• 제목/요약/키워드: bed

검색결과 6,919건 처리시간 0.037초

파랑작용에 의한 준설토 지반의 안정성에 관한 실험적 연구 (Experimental Study on the Stability of Dredged Soil Bed under Cyclic Wave Actions)

  • 강윤구
    • 한국해양공학회지
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    • 제20권4호
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    • pp.43-49
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    • 2006
  • Detailed investigations were carried out on the stability of the dredged soil bed against wave actions, aimedat establishing the design method of artificial tidal flats using dredged soil. The soil was dredged at Nagoya port, Japan, and has a mean grain size of 0.013mm. Basic features of artificial dredged soil bed against wave actions were explained from a series of model experiments in a wave flume. The two types of section shapes were employed; one is a horizontal bed and the other is a sloped one. Changes of the bed profile, shear strength, grain size distribution and water content, according to the wave actions, were measured in detail. The cumulative effect of the wave actions, over about one week, was investigated. A dredged soil bed moves withthe wave actions with relatively small wave height. It should be especially. noted that the clay component is dissolved and flown out, away from the surface layer, and consequently the surface layer hardens, as if it is covered with sand. Wren the wave height is gradually increased, the bed is not liquefied and the shear strength of the dredged bed is increased by a wave-induced dissipation of pore pressures in the bed and a decrease of clay component by the wave-induced leakage.

SEWGS 시스템을 위한 WGS 촉매의 반응성에 미치는 수소 전 처리 방법의 영향 (Effect of Pre-treatment Method on Reactivity of WGS Catalyst for SEWGS System)

  • 류호정;박지혜;이동호;선도원;이영우
    • 한국수소및신에너지학회논문집
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    • 제25권4호
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    • pp.355-363
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    • 2014
  • Thermal shock or overheating of WGS catalyst for SEWGS system during hydrogen pre-treatment can cause reactivity decay of the catalyst. To select appropriate pre-treatment condition, temperature profiles of catalyst bed (or outside fluidized particle bed of bed insert) during pre-treatment were measured and then CO conversions of those catalysts during WGS reaction were also measured and compared. Drastic overheating of catalyst took place when we reduce catalyst at fixed bed condition and these catalysts showed low CO conversion during WGS reaction. On the contrary, there was no overheating of catalyst at fluidized bed condition not only physical mixing case but also bed insert case. Spring type bed insert showed acceptable CO conversion even at low WGS content. Consequently, feasibility of high CO conversion without decay of reactivity of catalyst and holding the WGS catalyst inside the SEWGS reactor as tablet shape were confirmed using spring type bed insert.

HEC-6 모형을 이용한 유사량 공식에 따른 하상변동 민감도 분석 - 낙동강 하류를 대상으로 (Sensitivity Analysis of Bed Changes for Different Sediment Transport Formulas Using the HEC-6 Model - The Lower Nakdong River)

  • 정원준;지운;여운광
    • 한국환경과학회지
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    • 제19권10호
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    • pp.1219-1227
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    • 2010
  • In this study, the sensitivity analysis of bed changes due to the various sediment transport equations have been conducted for 80 km reach of the Lower Nakdong River using the HEC-6 which is one dimensional numerical model. The bed elevation changes according to the different sediment transport formulas were compared and analyzed quantitatively. As a result of the numerical simulation, the final bed elevation calculated by Engelund and Hansen(1967), Ackers and White(1973), and Yang(1979) formulas was similar to one another in configuration. The bed change simulated by Engelund and Hansen(1967) were greatest among them, for example, 5.5 m deposition and 2.9 m erosion for 100 years. Also, in the case of Toffaleti (1969) equation, the maximum bed deposition of 8.04 m after 100 years was induced at the 73 km location upstream of the Nakdong River Estuary Barrage. Meyer-Peter-M$\ddot{u}$ller(1948) and Wilcock(2001) formulas produced the deposition only at the upstream end and there was little bed change in the downstream area. The unreal bed configuration of continuously up and down pattern was simulated by Laursen(1958) transport equation.

