• 제목/요약/키워드: Natural discharge

검색결과 387건 처리시간 0.026초

충적하천 실측자료의 저항계수와 관계식 (Resistance Factors and Relationships for Measurements in Fluvial Rivers)

  • 이종석
    • 한국콘텐츠학회논문지
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    • 제12권7호
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    • pp.445-452
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    • 2012
  • 본 연구는 충적하천에서 실측된 현장자료를 이용하여 흐름에 관한 저항계수와 관계식을 분석하고 유도하였으며, 연구에는 자연하천 자료 1,865개와 식생하천 자료 739개가 포함된 2,604개 자료가 사용되었다. 회귀분석에 의해 Manning 조도계수와 Darcy-Weisbach 마찰계수 관계식이 자연하천 하상재료와 식생하천 식생자료의 유량과 마찰경사를 함수로 하는 멱함수 형의 식으로 각각 유도되었다.

Vertical arrangement of coils for efficient cargo tank heating

  • Magazinovic, Gojko
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제11권2호
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    • pp.662-670
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    • 2019
  • Tanker cargo tanks are equipped with the means of raising and maintaining the cargo discharge temperature to a suitable level. In this paper, a new heating coil design is proposed and analyzed. Contrary to conventional designs, wherein the heating coils are evenly distributed over the tank bottom, the proposed design arranges the heating coils in the central part of the tank bottom, in a vertical direction. Due to the intensive cargo circulation generated, a forced convection is superimposed on a buoyancy-driven natural convection, providing a more efficient mixed convection heat transfer mechanism. Numerical simulations performed by using a finite volume method show that in the case of 7-bar steam Bunker C heavy fuel oil heating, a five-hour circulation phase average heat transfer coefficient equals 199.2 W/m2K. This result might be taken as an impetus for the more thorough experimental examination.

주거단지의 환경지속성 평가지표 개발을 위한 중요 평가항목 선정에 관한 연구 (Selectioni of the Important Evaluation Items for Development of Environmental Sustainability Indics of Housing Estate)

  • 박완규;안건영
    • 한국조경학회지
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    • 제26권3호
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    • pp.225-236
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    • 1998
  • The purpose of this study is to identify the important evaluatio items for developing the environmental sustainability indices of housing estate. In this research, the principles of environmental sustainability were established on the concept of ESSD, and twenty-two evaluation items were explored on the basis of questionnaire of experts, the twenty-two items are ranked in order of iportant level and it is a appeared that 'development density' is most iportant evaluation item. In conclusion, twelve important items were selectd; 'development density', 'preservation of natural forest and topography' , 'amount of green area', 'reduction of water pollution','reuse of wastes','garbage discharge','reduction of air pollution','distribution of land use','rainwater infiltraton and preservaton of underground water','site planning for energy saving','separated collection of wastes','access to natural forest andwaters around housing estate'

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스크롤 압축기의 공동 소음 규명을 위한 음향모드 분석 (Acoustic Mode Analysis to Identify Cavity Noise of Scroll Compressor)

  • 김승엽;이동수;서정환;허대녕
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 추계학술대회논문집
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    • pp.83-88
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    • 2004
  • Acoustic modes of internal region of 4-hp scroll compressor are identified by measuring transfer functions between a reference and 84 measuring points. The corresponding acoustic mode-shapes and natural frequencies were calculated by analysis software SYSNOISE. There exist two clearly distinguishable dipole modes of vertical and horizontal direction and a single quadrupole mode in the frequency region of interest. It shows that the natural frequencies of the identified modes are linearly sensitive to suction pressure (Ps) but relatively in sensitive to discharge pressure (Pd) in operating condition.

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치료중단행위에 대한 의료형법적 고찰 -의학적 충고에 반한 퇴원 사례를 중심으로- (A Study on Medical-criminal Problem of Withdrawing Life-Sustaining Treatment)

