• 한국안전학회지
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• 제21권2호
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• pp.70-79
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• 2006

many plumbing system are needed in the ceiling of the building as it becomes advanced more and more. This leads to make effective space between ceiling level and slab less. Also, piping system is not suitably arranged and operated if it is bent around the columns which they are a lot. But this system can be more effective if it passes through the columns directly. Most people think that those columns should not be damaged with such as holes. But actually this is existed in a hotel building in switzerland. This study is to fing out how much capacity the columns become damaged and low using model size of $20cm{\times}30cm$ rectangular section, and 160cm long, in the structural test. it's compressive strength is focused on $240kg/cm^{2}$ design strength, commonly used in korea. Compressive test for them was done at Hanyang University using UTM one thousand tone(1000t) capacity. Variable numbers for the study are one hole of dia 3cm with distance 20cm or 40cm, two holes of dia 3cm with 20cm and 40cm distance, one hole of dia 5cm with distance 20cm and 40cm, two holes of dia 5cm with 20cm and 40cm distance, me eccentric hole with 20cm and 40cm distance, Normal(without hole). two test specimens of each variable are made for the test. ED5H20 capacity was 16.7% decreased, compared to normal one. While ED5H40 distant 40cm from the end of column top showed 19.5% capacity decrease, compared to normal one. Strain of ED5H20 diameter 5cm, in distance of 20cm form the top of the column was less 5% than the one of diameter 3cm. Finally, conclusions are that in case of hole diameter 3cm, located at 20cm from the end of the column top, capacity was decreased down to 3, percent only compared to the same diameter hole with 20cm distant from the end of it.

• Geomechanics and Engineering
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• 제9권6호
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• pp.757-774
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• 2015

Reinforcing soils with the geosynthetics have been shown to be an effective method for improving the uplift capacity of granular soils. The pull-out resistance of the reinforcing elements is one of the most notable factors in increasing the uplift capacity. In this paper, a new reinforcing element including the elements (anchors) attached to the ordinary geogrid for increasing the pull-out resistance of the reinforcement, is used. Thus, the reinforcement consists of the geogrid and anchors with the cylindrical plastic elements attached to it, namely grid-anchors. A three-dimensional numerical study, employing the commercial finite difference software FLAC-3D, was performed to investigate the uplift capacity of the pipelines buried in sand reinforced with this system. The models were used to investigate the effect of the pipe diameter, burial depth, soil density, number of the reinforcement layers, width of the reinforcement layer, and the stiffness of geogrid and anchors on the uplift resistance of the sandy soils. The outcomes reveal that, due to a developed longer failure surface, inclusion of grid-anchor system in a soil deposit outstandingly increases the uplift capacity. Compared to the multilayer reinforcement, the single layer reinforcement was more effective in enhancing the uplift capacity. Moreover, the efficiency of the reinforcement layer inclusion for uplift resistance in loose sand is higher than dense sand. Besides, the efficiency of reinforcement layer inclusion for uplift resistance in lower embedment ratios is higher. In addition, by increasing the pipe diameter, the efficiency of the reinforcement layer inclusion will be lower. Results demonstrate that, for the pipes with an outer diameter of 50 mm, the grid-anchor system of reinforcing can increase the uplift capacity 2.18 times greater than that for an ordinary geogrid and 3.20 times greater than that for non-reinforced sand.

• 한국산학기술학회논문지
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• 제21권7호
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• pp.20-28
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• 2020

최근, 정부의 재생에너지 3020 정책에 따라 태양광전원 등의 신재생에너지전원을 확대하는 보급 사업이 적극적으로 시행되고 있다. 하지만, 대용량의 태양광전원이 배전계통에 연계되는 경우, 수용가전압이 규정전압 범위를 벗어나게 되는 현상이 발생될 수 있어, 태양광전원의 수용성이 저하되어 보급이 지연될 가능성이 있다. 따라서, 본 논문에서는 대용량의 태양광전원이 배전계통에 연계될 경우, 태양광전원의 수용성을 향상시키기 위하여, 선로전압조정장치(step voltage regulator, SVR)의 LDC(line drop compensation, LDC)방식에 의한 태양광전원의 수용성 향상 평가알고리즘을 제시한다. 또한, 배전계통 상용해석 프로그램인 PSCAD/EMTDC를 이용하여, LDC방식의 SVR과 대용량의 태양광 전원 등으로 구성된 복합 배전계통의 모델링을 제시한다. 이를 바탕으로, SVR의 운용방식에 따른 태양광전원의 수용성을 비교·분석한 결과, LDC방식으로 운용하는 경우에는 태양광전원이 6.5[MW]까지 연계되어도 수용가전압이 규정전압 범위 이내로 유지되어, 본 논문에서 제안한 LDC 방식에 의한 태양광전원의 수용성 향상 평가알고리즘의 유용성을 확인하였다.

