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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korea Society For Power System Engineering
Journal Basic Information
Journal DOI :
The Korea Society for Power System Engineering
Editor in Chief :
Volume & Issues
Volume 17, Issue 6 - Dec 2013
Volume 17, Issue 5 - Oct 2013
Volume 17, Issue 4 - Aug 2013
Volume 17, Issue 3 - Jun 2013
Volume 17, Issue 2 - Apr 2013
Volume 17, Issue 1 - Feb 2013
Selecting the target year
A Review on Nano Applications: Fluids and Heat Transfer
Yoon, Yong-Han ; Shim, JaeSool ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 3~12
DOI : 10.9726/kspse.2013.17.5.003
Physicochemical Characteristics Based on Hydrothermal Aging of Prepared DOC
Seo, Choong-Kil ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 13~22
DOI : 10.9726/kspse.2013.17.5.013
This paper reports the investigation of the physical and chemical characteristics of the prepared 3Pt-2MgO-
DOC, based on its hydrothermal aging. As a result of impregnating and reducing the
precursor on a
basis, it was well dispersed into small particles with the range 2-3nm. This was because the
acted as a barrier to prevent movement of the catalyst particles. For a hydrothermally aged catalyst for 9h at
, its performance when purifying harmful gases decreased compared to a fresh catalyst, but its specific surface area was at the same level. This was because the performance of the catalyst was reduced by the sintering of the precious metal Pt, rather than by washcoat sintering and pore clogging. For an excessively hydrothermally aged catalyst for 9h at
, Pt grew into an approximately 50nm class, formed a cluster compared to a fresh catalyst. The
promoters also formed clusters among components of the same type, reducing their specific surface area to
, which was 14% less than a fresh catalyst.
The Structural Characterization of Pristine and Ground Graphenes with Different Grinding Speed in Planetary Ball Mill
Lee, Tae-Jin ; Munkhshur, Myekhlai ; Tanshen, Md. Riyad ; Lee, Dae-Chul ; Chung, Han-Shik ; Jeong, Hyo-Min ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 23~29
DOI : 10.9726/kspse.2013.17.5.023
The activation process is the key to graphene`s practical application. In this study, the effect of grinding speed in planetary ball mill on structural integrity of graphene has been studied at various grinding speed such as 100 rpm, 200 rpm, 300 rpm, 400 rpm and 500 rpm. The morphology and structure of pristine graphene and ground graphenes were studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy respectively. According to these results, structural properties of graphene were improved when grinding speed was increased.
Numerical Analysis on Freezing in the Ship Voyaging in Polar Regions
Kang, Ho-Keun ; Kim, Ki-Pyoung ; Ahn, Soo-Whan ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 30~37
DOI : 10.9726/kspse.2013.17.5.030
For vessels operating in the cold climate regions, the ballast water inside or hopper tanks above the waterline may be frozen, starting at the top of the tank and at the side walls. Therefore, countermeasures against freeze-up of the ballast tank such as air-bubbling system, hot steam injecting system, heating coil system and water circulating system are taken to prevent freeze-up phenomenon; however, there are no rigorous investigations of anti-freezing to examine the effectiveness and validity of systems against freeze-up of the ballast tank, in which the temperatures are about -
(ambient air temperature) and
(sea water), respectively. In this paper, to ensure reasonable specifications for cold regions if the measures from the above-mentioned systems against freeze-up are effective, the phenomenon of ballast tank freeze-up is simulated and discussed in low temperature conditions. With the results using the commercial CFD code, CFX 14, the most cost-effective solution is conducted to prevent being frozen along the outer surface.
Study on Wave Energy Generation of Multi-Floating Bodies for Energy Absorption by CFD
Li, Kui-Ming ; Choi, Yoon-Hwan ; Lee, Yeon-Won ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 38~43
DOI : 10.9726/kspse.2013.17.5.038
In order to design a wave energy generating system, a 6-DOF analysis technique is applied to CFD analysis on of a floating body and the behavior is interpreted according to the nature of the incoming waves. A spring constant is adopted to control the motion of multi floating bodies and to calculate the total average power absorption. Three cases of different wavelengths namely 20D, 30D and 40D have been modeled to analyze the total average power absorption. The average power absorption not only varies with the position of the floating body but also varies with wavelength. From the results obtained, it is concluded that the maximum total average power absorption is 9W approximately in wavelength 30D and the minimum total average power absorption is 4.3W approximately in wavelength 40D.
