• 해양환경안전학회지
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• 제25권5호
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• pp.519-526
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• 2019

본 연구는 대기정박지의 신설 및 조정이 필요한 항만을 위해 정박지의 적정 용량을 산정하기 위한 방법론을 제시하고, 이를 진해만 내 항만과 부산에 적용하여 국내 주요 항만의 정박지 용량과 비교 분석하여 적용에 무리가 없는지 검토하기 위한 목적이 있다. 이를 위해 항만을 이용하는 선박의 총톤수 용량과 동시 정박 가능 용량의 개념을 정의하고 정박지 용량지수를 계산하여 대상항만을 위한 적정 정박지 용량을 산정하는데 이용하였다. 그 결과 진해만 내 항만의 정박지 용량지수는 0.89로 산출되었으며, 대기정박지 신설을 위한 적정 정박지 용량지수는 6.0 수준으로 분석되었다. 본 연구에서 제시한 정박지 용량지수의 개념을 정박지 설계 기준으로 반영할 경우 정박지를 이용하는 선박의 안전, 정박지 안전성 및 항만의 효율적인 운영에 도움을 줄 수 있을 것으로 판단된다.

• 한국지리정보학회지
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• 제14권1호
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• pp.94-106
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• 2011

본 연구에서는 GIS 기반 토사유실모델과 유사전달률 그리고 유효저수용량을 고려하여 댐 저수지별 흙탕물 발생 가능성을 분석하였다. 이를 위해 DEM, 토양도, 토지피복도 등의 공간자료를 기반으로 RUSLE 모델의 입력인자를 평가하여 유역대책 수립시 필요한 각 유역별 취약인자를 분석하였으며, 고랭지밭 특성을 고려한 토사유실량 평가를 통해 강우시 유역내 토사발생 잠재성을 분석하였다. 또한 유역면적을 고려한 유사전달률을 통해 유역별 토사유출량을 계산한 결과 충주댐과 소양강댐이 가장 높은 값을 나타내었으며, 유효저수용량을 고려한 유사농도 분석결과에서는 임하댐과 충주댐이 각각 0.791 $kg/m^3/yr$와 0.526 $kg/m^3/yr$로 가장 높게 나타났다. 특히 임하댐의 토사유출량은 소양강댐유역에 비해 약 2.36배 낮게 나타났으나 임하댐 저수지의 유효저수용량이 소양강댐에 비해 약 4.48배 작아 유사농도는 오히려 임하댐 저수지가 1.90배 높게 분석되었다. 본 연구에서는 10년 평균 강우사상을 이용하여 유사농도를 계산하였으며, 이를 통해 각 유역별 토양, 지형, 식생, 경작상태 그리고 유효저수용량 측면을 검토할 수 있었다. 따라서 이러한 정량화된 유사농도 자료들은 저수지의 고탁수 발생 잠재성을 평가할 수 있고 저수지 관리를 위한 효과적인 도구로도 활용될 수 있으리라 판단된다.

• 한국지반공학회논문집
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• 제36권11호
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• pp.35-49
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• 2020

마이크로파일의 수평 지지력은 파일의 본 수, 설치 각도와 간격 등 설치조건에 좌우된다. 마이크로파일에 관한 기존 연구는 연직 지지특성에 대한 평가와 효과적인 설치방법의 제안 등에 국한되어 있고, 파괴 모드와 같은 파괴 메커니즘 등에 대한 연구는 거의 없는 실정이다. 또한 대부분의 수평 지지력에 관한 연구도 단열 마이크로파일(1-row micropile)에 관한 것이다. 이에 본 연구에서는 파일의 설치 길이, 각도, 간격 등 설치조건을 달리한 경우 복열 마이크로 파일(2-row micropile)의 거동 및 지지특성을 평가하기 위하여 모형시험을 수행하였다. 모형시험결과, 설치 각도 θ > 0°인 경우(비교차 설치)의 복열 마이크로파일의 수평 지지력은 파일의 간격에 좌우되며, 설치 각도 θ = +30°인 조건이 지지력 증대에 가장 효과적이었다. 또한 설치 각도 θ < 0°인 경우(교차 설치)에는 파일의 간격과 각도에 좌우되며, 설치 각도 θ = -15°인 조건이 지지력 증대에 가장 효과적인 것으로 나타났다.

• Structural Engineering and Mechanics
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• 제48권4호
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• pp.479-500
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• 2013

This paper presents the experimental as well as analytical study conducted on layer-bonded scrap tire rubber pad (STRP) isolators to develop low-cost seismic isolators applicable to structures in developing countries. The STRP specimen samples were produced by stacking the STRP layers one on top of another with the application of adhesive. In unbonded application, the STRP bearings were placed between the substructure and superstructure without fastening between the contact surfaces which allows roll-off of the contact supports. The vertical compression and horizontal shear tests were conducted with varying axial loads. These results were used to compute the different mechanical properties of the STRP isolators including vertical stiffness, horizontal effective stiffness, average horizontal stiffness and effective damping ratios. The load-displacement relationships of STRP isolators obtained by experimental and finite element analysis results were found to be in close agreement. The tested STRP samples show energy dissipation capacity considerably greater than the natural rubber bearings. The layer-bonded STRP isolators serve positive incremental force resisting capacity up to the shear strain level of 150%.

