• 제목/요약/키워드: Sand addition

검색결과 697건 처리시간 0.03초

CSG 재료의 강도특성에 관한 연구 (Strength Characteristics of CSG material)

  • 박한규;김기영;조성은;전제성
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2005년도 춘계 학술발표회 논문집
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    • pp.619-626
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    • 2005
  • This work aims at studing the stress-strain-strength behavior of an CSG(cemented sand and gravel) materials. An analysis of the mechanical behavior of the CSG is performed from the interpretation of results by unconfined compression test, large triaxial compression test in which the influence of both the degree of cementation and age. For CSG, It was concluded that the characterristics of compression are direct measurment of the degree of cementation and age. In addition, hyperbolic model is adopted to express the relation between elastic moduli and cementation, age, confined stress in small strain. The results of the test show that clear correlation with each other

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수직 밀페형 지증 열교환기용 뒤채움재의 열전도 및 점도특성 연구 (Experimental Study on Thermal Conductivity and Viscosity of Grouts for Backfilling Ground Heat Exchanger)

  • 최항석;이철호;길후정;최효범;우상백
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2007년도 추계학술대회 논문집
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    • pp.529-532
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    • 2007
  • In order to characterize the thermal conductivity and viscosity of grout materials used for backfilling ground heat exchangers, nine bentonite grouts and cement grouts being adapted in the United State have been considered in this study. The bentonite grouts indicate that the thermal conductivity and viscosity increase with the content of bentonite or filler (silica sand). In addition, material segregation can be observed when the viscosity of grout is relatively low. The saturated cement grouts appear to possess much higher thermal conductivity than the saturated bentonite grouts, and the reduction of thermal conductivity in the cement grouts after drying specimens is less than in case of the bentonite grouts. Maintaining the moisture content of grouts is a crucial factor in enhancing the efficiency of ground heat exchangers.

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복합오염물질제거를 위한 현장반응층 이용에 관한 연구

  • 조현희;박재우
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 2003년도 추계학술발표회
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    • pp.168-171
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    • 2003
  • This research was conducted to assess the performance of the mixed reactive materials with sand, iron filings, and HDTMA-bentonite for trichloroethylene (TCE) and chromate removal under controlled groundwater flow conditions. TCE and chromate removal rates with the mixtures of iron filing/HDTMA-bentonite were highest among four columns due to reduction by iron filings and sorption by HDTMA-bentonite. The greater capacity of the mixed iron filing/HDTMA-bentonite compared HDTMA-bentonite was due to an enhanced chromate reduction in addition to chromate sorption. The presence of chromate caused greater inhibition of TCE removal in the column with iron filings, while the presence of TCE caused less inhibition of TCE. Also, nitrate caused the decrease in TCE removal relative to chloride. Nitrate ions may also significantly affect TCE reduction rates by competing for electrons with the chlorinated compounds. The anion and co-existed contaminants competing effects should be considered when designed permeable reactive barriers (PRBs) composed of zero valent iron for field applications to remediate TCE and chromate.

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약물이행과 관련된 국내 선행연구 고찰 (Review of Studies about Medication Adherence in Korea)

  • 유승희;강정희
    • 한국보건간호학회지
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    • 제29권2호
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    • pp.285-297
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    • 2015
  • Purpose: The purpose of this study was to analyze published studies on medication adherence in Korea. Methods: The studies were identified and data were collected from Oct. to Nov. 2014 through the RISS, KISS, NDSL, and Nanet websites. Key words including medication adherence and medication compliance were used. A total of 37 published studies were reviewed using criteria developed by researchers. Results: Studies published and associated with adherence have increased since 2010. Several instruments have be enused to date however, there is no critical standard regarding medication adherence. In addition, various interventions are available and have positive effects but the main concept is also deferent with adherence and compliance. Conclusion: There sults show that research related to adherence has actively increased. How ever there are various concepts, method sand standard. Therefore more studies are required in the future for development of a unified concept, methods and standards for adherence for future.

Redescription of the Korean sandlance Hypoptychus dybowskii from Korea

  • Kwun, Hyuck Joon;Yim, Mi-Jin
    • Fisheries and Aquatic Sciences
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    • 제21권9호
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    • pp.20.1-20.3
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    • 2018
  • Hypoptychus dybowskii, the Korean sandlance, is widespread in cold areas of the North Pacific. Although H. dybowskii has been considered to occur on the coast of Hamgyeongnam-do in Korea, the species is also distributed along the coast of Goseong-gun, Gangwon-do, south of Hamgyeongnam-do in the eastern part of the Korean Peninsula on the basis of newly collected specimens. In addition, many Koreans confuse H. dybowskii and Ammodytes japonicus (= A. personatus for Korean specimens) because the Korean common name or dialect of both species is "Yang-mi-ri", yet the two species differ in their external morphology. Hypoptychus dybowskii differs from A. japonicus in the location of the origin of the dorsal fin and the number of dorsal and anal fin rays.