• Journal of Biosystems Engineering
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• 제12권1호
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• pp.31-38
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• 1987

In order to improve the traditional post harvest system in Korea, a model for mechanized rice drying and storage system was developed and introduced as the first part of the study(Park, 1986). As the second part of the study, capital requirement and cost of the model system was analyzed. Also, optimum size of the model system was estimated by comparing with the traditional harvest system. From the study, the following results can be concluded: 1. The capital requirement of the model system decreases as the model size increases. For example, a model system having 500 ton storage capacity requires 439,000 Won/ton. However it requires 313,200 Won/ton only, if the model size increases to 1000 ton. 2. Also, total cost of the model system decreases as the model size increases. For example, total costs of the model system having 500 ton and 1000 ton storage capacity are 101,208 Won/ton and 69,320 Won/ton, respectively. 3. The breakeven point (optimum size) of the model can be estimated around 630 ton storage capacity if the operation rate is assumed as 100%. However, the optimum size of the model is 710 ton, if the operation rate it assumed 80%.

• 한국수소및신에너지학회논문집
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• 제7권1호
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• pp.19-28
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• 1996

Ti-Mn based hydrogen storage alloy were modified by substituting alloying elements such as Zr, V and Ni in order to design a high capacity MH electrode for Ni/MH rechargeable battery. When V was substituted in Ti-Mn binary system, the crystal structure was maintained as $Cl_4$ Laves phase at a composition of $Ti_{0.2}V_{0.4}Mn_{0.4}$ and $Ti_{0.4}V_{0.2}Mn_{0.4}$ and equilibrium pressure decreased below 1 atm without decreasing hydrogen storage capacity considerably. It was found that Ni should be included in Ti-V-Mn alloy in order to hydrogenate it electrochemically in KOH electrolyte. But substitution of Ni for Mn in Ti-V-Mn system caused the increase of equilibrium pressure above 1atm and decrease of hydrogen storage capacity. Zr was able to increase the reversible hydrogen storage capacity of Ti-V-Mn-Ni alloy without considerable change of hydrogenation properties. The electrochemical discharge capacity of Ti-Zr-V-Mn-Ni system were in the range of 350 - 464mAh/g and among them $Ti_{0.8}Zr_{0.2}V_{0.5}Mn_{0.5}Ni_{1.0}$ alloy had $Cl_4$ Laves single phase and very high electrochemical discharge capacity of 464mAh/g.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
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• pp.49-51
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• 2001

Recently, according to a rapid increase of the power demand, the KEPCO's 154kV lines are continuously expanded and become to the more complex loop system. As a result of increase of the fault capacity and the unbalance of power load flow, the circuit breaker have been exceeding the capacity limit of those in the loop power system. To solve this problem, APRS application will be necessary more and more.

• 산업경영시스템학회지
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• 제13권22호
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• pp.87-98
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• 1990

The performance analysis and capacity planning of Service Control Point which is real time response system is studied. The system is modeled by multiclass open queueing network. The analytical method is used to solve the queueing network. The solution of the model has product form solution. The focus of this paper is to investigate the capacity of system under the restriction of response time. To get the reasonable capacities, nonlinear programming problem is formulated and is solved by GINO. And the simulation model using SLAM II is formulated.

• 대한전기학회논문지
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• 제39권9호
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• pp.903-911
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• 1990

When load areas on a feeder are deenergized due to faults and scheduled outage, operators need to identify neighboring feeders, try to restore customers and minimize out-of-service areas. These cases include knowledge of system states and various constraints such as voltage drop. This paper concerns the load transfer in fault restoration and scheduled outage. Also, the operating constraints such as line current capacity, relay trip current, transformer capacity, voltage drop and line loss are considered. This expert system can propose the optimal load transfer method by analyzing the system state and considering the constraints.

• 한국지반환경공학회 논문집
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• 제4권4호
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• pp.85-96
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• 2003

연약지반 상부에 건설되는 구조물의 연약지반 보강에 사용되는 토목섬유의 하나인 지오셀은 평면형태의 지오그리드 보강재와는 다르게 3차원 형태로 제작된 토목섬유 단위 셀(Cell)안에 조립토를 채워 보강하는 시스템으로 종래의 지반보강을 위해 사용되는 지오그리드에서 한 단계 더 진전된 것으로서 삼차원 형태로 제작된 복합재를 이용하여 지반의 강도 및 지지력을 증가시키는 방법이다. 본 논문에서는 지반의 지지력을 증가시킬 수 있는 지오셀 시스템에 대한 지지력 메카니즘을 분석하기 위하여 모형토조를 이용한 평판재하시험을 실시하였고 본 실험을 통하여 지오셀 보강 유 무, 층수와 지오셀 형상에 따라 얕은 기초의 지지력과 연직변위에 미치는 영향을 분석였다.

• 대한안전경영과학회지
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• 제11권1호
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• pp.15-26
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• 2009

This research has so far found out problems including the second damage of extinguishant and the short time of emission when using the existing dry chemical extinguisher and gas type extinguisher, and impossibility of constant extinguishing due to the inability of recharge at the field. To solve such problems, a mobile water mist system was developed and used. However, it is judged that more improved mobile water mist system is necessary because the force of the fire changed diversely and remote villages in mountains or islands where the force of fire extinguishing is short or delayed, require high capacity of fire extinguishing. Therefore a new equipment was developed and tested focusing on the improvement of extinguishing capacity and the performance of extinguishing was found out to be improved, compared to the existing mobile water mist system. It also showed a superior extinguishing capacity to dry chemical extinguisher or gas type extinguisher. Afterward an additional research is required of simplification of equipment, price cutting and the development of additive to enable high performance even with just small extinguishant.