CTMP by the number of recycling.

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A Study on the Liquefaction Behavior of Bottom Ash (Bottom Ash의 액상화 저항특성 연구)

  • Yoon, Won-Sub;Chae, Young-Su
    • Journal of the Korean Geotechnical Society
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    • v.27 no.6
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    • pp.63-79
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    • 2011
  • In this study relative density tests of bottom ash and standard sand were carried out. And cyclic triaxial tests for samples with the relative density of 40%, 55%, and 70% were carried out on the basis of the test results. Cyclic triaxial tests were also conducted for fines content with 55% relative density. Residual samples were divided into No.40, No.60, No.60, and No.100, and No.200. In order to avoid crashing that can happen when compaction of the sample is initiated, bottom ash was crushed using the a compact mold. In consideration of the crushing characteristics of each residual samples, the fragmentation rate increased up to 30%, which led to the adjustment of fine-grained amount to 10%, 20%, and 30%. Through the repative triaxial test in accordance with the relative density, resistant characteristics of the liquefaction of bottom ash was analyzed. Test results show that, crushing strength of bottom ash was smaller than that of standard sand, resulting in different liquefaction behavior characteristics. And we could find fines content with maximum resistant characteristics of the liquefaction.

The Friction Coefficients of Interfaces between Weathered Granite Soil and Reinforcements (화강토와 보강재 경계면에서의 마찰계수에 관한 연구)

  • 김상규;이은수
    • Geotechnical Engineering
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    • v.12 no.2
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    • pp.107-114
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    • 1996
  • A series of shear tests is performed to measure friction coefficients of the interface between different reinforcements and weathered granite soils. The reinforcements tested are smooth steel strip, Paraweb(friction tie) and geotextile with rough surface, while the weathered granite soils are composed of different, grain size distribution. Soils are compacted with the energy of 95% modified AASHTO and fully saturated before testing to simulate the worst site condition. Because of characteristics of the direct shear apparatus, shear strength is obtained in terms of drained condition. Test results show that the more fines the soils contain, the larger ratio of friction coefficient ($\mu=\frac{tan{\delta}}{tan{\Psi}}$) is obtained. Also the ratios are much higher for the Friction tie and the geotextile compared to the smooth steel strip. Those suggest that even weathered granite soils with 36% fines are possible to use as backfill of reinforced earth structures for the two reinforcements when a drainage system is provided.

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A Study on the Book Circulation Rules of Public Library in Korea (전국 공공도서관 대출규정 조사 연구)

  • Yoon, Hee-Yoon
    • Journal of Korean Library and Information Science Society
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    • v.51 no.1
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    • pp.349-372
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    • 2020
  • Regardless of East and West, public libraries provide various services to their communities based on collections. The decisive reason for local residents to visit public libraries is to access and borro w collections. An important condition maintenance to support these activities and services is the library circulation(usage) rules. Therefore, this study compared and analyzed the library membership, maximum loan items, loan period, loan reserve and renewal, overdue fines, disposal of lost and damaged items, loan of non-book materials, loan regulations for the disabled. And after checking the relative deviations in connection with the library cases of major developed countries, this study proposed the improvement of circulation rules. In order to minimize public complaints about circulation services and to relieve the burden of practitioners such as personnel disadvantage due to administrative audit for non-recoverable ite ms, public libraries must faithfully rearrange the circulation rules and regulations.