• 제목/요약/키워드: Preliminary Feasibility

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Gas Turbine Engine Based Hybrid Propulsion System Modeling and Simulation (가스터빈엔진 기반 하이브리드 추진시스템 모델링 및 시뮬레이션)

  • Lee, Bohwa;Kim, Chuntaek;Jun, Sangook;Huh, Jae-Sung;Kim, Jae-Hwan
    • Journal of the Korean Society of Propulsion Engineers
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    • v.26 no.3
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    • pp.1-9
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    • 2022
  • The aircraft targeted in this study is a vertical take-off and landing aircraft with 4 to 5 passengers, and the propulsion system for the aircraft is a distributed hybrid propulsion system that uses a gas turbine engine and a battery pack as the main power source to supply the power required by multiple motors. In this study, a design/analysis platform for a hybrid propulsion system was developed using the MATLAB/Simulink program based on the preliminary design results. Through simulation analysis, the output characteristics and operating range of each power source according to the mission profile were confirmed, and through this, the feasibility of the preliminary design result was confirmed.

Core design study of the Wielenga Innovation Static Salt Reactor (WISSR)

  • T. Wielenga;W.S. Yang;I. Khaleb
    • Nuclear Engineering and Technology
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    • v.56 no.3
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    • pp.922-932
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    • 2024
  • This paper presents the design features and preliminary design analysis results of the Wielenga Innovation Static Salt Reactor (WISSR). The WISSR incorporates features that make it both flexible and inherently safe. It is based on innovative technology that controls a nuclear reactor by moving molten salt fuel into or out of the core. The reactor is a low-pressure, fast spectrum transuranic (TRU) burner reactor. Inherent shutdown is achieved by a large negative reactivity feedback of the liquid fuel and by the expansion of fuel out of the core. The core is made of concentric, thin annular fuel chambers containing molten fuel salt. A molten salt coolant passes between the concentric fuel chambers to cool the core. The core has both fixed and variable volume fuel chambers. Pressure, applied by helium gas to fuel reservoirs below the core, pushes fuel out of a reservoir and up into a set of variable volume chambers. A control system monitors the density and temperature of the fuel throughout the core. Using NaCl-(TRU,U)Cl3 fuel and NaCl-KCl-MgCl2 coolant, a road-transportable compact WISSR core design was developed at a power level of 1250 MWt. Preliminary neutronics and thermal-hydraulics analyses demonstrate the technical feasibility of WISSR.

Regulation Issues in Korea and Technical Feasibility Evaluation of 3D Printing-Based Medical Device Repair (3D 프린팅 기술의 의료기기 수리 적용에 대한 국내 규제 이슈 및 기술적 적합성 평가)

  • Yun, Sung Uk;Nam, Kyoung Won
    • Journal of Biomedical Engineering Research
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    • v.41 no.2
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    • pp.75-83
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    • 2020
  • In large-scale hospitals, the department of biomedical engineering should always provide quick repair service for damaged medical devices to guarantee continuous patient treatment. However, in actual circumstances, there are so many time-consuming issues that delays device repair for weeks or even months; therefore, it is required to prepare alternative ways for quick repair service. In this study, we first mentioned about the regulation issues in Korea about the 3D printing-based medical device repair, and then introduced the results of our preliminary study that evaluated the feasibility of 3D printing-based medical device repair before real-field application. Results of the study demonstrated that, in all of the 23 cases, parts for repair that were manufactured by 3D-printing were successfully fixed and connected to the main body of the original device, and showed sufficient rigidity for protecting internal parts of the device. Considering the experimental results, medical device repair by applying 3D printing technology can be a promising alternative in cases when regular repair process is not available or takes too much time.

Preliminary Evaluation of a Proposed Marine Ranching Project in Korea (우리 나라 바다목장화 사업의 예비적 경제성 평가)

  • 표희동
    • The Journal of Fisheries Business Administration
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    • v.29 no.2
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    • pp.199-216
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    • 1998
  • An economic appraisal of a proposed marine ranching project is analysed using capital budgeting model such as net present value(NPV) and internal rate of return( IRR) as well as sensitivity analysis and goal seeking model. Of the factors for economic appraisal, direct benefits are to be determined by estimated harvest, prices and costs incurred by catching fishes, and indirect benefits include the additional economic effect of recreational fishing. And judging the worth of these project options depends upon the choice of discount rate of which 8.5% is recommended here. On the basis of estimated production, prices and costs the project is expected to yield NPV=615 million won and IRR=8.8%, which is quite accepted for an economic feasibility, under the first scenario, and NPV= -127 million won and IRR=7.93%, which is rejected, under the second scenario. Sensitivity analysis has been performed by calculating the switching value and sensitivity indicator in respect of the main project parameters. The results suggest that the project NPV and IRR are especially sensitive to fishes(rock fish and other rock fish) prices and fixed costs. Finally goal seeking analysis is carried out in order to reach a desired level of performance like NPV=0 in respect of the amount of hatchery-reared juverniles, the prices and the discount rate.