와상환자복 하의 디자인 개발 (A Design Development of Hospitalized Patients' Pants for Bed-ridden Patients)

  • 박혜원;류은정
    • 한국의류학회지
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    • 제32권9호
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    • pp.1418-1426
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    • 2008
  • This study aims to develop the functional pants for the hospitalized bed-ridden patient. The procedure of this study consisted of three parts. First, the interview survey of nursing care givers was conducted to inquire into the conditions of bed-ridden patients' clothing. Second, the bed-ridden patients' pants design and sample making were accompanied. Then, the wearing tests and design development were completed. The results are as follows; The conditions of bed-ridden patients' clothing were the convenience of clothing change, the partial opening for diaper change and medical treatment and the ventilation for bedsore prevention. The design development of the bed ridden patients' pants was accomplished which had the side seams with two way opening zippers, the wraparound pattern of abdomen and the opening under crotch applied the advantage of korean traditional underwear sokkot. The samples' wearing tests were performed three times and those subjects were the hospitalized bed-ridden patients. Consequently, we suggested the appropriate hospitalized patients' pants for bed-ridden patient.

중환자실 병상주변공간의 면적과 간격에 관한 연구 (A Study on the Area and Clearances around Patient Bed Space in Intensive Care Unit)

  • 이현진;권순정
    • 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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    • 제25권3호
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    • pp.47-55
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    • 2019
  • Purpose: This study tries to propose the dimensions and area related to patient bed and surroundings in ICU considering nurses' observation and medical care. Methods: Literature survey, 11 Case studies, some Interviews with nurses and measuring of medical equipments' dimension in ICU have been mobilized in order to deepen the ICU bed area standards. Results: 0.3m clearance between head wall and patient bed is necessary for emergency cases. The minimum distance at the foot of the bed should not be less than 0.9m for EMR cart and medical tray. The clear floor area of one bed and surroundings in open ward is $10.2m^2(3m{\times}3.4m)$. In a single-bed patient room, the minimum clear floor area is $16.0m^2(4m{\times}4m)$. Considering the control of cross infection in ICU, Single bed patient room is recommended. Implications: The result of this study can be applied to the design of ICU and legislation of ICU standard.

L자형 이동상수로에서 댐 붕괴파의 수치해석 (Numerical Analysis of Dam-break Waves in an L-shaped Channel with a Movable Bed)

  • 김대근;황건
    • 한국수자원학회논문집
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    • 제45권3호
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    • pp.291-300
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    • 2012
  • 댐 붕괴 직후에 댐 붕괴 근역에서의 댐 붕괴파 및 댐 붕괴파로 인한 하상변동을 추적하기 위하여 RANS를 지배방정식으로 하는 FLOW-3D를 이용한 3차원 수치모의를 수행하였다. 특히 이동상에서의 하상변동과 그 하상변동으로 인한 홍수파의 변동을 고정상에서의 해석결과와 비교하였다. 그 해석 결과를 정리하면 다음과 같다. 첫째, L자형 실험수로에서의 홍수파 해석 및 이동상 실험수로에서의 홍수파와 하상변동 해석 결과는 해당 수리실험을 만족스럽게 재현하고 있다. 둘째, 부유사의 농도는 홍수파의 전면에서 가장 높은 값을 보이며, 하상침식은 흐름이 급변하는 댐 직하류 지점에서 가장 크게 발생한다. 수로의 상류에서 발생하는 부유사로 인해 하류에서는 침식과 퇴적이 번갈아서 발생한다. 홍수파가 도달하는 초기에는 L자형 만곡부의 내측에서 침식이 우세하게 발생하나, 시간이 지나며 침식은 점차 만곡부의 외측으로 이동하는 양상을 보인다. 셋째, L자형 이동상에서의 홍수파는 하상의 침식 및 퇴적으로 인해 고정상에서의 홍수파에 비해 그 전파가 지체되며 홍수위가 크게 상승한다.

