• International Journal of Fluid Machinery and Systems
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• 제10권3호
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• pp.197-208
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• 2017

When Francis turbines operate at partial load, residual swirl in the draft tube causes low-frequency pulsation of pressure and power output. Scale effects and system response may bias the prediction of prototype behavior based on laboratory tests, but could be overcome by means of a 1D analytical model. This paper deals with the two most important features of such a model, the compliance and the source of excitation. In a distributed-parameter version, compliance should be represented as an exponential function of local pressure. Lack of similarity due to different Froude number can thus be compensated. The normally unknown gas content in the vortex cavity has significant influence on the pulsation, and should therefore be measured and considered as a test parameter.

• 한국중재학회지:중재연구
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• 제16권3호
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• pp.53-89
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• 2006

At its thirty-second session(Vienna, 17 May-4 June 1999), the UNCITRAL decided that the priority items for the Working Group(Arbitration and Conciliation) should include enforceability of interim measures and the requirement of written (on for the arbitration agreement. The Working Group, at its forty-third session(Vienna, 3-7 October 2005), it had undertaken a detailed review of the text of the revised article 17 of UNCTTRAL Model Law on International Commercial Arbitration, and it had resumed discussions on a draft model legislative provision revising article 7, paragraph (2) of UNCITRAL Model Law. The purpose of this paper is to make research on the contents and issues of the draft legislative provisions on interim measures and preliminary orders, and on the form of arbitration agreement which the Working Group discussed and adopted at its forth-fourth session(New York, 23-27 January 2006). The draft legislative provisions on interim measures and preliminary orders are composed of the following provisions : Article 17-power of arbitral tribunal to order interim measures; article 17 bis-conditions for granting interim measures; article 17 ter-applications for preliminary orders and conditions for granting preliminary orders; article 17 quater-specific regime for preliminary orders; article 17 quinquies- modification, suspension, termination; article 17 sexies-provision of security; article 17 septies-disclosure; article 17 octies-costs and damages; article 17 novies recognition and enforcements; article 17 decies-grounds for refusing recognition or enforcement; article 17 undecies-court-ordered interim measures. There are the following issues in the draft legislative provisions on interim measures and preliminary orders : form of issuance of an interim measures in article 17(2); conditions for granting interim measures in article 17 bis; purpose, function and legal regime of preliminary orders in article 17 ter; obligation of arbitral tribunal to give notice, and non-enforceability of preliminary orders in article 17 quater; burden of proof, interplay between article 17 decies and article 34, and decision on the recognition and enforcement of the interim measures in article 17 decies; placement of article 17 undecies; amendment of scope exception of application in article 1(2). The draft legislative provisions on the form of arbitration agreement are composed of the following provisions : article 7(1) definition of arbitration agreement; article 7(2) arbitration agreement in writing; article 7(3) arbitration agreement if its terms(content) are (is) recorded in any form; article 7(4) arbitration agreement by an electronic communication; article 7(5) arbitration agreement in an exchange of statements of claim and defence; article 7(6) reference to any document containing an arbitration clause. There are the following issues in the draft legislative provisions on the form of arbitration agreement : arbitration agreement in writing in article 7(2); terms or contents of arbitration agreement in article 7(3); arbitration agreement by electronic communication in article 7(4); existence of arbitration agreement in article 7(5); reference to any document containing an arbitration clause in article 7(6); the alternative proposal on article 7; amendment to article 35(2).

• 전기학회논문지P
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• 제61권4호
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• pp.153-160
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• 2012

This paper is written for the development of boiler combustion air control algorithm of coal-fired power plant by the steps of design, coding and test. The control algorithms were designed in the shape of cascade control for two parts of air master, forced draft fan pitch blade by standard function blocks. This control algorithms were coded to the control programs of distributed control systems under development. The simulator for coal-fired power plant was used in the test step and automatic control, sequence control and emergency stop tests were performed successfully like the tests of the actual power plant. The reliability will be obtained enough to apply to actual site if the total test has been completed in the state that all algorithms were linked mutually. It is expected that the project result will contribute to the safe operation of domestic power plant and the self-reliance of coal-fired power plant control technique.