• 대한임상전기생리학회지
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• 제1권1호
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• pp.87-100
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• 2003

The present studies have been designed to evaluate the effect of acute wound healing that frequency and intensity of pulsed ultrasound application in diabetic rat. Mild diabetes mellitus was induced in rat with 45 mg/kg streptozotocin. The results were analyzed and summarized as follows: 1. The rate of wound length on ultrasonic capacity in $1.0\;W/cm^2$ $SATA_i$ group was more significantly decreased than $0.5\;W/cm^2$ $SATA_i$ group. 2. In the histological change, the $1.0\;W/cm^2$ $SATA_i$ application group was more effective than $0.5\;W/cm^2$ $SATA_i$ group, decrease of inflammatory cell was significantly in several groups. From the conclusions above, in this study application of 3 MHz pulsed ultrasound in acute wound healing, $1.0\;W/cm^2$ $SATA_i$ capacity can be an effective way of promotion wound healing than $0.5\;W/cm^2$ $SATA_i$ capacity in diabetic rat.

• 대한기계학회논문집B
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• 제24권9호
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• pp.1277-1284
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• 2000

To enhance heat transfer characteristics of water, micro-encapsulated octadecane of about $10{\mu}m$ diameter was added to water. Viscosity of the slurry was measured by using a capillary tube viscometer. The measured viscosity decreased as the temperature of the slurry increased, and it increased as the fraction of the capsules in the slurry increased. Thermal characteristics of the octadecane were studied by using a differential scanning calorimeter. The melting temperature and the melting energy of the octadecane were found to be $28.6^{\circ}$ and 34.4kcal/kg, respectively. The convective heat transfer characteristics of the slurry were investigated in a flow loop with a constant heat flux test section. Friction factor of the slurry flow was found to be similar to the expected curve by Petukhov. The Nusselt number of the slurry flow was highest when the octadecane melted. Effective thermal capacity of the 14.2% slurry was found to have 1.67 times of the thermal capacity of water.

• 한국환경과학회지
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• 제22권9호
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• pp.1131-1139
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• 2013

Desorption characteristics of VOCs were investigated for the effective recovery of gasoline vapor. The adsorption capacity and desorption capacity were excellent at relatively low temperatures. The differences in the desorption capacity were not large in the condition; desorption temperature $25^{\circ}C$, desorption pressure 760 mmHg, inlet air flow rate 0.5 L/min, but were relatively great in the condition; desorption temperature $0^{\circ}C$, desorption pressure 60 mmHg, inlet air flow rate 1.0 L/min. The desorption ability of pentane was increased to about 81.4%, and the desorption ability of hexane was increased to about 102%, also the desorption ability of toluene was increased to about 156.7% by changes of temperature, pressure, inlet air flow rate in the experimental conditions. The optimum desorption condition for the effective recovery of VOCs was in the conditions; desorption temperature $0^{\circ}C$, desorption pressure 60 mmHg, inlet air flow rate 1.0 L/min.

• International Journal of Concrete Structures and Materials
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• 제6권1호
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• pp.19-29
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• 2012

In this study, three isolated interior flat slab-column connections that include three types of shear reinforcement details; stirrup, shear stud and shear band were tested under reversed cyclic lateral loading to observe the capacity of slab-column connections. These reinforced joints are 2/3 scale miniatures designed to have identical punching capacities. These experiments showed that the flexural failure mode appears in most specimens while the maximum unbalanced moment and energy absorbing capacity increases effectively, with the exception of an unreinforced standard specimen. Finally, the results of the experiments, as wel l as those of experiments previously carried out by researchers, are applied to the eccentricity shear stress model presented in ACI 318-08. The failure mode is therefore defined in this study by considering the upper limits for punching shear and unbalanced moment. In addition, an intensity factor is proposed for effective widths of slabs that carry an unbalanced moment delivered by bending.

• Journal of Biosystems Engineering
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• 제30권3호
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• pp.141-146
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• 2005

Worldwide consumption of vegetable soybean has been increasing recently, but, in the process of vegetable soybean production threshing and seperation work accounts for about $80\%$ of overall labor. Therefore, developing of the vegetable soybean thresher is necessary to reduce the cost of labor. The main objective of this study is to develop the vegetable soybean thresher which is suitable for domestic circumstances. The threshing and separating performance, operating cost, and field capacity of developed vegetable soybean thresher are investigated and analysed. The results are as follows. The effective field capacity of the developed vegetable soybean thresher was shown as 4.8hr/10a, and reduced as much as 11.7 times compared with human labor. The ratio of unthreshed soybean-pod to stem after threshing work was shown as $1.5\%$ and the damaged pod ratio of detached soybean was shown as $1.8\%$. The cost of human labor was shown as 2,560,000 won/ha, but the operating of the developed vegetable soybean thresher was shown as 503,000won/ha. If the vegetable soybean thresher would be used in our farm, the minimum cultivation area appeard to be 22.7a for the cost effective management.

• Structural Engineering and Mechanics
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• 제54권6호
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• pp.1245-1266
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• 2015

In this research, the cylindrical absorber made of expanded metal sheets under impact loading has been examined. Expanded metal sheets due to their low weight, effective collapse mechanism has a high energy absorption capacity. Two types of absorbers with different cells angle were examined. First, the absorber with cell angle ${\alpha}=0$ and then the absorber with angle cell ${\alpha}=90$. Experimental Study is done by drop Hammer device and numerical investigation is done by finite element of ABAQUS software. The output of device is acceleration-time Diagram which is shown by Accelerometer that is located on the picky mass. Also the output of ABAQUS software is shown by force-displacement diagram. In this research, the numerical and experimental study of the collapse type, force-displacement diagrams and effective parameters has been investigated. Similarly, the comparison between numerical and experimental results has been observed that these results are matched well with each other. From the obtained results it was observed that the absorber with cell angle ${\alpha}=0$, have symmetric collapse and had high energy absorption capacity but the absorber with cell angle ${\alpha}=90$, had global buckling and the energy absorption value was not suitable.