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Feasibility Study on the Construction of Small Hydro-Power Plants in Gumi Sewage Treatment Plant Discharge Point (구미하수처리장 방류구에서의 소수력발전 설치 및 운영에 관한 연구)

  • Nah, Dong-Hun;Lee, Seung-Hwan
    • Journal of Korean Society of Water and Wastewater
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    • v.24 no.2
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    • pp.173-181
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    • 2010
  • This study was conducted to investigate the possible installation of small hydro-power plant at the discharge point of Gumi sewage treatment plant (STP) using treated wastewater. Sufficient amount of water to transfer to electric power and the selection of proper location are two essential elements for the construction of small hydro-power facility. Preliminary analysis based on site visit and existing data in Gumi STP were made. Capacity of the small hydro-power plants and exact location were determined by geomorphological condition and flow duration characteristics. Flow duration characteristics and its duration curve were identified using monthly rainfall data in Gumi STP. Relevant facts of small hydro-power system in other STP were referred to adopt to Gumi STP situation. Flowrate of treated effluents and effective head between flow chamber and the location of hydraulic turbine in Gumi STP are found to be $3.70m^3$/sec and 3.5m respectively. Electric generation rate based on this feasibility study was estimated to be 86.3kW/h. Yearly electric generation rate was expected to be 932.4MMh. Proposed small hydro-power plant construction in Gumi STP is to be reasonable.

Preliminary Report of Three-Dimensional Reconstructive Intraoperative C-Arm in Percutaneous Vertebroplasty

  • Shin, Jae-Hyuk;Jeong, Je-Hoon
    • Journal of Korean Neurosurgical Society
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    • v.51 no.2
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    • pp.120-123
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    • 2012
  • Objective : Percutaneous vertebroplasty (PVP) is usually carried out under three-dimensional (2D) fluoroscopic guidance. However, operative complications or bone cement distribution might be difficult to assess on the basis of only 2D radiographic projection images. We evaluated the feasibility of performing an intraoperative and postoperative examination in patients undergoing PVP by using three-dimensional (3D) reconstructive C-arm. Methods : Standard PVP procedures were performed on 14 consecutive patients by using a Siremobil Iso-$C^{3D}$ and a multidetector computed tomography machine. Post-processing of acquired volumetric datasets included multiplanar reconstruction (MPR) and surface shaded display (SSD). We analyzed intraoperative and immediate postoperative evaluation of the needle trajectory and bone cement distribution. Results : The male : female ratio was 2 : 12; mean age of patients, 70 (range, 77-54) years; and mean T score, -3.4. The mean operation time was 52.14 min, but the time required to perform and post-process the rotational acquisitions was 7.76 min. The detection of bone cement distribution and leakage after PVP by using MPR and SSD was possible in all patients. However, detection of the safe trajectory for needle insertion was not possible. Conclusion : 3D rotational image acquisition can enable intra- or post-procedural assessment of vertebroplasty procedures for the detection of bone cement distribution and leakage. However, it is difficult to assess the safe trajectory for needle insertion.

Improvement Direction for Feasibility Analysis of Water Resources Projects by Analyzing Preliminary Feasibility Analysis Projects (예비타당성조사 사례분석을 통한 수자원사업 타당성분석의 개선방향 설정)

  • You, Jae-Young;Kim, Gil-Ho;Yeo, Kyu-Dong;Shim, Myung-Pil
    • Proceedings of the Korea Water Resources Association Conference
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    • 2008.05a
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    • pp.1545-1549
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    • 2008
  • 최근 이상홍수나 가뭄과 같은 물 관련 재해의 발생빈도가 높아지고, 산업 고도화, 인구증가와 같은 원인에 의해 장 단기적 물 부족 현상이 우려되면서 수자원 사업에 대한 관심이 고조되고 있다. 대부분의 수자원 사업은 공공성이 매우 크기 때문에 대규모 정부예산의 투입을 필요로 하고 있으나, 수자원사업의 특성상 사업의 공공성에 반하여 사업 시행에 따른 여러 경제적, 정책적 이해관계가 난립하여 사업 시행에 어려움이 따르고 있는 것이 실정이다. 이에 따라 '수자원(댐)부문사업의 예비타당성조사 표준지침 연구-제3판'에서는 수자원 사업의 타당성 평가를 위해 크게 경제성분석과 정책적분석의 두 부문으로 접근하고 있으며, 최종적으로 다기준의사결정기법 중 하나인 AHP기법을 이용하여 결정함으로써 수자원 사업의 가치 평가에 대한 이해를 돕고 있다. 본 연구에서는 지난 1999년부터 2006년까지 수행된 수자원분야 및 타분야의 사례를 바탕으로 수자원사업 예비타당성조사의 실태를 파악함으로써 현재 지적되고 있는 문제점을 고찰하고 그에 따른 해결방향을 제시하고자 하였다.