다중수원 수처리 의사결정에 관한 실험적 연구 (An experimental study on decision making for multi-source water)

  • 정정우;조형락;이상호;채수권
    • 상하수도학회지
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    • 제29권1호
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    • pp.1-9
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    • 2015
  • A combined treatment system using multiple source water is becoming important as an alternative to conventional water supply for small-scale water systems. In this research, combined water treatment systems were investigated for simultaneous use of multi-source water including rainwater, ground water, river water, and reclaimed wastewater. A laboratory-scale system was developed to systematically compare various combinations of water treatment processes, including sand filtration, microfiltration (MF), granular activated carbon (GAC), and nanofiltration (NF). Results showed that the efficiency of combined water treatment systems was affected by the quality of feed waters. In addition, a simply approach based on the concept of linear combination was suggested to support a decision-making for the optimum water treatment systems with the consideration of final water quality.

동남권 잔골재수급 부족 문제를 해결할 대체골재 확보 가능성에 관한 연구 (A Study on the Possibility of Securing Alternative Aggregates to Solve the Problem of Supply and Demand of Fine Aggregate in Southeast Region)

  • 김하석;이도헌;김진만
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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    • pp.328-329
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    • 2018
  • The problem of imbalance between supply and demand of fine aggregates in the southeastern region due to the decrease in collection of EEZ(Exclusive Economic Zone) sea sand has been raised. In this paper, the possibility of securing alternative aggregate as a means to solve the problem of fine aggregate shortage in the southeast region was analyzed. As a result of the analysis, the alternative aggregate is easy to manufacture and its quality can be secured. And, it is suitable to use as an aggregate with less environmental burden. In addition, institutional improvement measures are needed for effective utilization and recycling of alternative aggregates.

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센서 링이 내식성과 기계적 특성에 관한 연구 (A Study on Ferrite Stainless Steel Corrosion Resistance or Mechanical Characteristics of 434LD2 ABS Sensor Ring)

  • 양현수;금영준;정풍기
    • 대한안전경영과학회지
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    • 제5권1호
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    • pp.129-141
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    • 2003
  • In this thesis, using the 400 series ferrite stainless steel such as 434LD$_2$ which are furter excellent then the existing ferric products in mechanical characteristics, and experiment has been conducted on corrosion resistance of sensor ring. The results are following. 1. The products before sintering are much more corrodible in the condition of spray test of salt water and ammonia than humidity and nitrogen condition. 2. 434LD$_2$ ferrite stainless steel has shown a good corrosion resistance without an addition surface treatment. thus the decreasing production process has been obtained. 3. As hardness value of $H_{RB}$ 80 and tensile test, 434LD$_2$ ferrite stainless steel with show a good endurance when it is combined to constant velocity joint (c/v joint), and has a good hardness properties endurable to sand and pebble impact.

Mobile-Immobile 모델을 활용한 유류오염토양 내 수리분산 특성 연구 (Analysis of Hydrodynamic Dispersion in Contaminated Soil based on Mobile-Immobile Model)

  • 김용성;우희수;박준범
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2008년도 추계 학술발표회
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    • pp.1512-1517
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    • 2008
  • Laboratory column tests were conducted in this study using $Cl^-$ tracers on Jumunjin sand to analyze contaminant transport in mixed contaminated soils. Results obtained from clean soils and soils containing residual diesel verified heterogeneous distribution of residual diesel, and clear acceleration of solute movement. In addition, asymmetric breakthrough curves indicated development of immobile region where solute movement becomes stagnant and creates tailing phenomenon.

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대형 sample을 이용한 해안 연약지반 압밀특성에 관한 연구 (Consolidation characteristics of soft ground using huge sample)

  • 홍성진;이문주;정두석;이우진
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2008년도 추계 학술발표회
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    • pp.1109-1114
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    • 2008
  • To investigate the effect of sample size on coefficient of consolidation of non-homogeneous soil, the result of a large size consolidation test using a huge undisturbed sample with $1200mm(D){\times}2000mm(H)$ in dimension is compared with that of oedometer test using undisturbed small sample. In addition, test results are compared with those of same test using remold sample. Experimental results show that, due to the lump of sand/silt was mixed in sample, the coefficient of consolidation of undisturbed samples have a difference for each tests. Whereas, the difference of coefficient of consolidation between remolded large and small samples is not found. Because sample size affects the test results, sample must be carefully selected for non-homogeneous soil.

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