• 농업과학연구
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• 제49권4호
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• pp.677-696
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• 2022

Development of radish collectors may enhance radish production and promote upland crop mechanization in the Republic of Korea. Theoretical analysis of power is crucial to ensure the optimum design of agricultural machinery. The aim of the present study is to analyze theoretically the power requirement of a tractor-mounted radish collector under development and to propose design guidelines. The important components of the radish collector were belt-type conveyors, three hydraulic motors, and a direct current (DC) winch motor to operate the total radish collecting process. Theoretical equations were used to calculate the hydraulic motor's power, winch motor power, and draft power at loaded and unloaded conditions. A variety of tractors (44 - 74 kW) and different soil characteristics (hard, firm, tilted, and sandy) were considered to investigate the appropriate drawbar power. Variations of the power requirement of the tractor-mounted radish collector were observed due to modifications of the design parameters. The required hydraulic power of the stem cutting conveyor, stem cutting blade, and transfer conveyor of the radish collector were 0.23 and 0.24, 0.18 and 0.19, and 0.19 and 0.22 kW under unloaded and loaded conditions, respectively. The maximum draft power was calculated as 0.89, 1.07, 1.25, and 1.61 kW at a 30° tilted angle for hard, firm, tilted, and sandy soil, respectively. The calculation showed 2.07 kW DC power was required for unfolding or folding the stem-cutting conveyor. A maximum power of 4.78 kW was prescribed for conducting the whole process of the tractor-mounted radish collector. The analysis of power introduced in this study will be helpful to select the appropriate design parameters for the successful development of a tractor-mounted radish collector.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 전력전자학술대회
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• pp.424-425
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• 2018

In the introduction, this paper introduces LS Industrial Systems' medium-voltage drive installed at Hyundai Green Power, an 800MW gas power plant. In the body, it explains the synchronous transfer technology and new speed search technology applied to Forced Draft(FD) Fan and Boiler Feed-water(BF) Pump, which are power generation facilities. Lastly, it shows the annual energy saving amount and operation status which are applied to each facility and proves that it is a successful application case.

• 한국해양공학회지
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• 제34권5호
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• pp.294-303
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• 2020

This study discusses data collection, calculation of wind and wave-induced resistance, and speed-power analysis of an 8,600 TEU container ship. Data acquisition system of the ship operator was improved to obtain the data necessary for the analysis, which was accomplished using SPA (Ship Performance Analysis, Park et al., 2019) in conformation with ISO15016:2015. From a previous operation profile of the container, the standard operating conditions of mean draft were 12.5 m and 13.6 m, which were defined with the mean stowage configuration of each condition. Model tests, including the load-variation test, were conducted to validate new ship performance and for the speed-power analysis. The major part of the added resistance of container ship is due to the wind. To check the reliability of wind-resistance calculation results, the resistance coefficients, added resistance, and speed-power analysis results using the Fujiwara regression formula (ISO15016:2015) and Computational fluid dynamics (Ryu et al., 2016; Jeon et al., 2017) analysis were compared. Wind speed and direction measured using an anemometer were used for wind-resistance calculation and the wave resistance was calculated using the wave-height and direction-data from weather information. Also, measured water temperature was used to calculate the increase in resistance owing to the deviation in water density. As a result, the SPA analysis using measured data and weather information was proved to be valid and able to identify the ship's resistance propulsion performance. Even with little difference in the air-resistance coefficient value, both methods provide sufficient accuracy for speed-power analysis. The differences were unnoticeable when the speed-power analysis results using each method were compared. Also, speed-power analysis results of the 8,600 TEU container ship in two draft conditions show acceptable trends when compared with the model test results and are also able to show power increase owing to hull fouling and aging. Thus, results of speed-power analysis of the existing 8,600 TEU container ship using the SPA program appropriately exhibit the characteristics of speed-power performance in deal conditions.

