• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2011년도 학술발표회
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• pp.20-20
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• 2011

The purpose of this research aims to evaluate the emergence of new business mode in the Chinese water market since the mid-2000s - Transfer-Operate-Transfer(TOT) Projects. The study pays special attention to the case of the Hefei Wangxiaoying Wastewater Treatment TOT Project, which was awarded to the consortium of Berlin Water International and its Chinese partner in late 2004. The consortium secured an exclusive operating right for 23 years on the basis of a TOT scheme and would take responsibility of all the profits and losses in the operation of the plant. The total investment for the transfer amounted to RMB 491 million(US$70 million). The price was more than 288% of the original value, RMB 170 million (US$24 million). The project can be regarded as a successful case because of the following three causes. First, the Hefei government followed a series of standardized procedures in the international bidding, which ignited best-performed international players' competition for the project. Second, the project will bring in cutting-edge operation skills and management know-how. Third, the government succeeded in raising public asset values, and thanks to this, the government is able to consider other similar projects not only in the water sector but also other sectors in public utility services. Nevertheless, Berlin Water's point of view, there are several challenges. First, the company took a risk to pay such a large amount of cash to the Hefei government. Although such premium can be recouped in the operation period of 23 years, whether or not the company would be able to recover the initial investment and realize profits is in question due to an uncertainty of socio-political circumstances in China. Second, Berlin Water should expect a steep rise of water tariffs over the contract period in order to get the investment back. Water pricing is still a sensible matter to Chinese authorities, and therefore, it is uncertain if such rise of water tariffs would be possible. Third, the TOT mode leads to creation of a large amount of cash to government officials, which might have caused corruption between those who are involved in TOT deals. Then, the final contract fee would soar, which often results in the burden of normal customers. As discussed, the TOT mode has drawn much attention of foreign investors as a new alternative to enter into the Chinese water market. But it is important to note that foreign investors should be aware of possible risks in water TOT projects, which reflects some features of the Chinese political economy landscape and social norms. The Hefei case indicates that benefits can overshadow risks in TOT projects, which will continue to attract foreign investors that are dedicated to establishing their strongholds in the Chinese water market.

• 전기학회논문지
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• 제65권1호
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• pp.73-80
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• 2016

The preliminary test for the dual mode plasma torch system was carried out to explore the operation properties in advance. The dual mode plasma torch system that is able to operate in transferred, non-transferred, or dual mode is very adequate for melting the mixed wastes including nonconductive materials such as concrete, asbestos, etc. since it exploits both the high efficiency of heat transfer to the melt in transferred mode and stable operation in non-transferred mode. Also, system operation including restarting is reliable and very easy. A stationary melter with a refractory structure was designed and manufactured considering the melting behavior of slags to minimize the refractory erosion. The power supply for the dual mode plasma torch system built with high power insulated gate bipolar transistor (IGBT) modules has functions for both current control and voltage control and is sufficient to suppress the harmonics during the operation of the plasma torch. The power supply provides two different voltages for transferred operation and non-transferred. It is confirmed that the operation voltage in transferred is always higher than non-transferred. The dual mode plasma torch system was successfully developed and is under operation for a melting experiment to optimize operation data.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3395-3400
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• 2007

Heat transfer experiments at a vertical annulus passage were carried out in the SPHINX(Supercritical Pressure Heat Transfer Investigation for NeXt Generation) to investigate the heat transfer behaviors of supercritical $CO_2$. The collected test data are to be used for the reactor core design of the SCWR (SuperCritical Water-cooled Reactor). The mass flux was in the range of 400${\sim}$1200 kg/$m^2$s and the heat flux was chosen up to 150 kW/$m^2$. The selected pressures were 7.75 and 8.12 MPa. The heat transfer data were analyzed and compared with the previous tube test data. The test results showed that the heat transfer characteristics were similar to those of the tube in case of a normal heat transfer mode and degree of heat transfer deterioration became smaller than that in the tube. Comparison of the experimental heat transfer coefficients with the predicted ones by the existing correlations showed that there was not a distinct difference between the correlations.