섬진강 하류의 하상변동 특성 분석 및 예측 (The Prediction and Analysis of Bed Changes Characteristics in the Seomjin River Downstream)

  • 전일권;김민환
    • 한국방재학회 논문집
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    • 제9권1호
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    • pp.115-121
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    • 2009
  • 섬진강 하류의 하상변동 특성 분석 및 하상변동을 예측함으로서, 하도 및 유역관리에 효과적으로 이용하도록 하였다. 하상변동 특성 분석에 필요한 자료(단면, 하상구성물질, 기점수위, 조도계수 등)는 섬진강하천정비기본계획에서 실측 및 분석한 것을 활용하였다. 또한 하상변동 예측은 HEC-6 모형으로 수행하였다. 본 연구의 주요 연구 결과를 요약하면 다음과 같다. 섬진강 하류 하상변동의 주요인은 수문인자의 변화에 따른 것이라기보다는 과도한 하상골재 채취 때문으로 판단된다. 마찰속도와 대표 입경의 관계와 무차원소류력과 대표입경의 관계를 토대로 하도안정성을 정성적으로 분석한 결과 섬진강 하류 하상은 대부분의 구간에서 상승하는 경향을 나타내고 있다. 섬진강 하도의 대부분의 지점에서 2003년의 하상구성물질은 1989년에 비해 자갈의 구성비가 높아지고 모래의 구성비가 작아졌다. 하상변동을 예측한 결과 섬진강 하류의 하상은 하구에서 약 9 km 지점까지 1.5 m 내외로 상승하고, $9{\sim}21\;km$ 구간은 1 m 내외로 상승과 저하가 반복되며, $22{\sim}25\;km$ 구간은 0.5 m 내외로 하강할 것으로 예상된다. 이러한 결과로 볼 때 섬진강 하류 구간의 하상은 대체로 점점 상승할 것으로 판단된다. 다만, 본 연구의 하상변동 예측은 인위적인 골재채취가 없다는 가정 하에 수행된 것이므로, 과거와 같이 하상에서 대규모 골재채취가 진행되면 본 연구의 예측 결과와는 상이하게 하상이 저하되는 결과를 초래할 것이다.

모암(母岩)의 전기비저항(電氣比抵抗) 변화(變化)에 따른 외견비저항(外見比抵抗)의 변화양상(變化樣相)에 관(關)한 모형연구(模型硏究) (A Model Study on the Variation of Apparent Resistivity along with Electric Resistivity Change of Host Rock)

  • 민경덕;전명순
    • 자원환경지질
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    • 제13권3호
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    • pp.159-166
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    • 1980
  • A model study was conducted for the investigation of apparent resistivity variation along with electric resistivity variation of host rock and dip variation of bed. Experiments were carried out for the cases of horizontal and dipping beds in a water tank by using Wenner and Schlumberger arrays and by changing salinity of water. The ratios of resistivity values of the bed to that of brine were 1 : 10, 1 : 50, 1 : 100 and 1 : 500. Natural coally-shale of $55cm{\times}35cm{\times}3.5cm$ was used as a bed for experimental model, and brine as a host rock. Equi-resistivity curves and characteristic curves were obtained for each case of the experiment. The equi-resistivity curve was drawn both on the cross section parallel to strike of bed and longitudinal section perpendicular to it. The characteristic curve was drawn on the cross section. In the case of dipping bed of different dips, the curves are parallel to the boundary of the bed in the upper part of the bed, and are inclined to the opposite direction with the same angle of the dip of bed in the lower part. We can deduce, from the equi-resistivity curves, the location, shape and dip of the bed. It is shown in the characteristic curves that when the ratio of resistivity value of bed to that of host rock increases, the slope of curves becomes steeper, location of low-resistivity zone lower, and the width of it narrower. The slope of curves also becomes steeper when dip of bed increases. We can deduce, from the characteristic curves, the ratio of resistivity values between adjacent beds. It was found out from the experiments that electric resistivity method could be applicable to prospecting for underground geology with an electric resistivity contrast of 1 : 10. This fact strongly suggests that distinction of coal from coally-shale could be possible in a certain field condition.