• 동력기계공학회지
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• 제17권2호
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• pp.103-107
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• 2013

The structure of a variable liquid column oscillator(a VLCO) is analogous to that of the tuned liquid column damper used to suppress oscillatory motion in large structures like tall buildings and cargo ships. The VLCO is a system absorbing high kinetic energy of accelerated motions of multiple floating bodies in the effect of air springs occurred by installation of inner air chambers. Thus, VLCO can improve the efficiency of energy than wave energy converters of the activating object type made in Pelamis Company. In this research, the experiment was performed that a simple floating body was filled with internal fluid of same draft. The characteristics of motions were evaluated in each case of the opening or closing of the upper valves.

• 동력기계공학회지
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• 제18권3호
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• pp.36-41
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• 2014

The structure of a variable liquid column oscillator(a VLCO) is analogous to that of the tuned liquid column damper used to suppress oscillatory motion in large structures like tall buildings and cargo ships. The VLCO is a system absorbing high kinetic energy of accelerated motions of the multiple floating bodies in the effect of air springs occurred by installation of inner air chambers. Thus, VLCO can improve the efficiency of energy than wave energy converters of the activating object type made in Pelamis Company. In this research, the experiment was performed in two models of same draft. The one is that weights were filled, and the other is that water was filled. The numerical results were estimated by assuming that do not exist internal flow, and the results were compared with the results of experiments.

• 문화기술의 융합
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• 제8권2호
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• pp.197-202
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• 2022

성 중립 징병제는 인구절벽 시대에서 군이 요구하는 인력 수준을 유지하고 양성평등의 개념을 확대할 수 있는 제도이다. 유럽 최초로 성 중립 징병제를 시행한 노르웨이의 사례를 통해 선택적 징병제 검토 필요성, 양성평등을 위한 군내 조직문화 개선 필요성 등 한국군에 주는 시사점을 도출해보았다. 여성의 사회참여 확대와 인권향상으로 전통적 남성의 영역이었던 군도 여성에게 개방되는 속도가 빨라지고 있다. 다만, 우리나라에 징병제를 여성까지 확대하기 위해서는 필요한 제반 시설, 복무기간, 급여수준, 전투력 유지 등에 대한 각종 우려를 극복해야 할 것이다. 국가가 처한 안보환경과 여성의 사회참여 정도, 국가내 소수자들의 처우 등이 모두 다르기에 우리도 성 중립 징병제를 시행하는 것이 옳다는 결론을 내리기는 어렵다. 그렇지만 미래를 대비하는 국가전략은 결론이 쉽게 나오지 않고 결론이 불편한 진실이라고 해서 멈출 수 없기에 이 논문을 시작으로 여성을 징병제에 포함하는 방안에 대한 건전한 담론이 형성되길 기대한다.

• 전기학회논문지P
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• 제62권3호
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• pp.117-126
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• 2013

This paper is written for the development and application of boiler furnace pressure control algorithm and distributed control system of coal-fired power plant by the steps of design, coding, simulation test, site installation and site commissioning test. The control algorithms were designed in the shape of cascade control for two parts of furnace pressure control and induced draft fan pitch blade by standard function blocks. This control algorithms were coded to the control programs of distributed control systems. The simulator for coal-fired power plant was used in the test step and automatic control, sequence control and emergency stop tests were performed successfully like the tests of the actual power plant. The reliability was obtained enough to be installed at the actual power plant and all of distributed control systems had been installed at power plant and all signals were connected mutually. Tests for reliability and safety of plant operation were completed successfully and power plant is being operated commercially. It is expected that the project result will contribute to the safe operation of domestic new and retrofit power plants, the self-reliance of coal-fired power plant control technique and overseas business for power plant.