  • 조인호
    • 의료법학
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    • 제9권1호
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    • pp.319-382
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    • 2008
  • As a withdrawing care's study, the purpose of this study is searching about withdrawing care's acceptance and circumstances through Bora-mae hospital case(chapter 1). Withdrawing life-sustaining treatment has various forms. Though the meaning of euthanasia, death with dignity, natural death, physician assisted suicide are duplicated, the meaning of those are different slightly. Firstly, this study looks about the difference of the those meaning and acceptance range(condition) by withdrawing care's forms(chapter 2). Bora-mae hospital case sentenced guilty about physician who discharged incompetent patient who was after surgery by patient's wife determination. This Bora-mae case that sentenced guilty about discharge against medical advise(DAMA) that is regarded to custom has brought intensive confliction of legal, social, medical aspect, Bora-mae hospital case has many legal problems. First, as to criminal law rule 250(murder), the problem is whether discharge and withdrawing life-sustaining treatment is commission or omission. this study concluded omission(district court: omission, appeal, supreme court: commission). Because legal denounce point of discharge and medical treatment withdrawing is omission that physician who is obligatory on patient to cure. If physician's act is regarded omission, it is necessary to determine whether he has guardian status and obligation. Without guardian status and obligation, omission crime can't exist. This study decided that physician had guardian status and obligation and foundation of guardian status was pre-action or acceptance of emergency patient. Physician's medical treatment duty finished when patient(or patient's guardian) demands discharge. But when patient death is foreseen and other possible treatment does not exist, his duty of life prolonging treatment does not finish. This originate from physician's social responsibility and public status that limits patient's private liberty. This study regarded physician's action as accomplice about whether physician's discharging action is accomplice or the principal offender(district court: the principal offender, appeal, supreme court: accomplice). Though the principal offender needs criminal determination and action, there is no this common determination and functional action control of physician in Bora-mae case(chapter 3). Bora-mae hospital case partly originated from deficiency of legal, institutive system including medical security system shortage, the instruction is 1. medical security system strengthening, 2. hospital ethical committee's activity strengthening, 3. institutionalization of withdrawing life-sustaining treatment, 4. acceptance of pre-decision making system, 5. sufficient persuasion of physician for patient and faithful writing of medical paper, 6. respect for patients' self-determination and rights, 7. consciousness's changing for withdrawing life-sustaining treatment and persistent education about medical ethics(chapter 4). Considering Bora-mae case, medical sector is not the dead ground of a criminal punishment. Intervention of criminal law in medical sector give rise to ill effect, that is, excess medical examination and treatment, safeguard treatment, delay of discharge from a hospital. Because sufficient guarantee of life becomes mere empty slogan under situation that impose a burden of heavy cost to family or hospital, public and systematic solution should be given(chapter 5).

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전자부자 시스템을 활용한 자연하천의 유속과 유량 측정 (Measurement of Velocity and Discharge In Natural Streams with the Electronic Float System)

  • 이찬주;김원;김치영;김동구
    • 대한토목학회논문집
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    • 제29권4B호
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    • pp.329-337
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    • 2009
  • 본 연구에서는 GPS와 RF 통신을 이용하여 개발한 전자부자 시스템을 간략하게 설명하고 현장 실측 결과를 분석하고 제시 하였다. 개발된 시스템은 15개의 전자부자를 동시에 이용하여 유량측정에 활용할 수 있다. 전자부자는 GPS를 이용하여 실제 유하경로를 측정할 수 있으며, 이를 통해 기존 부자법에 비해 10% 정도의 유속 측정 정확도의 개선이 가능하였다. 또한 ADCP와 유속 측정값을 비교한 결과 대체로 일치하는 결과를 보였다. 전자부자와 일반 부자법에 의해 계산된 소단면별 단면적 차이는 -79~71%에 달하였으며, 특히 부자의 중앙 수렴 경향으로 인해 좌우안 부근의 단면적 차이가 증가하였다. 부자의 유하경로와 단면의 배치가 불규칙한 지점에서 전자부자는 댐 방류량 대비 5~6%의 유량 개선 효과를 가지는 것으로 나타났다. 전자부자는 GPS에 기반한 측위 정보를 제공함으로써 정확한 유속과 단면적 산정이 가능하며, 현장 여건과 관계없이 적은 인력으로 측정과 분석, 유량계산을 신속하게 실시간으로 수행함으로써 홍수 유량측정의 효율성을 높일 수 있을 것으로 기대된다.

연못을 이용한 동절기 인공습지 오수처리수의 추가 처리 (Pond System for Further Polishing of Constructed Wetland Effluent during Winter Season)

  • 윤춘경;전지홍;김민희;함종화
    • 한국농공학회지
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    • 제44권4호
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    • pp.139-148
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    • 2002
  • Pilot study was performed to examine the feasibility of the pond system for further polishing of treatment wetland effluent from December 2000 to June 2001. The wetland system used for the experiment was highly effective to treat the sewage during the growing season, but it was less effective and its effluent was still high to discharge to the receiving water body. Therefore, the wetland effluent may need further treatment to prevent water quality degradation. Pond system could be used to hold and further polish the wetland effluent during the winter season and ots feasibility was evaluated in this study. Additional water quality improvement was apparent in the pond system during winter season, and the pond effluent could be good enough to meet the effluent water quality standards if it is properly managed. Timing of the pond effluent discharge appears to be critical for pond system management because it is a closed system and whole water quality constituents are affected by physical, chemical, and biological pond environments. Once algae started to grow in mid-April, constituents in the pond water column interact each other actively and its control becomes more complicated. Therefore, upper layer of the pond water column which is clearer than the lower layer my need be discharged in March right after ice cover melted. In the experiment, water quality of the upper water column was markedly clear in March than ant other times probably because of freezing-thawing effect. The remaining lower water column could be further treated by natural purification as temperature goes up or diluted with better quality of wetland effluent for appropriate water uses. This study demonstrated the feasibility of pond system for subsequent management of wetland effluent during the winter season, however, more study is needed for field application.