• 전자공학회논문지B
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• 제30B권9호
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• pp.36-44
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• 1993

In the development of a high speed and light weight manipulator, it is necessary to consider the flexibility of a robotic arm. The infinite dynamics must be analyzed to obtain the finite mode modeling to achieve the feasible controller design of the robotic arm. The modeling procedures of the flexible robot arm, and natural frequencies and mode shapes by the constrained and unconstrained mode method are illustrated. The transfer function of the robot arm with a payload is also shown. The controller is designed by the pole assignment and optimal control theory to compensate for the unmodelled dynamic effects to the low order system. Also, the pole assignment method involving the harmonic vibration mode is presented through computer simulation.

• 전자공학회논문지S
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• 제35S권4호
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• pp.128-138
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• 1998

This paper describes a principle of the conducted noise separator which can separate the conducted noise to the common mode and differential mode(normal mode), and presents the transfer characteristics of the separator designed and manufactured. We separated the conducted noise generated from switched mode converter to the CM and DM conducted noise, and also analyzed the source and path of conducted noise in the converter by the conducted noise separator. Since we could easily get the characteristics of the CM and DM conducted noise by the separator, we could efficiently determine the contermeasures for the reduction of the conducted noise and establish the foundation of the systematic procedure for the design of low pass filter.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.474-476
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• 1999

This paper presents the vector control of induction motor for traction drives. Especially, the PWM mode control method is well described to be selected as the change of speed to meet the wide speed range of the traction motor. Asynchronous space vector PWM mode and synchronous one pulse mode are basically used under the full speed range with the overmodulation PWM mode for the soft transfer between them. The validity of this proposed control scheme is verified with the simulation results.

• Journal of Mechanical Science and Technology
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• 제17권6호
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• pp.805-815
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• 2003

In order to execute efficiently the free vibration analysis of 2-dimensional structures like plate structures, the author developed the finite element-transfer stiffness coefficient method. This method is based on the combination of the modeling techniques in the FEM and the transfer technique of the stiffness coefficient in the transfer stiffness coefficient method. Numerical results of the simply supported and the elastic supported rectangular plates showed that the present method can be successfully applied to the free vibration analysis of plate structures on a personal computer. We confirmed that, in the case of analyzing the free vibration of rectangular plate structures, the present method is superior to the FEM from the viewpoint of computation time and storage.

• 대한기계학회논문집
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• 제15권2호
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• pp.455-462
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• 1991

This paper present an analysis method of crankshaft of four cylinder internal combustion engine for studying dynamic characteristics of the shaft. For simple analysis, uniform sections of journal, pin and arm parts were assumed. Transfer Matrix Method was used, considering branched part and coordinate transformation part. Natural frequencies, natural modes and transfer functions of crank shaft were investigated based upon the Timosenko beam theory: It was shown that the calculated natural frequencies, modeshapes agree well with the experimental results.

• Journal of Welding and Joining
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• 제11권1호
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• pp.73-79
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• 1993

The phenomenon of metal transfer has been investigated for different transfer modes using a digital high speed motion analyzer and an arc shadow-graphing system based on a laser source and related optical system. It was observed that the pinch instability phenomenon did not occur for the globular transfer mode, since the liquid globule was then spherical rateher than a cylindrical liquid bar. On increasing the ratio of carbon dioxide to argon, the transition current from globular to spray transfer generally increased, but it is interesting that the transition was observed to occur at the lowest current in a 5% CO$_{2}$-95% argon gas mixture. For pure carbon dioxide and helium shielding gases, the drop frequency increased slowly with increasing current. At high currents or an argon based shielding gas, the length of liquid bar decreased as the carbon dioxide content increased. The acceleration of a droplet within the arc was determined using the gas drag force theory and was found to be greater than the experimental results.

• 한국소음진동공학회논문집
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• 제12권2호
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• pp.161-169
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• 2002

Based on the analytic expression for the elasto-dynamic behavior of rotating shaft, the transfer matrix is formulated for the shaft element with uniform cross-section. Timoshenko beam theory is Introduced for modeling the behavior of shaft. Complex variables representing the displacement, slope, moment and shear force are used for deriving the transfer matrix between both ends of the shaft element. Simulation result obtained by applying the transfer matrix to a general rotor model is compared with the reference result and proved to be exact. Natural frequencies and the corresponding modes are analyzed with varying the bearing: stiffness. The generally used bearings are considered for discussions. and the bearing stiffness is shown to affect the vibration characteristics of rotor.