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Tumor bed volumetric changes during breast irradiation for the patients with breast cancer

  • Chung, Mi Joo;Suh, Young Jin;Lee, Hyo Chun;Kang, Dae Gyu;Kim, Eun Joong;Kim, Sung Hwan;Lee, Jong Hoon
    • Radiation Oncology Journal
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    • 제31권4호
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    • pp.228-233
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    • 2013
  • Purpose: The aim of this study was to evaluate changes in breast tumor bed volume during whole breast irradiation (WBI). Materials and Methods: From September 2011 to November 2012, thirty patients who underwent breast-conserving surgery (BCS) followed by WBI using computed tomography (CT) simulation were enrolled. Simulation CT scans were performed before WBI (CT1) and five weeks after the breast irradiation (CT2). The tumor bed was contoured based on surgical clips, seroma, and postoperative change. We retrospectively analyzed the factors associated with tumor bed volumetric change. Results: The median tumor bed volume on CT1 and CT2 was 29.72 and 28.6 mL, respectively. The tumor bed volume increased in 9 of 30 patients (30%) and decreased in 21 of 30 patients (70%). The median percent change in tumor bed volume between initial and boost CT was -5%. Seroma status (p = 0.010) was a significant factor in tumor bed volume reduction of 5% or greater. However, patient age, body mass index, palpability, T stage, axillary lymph node dissection, and tumor location were not significant factors for tumor bed volumetric change. Conclusion: In this study, volumetric change of tumor bed cavity was frequent. Patients with seroma after BCS had a significant volume reduction of 5% or greater in tumor bed during breast irradiation. Thus, resimulation using CT is indicated for exquisite boost treatment in breast cancer patients with seroma after surgery.

축산폐수의 혐기성 충전층과 유동층 생물막법에 의한 처리효율의 비교연구 (A Comparative Study on Treatment Efficiencies by Anaerobic Packed and Fluidized-bed Biofilm of Livestock Wastewater)

  • 김은호;박현건;장성호
    • 한국환경보건학회지
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    • 제24권1호
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    • pp.54-61
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    • 1998
  • This study was conducted in order to evaluate the treatment efficiencies of anaerobic packed and fluidized-bed biofilm and to investigate applicability in treating livestock wastewater. Biocarbonate alkalinity(BA) and volatile fatty acid(VFA) were about 3,230-3,270 mg/l, 3,790-3,126 mg/l(as CaCO$_3$) and 224-402 mg/l, 141-387 mg/l(as CH$_3$COOH), and VFA/BA ratio was about 0.069~0.12, 0.045-0.12 in packed and fluidized-bed biofilm. When COD loading rate was 6.0 kg COD/$m^3\cdot$ day in packed and fluidized-bed biofilm, methane gas production were 3.23 l/day and 4.38 l/day, respectively. In the same COD loading rate, methane gas production volumes per kg COD removal were 0.25 m$^3$ CH$_4$/kg COD$_{rm}$ and $0.28 m^3 CH_4/kg COD^{rm}$, respectively. At this time, it could be estimated that fluidized-bed biofilm was more high. In case of HRT 0.94 day(6.0 kg COD/$m^3\cdot$ day) and 11 day(0.5 kg COD/$m^3\cdot$ day), packed-bed biofilm showed 59% and 81% COD removal efficiency, respectively. While fluidized-bed biofilm showed 72% and 85% removal efficiency, respectively. It was showed that fluidized-bed biofilm was more efficient. Packed-bed biofilm was higher than fluidized in treatment efficiencies of organic matters, but required continuous treatment using combined system, because it was very exceeded over an environmental standard solidified from '96 year. In operating fluidized-bed biofilm, if farm house consider high power cost according to high circulation ratio in an economic point of view, it would have an effect that farm house use packed-bed biofilm as combined system in treating livestock wastewater.

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