다양한 연직배수재의 시험시공 및 초기현장 계측 (A Pilot Test of Various Vertical Drains and its Initial Monitoring Results)

  • 김주형;조삼덕
    • 한국지반신소재학회논문집
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    • 제5권2호
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    • pp.45-50
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    • 2006
  • 천연섬유배수재의 통수능은 플라스틱드레인보드(PDB)의 통수능에 비해 낮은 것으로 나타났지만, 모형시험 결과를 분석한 결과 기존 천연섬유배수재는 물론 새로 개발된 볏짚배수재도 플라스틱드레인보드 대체 가능성을 발견할 수 있었다. 본 연구에서는 천연섬유배수재의 현장 적용성을 검증하기 위해 천연섬유배수재를 이용한 현장시험시공을 수행하여 이들의 현장유효통수능을 확인하고자 하였다. 시험시공은 다수의 연직배수재와 수평배수재의 조합으로 이루어진 총 5지역으로 구성하였다. 현재까지 측정된 초기 계측자료를 이용한 각 배수재의 특성은 성토지연 등의 이유로 인해 정확히 파악할 수는 없었으나, 추후 성토완료 후의 결과를 분석한다면 여러가지 연직배수재 및 수평배수재 설치 지반의 압밀거동을 분석할 수 있을 것으로 판단된다.

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남해 강진만에서 성층 형성과 성층 파괴 과정 (Stratification and Destratification Processes in the Kangjin Bay, South Sea, Korea)

  • 정광영;노영재
    • 한국해양학회지:바다
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    • 제15권3호
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    • pp.97-109
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    • 2010
  • 하계 남강댐 방류수 유입에 의해 강하게 성층화된 남해 강진만에서 3차원 수치모델링 실험을 통해 태풍 통과시 염분장에 미치는 취송류의 영향과 성층 파괴에 대해 연구하였다. 조위와 유속장, 수온장, 염분장에 대해 각각 스킬 분석(skill analysis)을 이용하여 모델을 검증 하였고, 그 결과 대부분 90%가 넘는 재현율을 보였다. 모델은 조류, 담수유입에 의한 밀도류와 바람에 의한 취송류를 잘 재현했다. 대량 담수 유입이 있을 경우 바람의 영향은 강한 밀도류에 의해 상대적으로 큰 효과가 없으나, 담수유입이 감소하는 시기에는 바람이 수직 혼합작용을 촉진하여 바람을 부과하지 않은 모의 실험보다 2~3일 빠르게 성층을 파괴하였다. 담수 유입에 의한 성층과 바람에 의한 성층 파괴는 성층지수(Richardson 수(數), Ri)를 통하여 판단하였으며, 대량 방류시 성층지수는 급속도로 증가하여 Ri 수(數)가 7~20을 보였고, 방류가 중단된 이후에는 바람에 의한 혼합으로, 성층지수는 급격하게 감소하고 Ri 수(數)는 0~2까지 보였으며, 이 때 상하층간 염분은 일정하게 분포하였다.

공장창호의 환기특성에 관한 연구 (A Study on Ventilation Characteristics of Industrial Windows)

  • 박승욱;김태형;하현철;허영빈
    • 한국환경과학회지
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    • 제20권5호
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    • pp.581-587
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    • 2011
  • Industrial natural ventilation systems consist of gravity ventilator, the high/low windows and doors. Especially, the high windows play an important role in the industrial natural ventilation systems. Generally speaking, industrial high windows are divided into 3 types; louver type, $45^{\circ}$ open type and $90^{\circ}$ open type. This study was numerically and experimentally conducted. Three types of windows were tested to know the ventilation characteristics and estimate the ventilation efficiencies. Numerically, computational fluid dynamics software (AIR PAK Ver. 2.0) was used to observe the flow characteristics inside the industrial building and the concentration contours generated by the tracer gas method. Experimentally, the flow visualization technique and the tracer gas method were applied with the model building to characterize the flow pattern inside the model building and to estimate the ventilation efficiencies with the different windows. It was found that $90^{\circ}$ open type window was most effective for the discharge of pollutants from the industrial building. On the other hand, the louver type window was found to be less effective than any other windows.