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Pre-feasibility Study in Mongolia Tavan Tolgoi Coal Bed Methane (Tavan Tolgoi Coal Bed Methane에 대한 몽골에서의 타당성 조사)

  • CHO, WONJUN;YU, HYEJIN;LEE, JESEOL;LEE, HYUN CHAN;JU, WOO SUNG;LIM, OCKTAEK
    • Transactions of the Korean hydrogen and new energy society
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    • v.29 no.1
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    • pp.124-129
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    • 2018
  • Methane is the cleanest fuel and supplies by many distributed type: liquefaction natural gas (LNG), compressed natural gas (CNG), and pipeline natural gas (PNG). Natural gas is mainly composed by methane and has been discovered in the oil and gas fields. Coal bed methane (CBM) is also one of them which reserved in coalbed. This significant new energy sources has emerge to convert an energy source, hydrogen and hydrogen-driven chemicals. For this CBM, this paper was written to analyze the geological analysis and reserves in Mongolian Tavan Tolgoi CBM coal mine and to examine the application field. This paper is mainly a preliminary feasibility report analyzing the business of Tavan Tolgoi CBM and its exploitable gas.

Development of Superconducting Low-frequency Gravitational-wave Telescope (SLGT): Technical Challenge and Feasibility

  • Lee, Yong Ho;Ahn, Sang-Hyeon;Bae, Yeong-Bok;Kang, Gungwon;Kim, Chunglee;Kim, Whansun;Oh, John J.;Oh, Sang Hoon;Park, Chan;Son, Edwin J.;Paik, Ho Jung
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.2
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    • pp.52.2-52.2
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    • 2017
  • Recent success of gravitational wave (GW) detection by LIGO opened a new window to expand our understanding of the Universe. In addition to LIGO, several other developments are going on or under planning. However, each of these detectors has a specific sensitive frequency range. There is a missing frequency band, 0.1-10 Hz, where detectors loose sensitivity significantly due to Newtonian noise on the Earth. We introduce a plan to develop a Superconducting Low-frequency Gravitational- wave Telescope (SLGT), which can observe massive black holes in 0.1-10 Hz. The SLGT system consists of magnetically levitated six test masses, superconducting quantum interference devices (SQUIDs), rigid support frame, cooling system, vibration isolation, and signal acquisition. By taking the advantage of nearly quantum-limited low-noise SQUIDs and capacitor bridge transducers, SLGT's detection sensitivity can be improved to allow astrophysical observation of black holes in cosmological distances. We present preliminary design study and expected sensitivity, and its technical feasibility.

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Development of a Nasogastric Tube Feeding Algorithm to Prevent Aspiration Pneumonia (흡인성 폐렴 예방을 위한 비위관 영양 알고리즘 개발)

  • Lee, Hye Jin;Kim, Dong-Hee
    • Journal of Korean Critical Care Nursing
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    • v.7 no.1
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    • pp.1-10
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    • 2014
  • Purpose: The purpose of this study was developing a nasogastric tube feeding algorithm to prevent aspiration pneumonia. Methods: The algorithm was developed through a methodological design. First, a pilot study was performed to determine the incidence of pneumonia. The second step was development of a preliminary algorithm through a literature review and collection of nurse opinions. The third step was to establish content validity using a panel of 12 experts. The fourth step was revision of the algorithm. Next, 20 intensive care unit nurses applied the revised algorithm for six months to their actual treatment, and the practical feasibility was verified after that. Results: In the patients for whom this algorithm was applied, no cases of pneumonia occurred. The algorithm that was developed by the present author was suitable for clinical application. Conclusion: The effect and practical feasibility of the algorithm was tested with a few patients in this study. The effect of this algorithm should be examined by applying it to more patients on an ongoing basis.

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