Barrier-Transition Cooling in LED
Kim, Jedo ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 44~51
DOI : 10.9726/kspse.2013.17.5.044
This paper proposes and analyzes recycling of optical phonons emitted by nonradiative decay, which is a major thermal management concern for high-power light emitting diodes (LED), by introducing an integrated, heterogeneous barrier cooling layer. The cooling is proportional to the number of phonons absorbed per electron overcoming the potential barrier, while the multi-phonon absorption rate is inversely proportional to this number. We address the theoretical treatment of photon-electron-phonon interaction/transport kinetics for optimal number of phonons (i.e., barrier height). We consider a GaN/InGaN LED with a metal/AlGaAs/GaAs/metal potential barrier and discuss the energy conversion rates. We find that significant amount of heat can be recycled by the barrier transition cooling layer.
Exergy analysis of R717 high-efficiency OTEC power cycle for the efficiency and pressure drop in main components
Yoon, Jung-In ; Son, Chang-Hyo ; Yang, Dong-Il ; Kim, Hyeon-Uk ; Kim, Hyeon-Ju ; Lee, Ho-Saeng ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 52~57
DOI : 10.9726/kspse.2013.17.5.052
In this paper, an analysis on exergy efficiency of high-efficiency R717 OTEC power system for the efficiency and pressure drop in main components were investigated theoretically in order to optimize the design for the operating parameters of this system. The operating parameters considered in this study include turbine and pump efficiency, and pressure drop in a condenser and evaporator, respectively. As the turbine efficiency of R717 OTEC power system increases, the exergy efficiency of this system increases. But pressure drop in the evaporator of R717 OTEC power system increases, the exergy efficiency of this system decreases, respectively. And, in case of exergy efficiency of this OTEC system, the turbine efficiency and pressure drop in a condenser on R717 OTEC power system is the largest and the lowest among operation parameters, respectively.
The Effect of Thermal Diffusivity on the System Efficiency of a DOTEC Cycle
Yoon, Jung-In ; Choi, Kwang-Hwan ; Kwakye-Boateng, Patricia ; Son, Chang-Hyo ; Kim, Hyeon-Ju ; Lee, Ho-Saeng ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 58~63
DOI : 10.9726/kspse.2013.17.5.058
In this study, the effect of deep ocean condenser inlet temperature (
), condenser inlet pressure (
), and thermal diffusivity on system efficiency of some selected refrigerants was analyzed using HYSYS. The proposed DOTEC cycle is similar to the reheat Rankine cycle but eliminates irreversibilities by bleeding a fraction of the steam between certain stages of the turbine. The evaporator inlet mass flow rate, inlet temperature of turbine 1, turbine efficiency and inlet and outlet temperature of heat source were imposed. The working fluids considered are sorted in ascending order of their molecular weights as R717, R600a and R152a. Results indicated that a fluid with a lower boiling point temperature like R717 needs a corresponding high heat source and/or evaporator inlet pressure. Also, the response of thermal diffusivity closely follows the change in TDOI as an increase in
which reduces thermal diffusivity and system efficiency. Furthermore, the fluid with the nominal boiling point temperature has the highest efficiency with efficiency decreasing with an increase in TDOI.
A Study on the Optimization of Water Balance Control in the Intermittent PEM Fuel Cell
Choi, Kwang-Hwan ; Yoon, Jung-In ; Son, Chang-Hyo ; Hong, Boo-Pyo ; Bakhtiar, Agung ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 64~68
DOI : 10.9726/kspse.2013.17.5.064
One of the water management goals in PEM fuel cell is to avoid flooding and drying in the membrane, therefore the air humidification process is required. In order to increase water removal out of the membrane, the water management system may require the dehumidification process and it also requires a large space for application, moreover the process time is slow. In conformity with this fact, this present study proposes an advanced dynamic fuel cell water management which can be an intermittent optimization control using air flow rate instead of the air humidity as an variable in the optimization process. The results of this study have shown that the membrane flooding and drying can be avoided after being assisted by air velocity controlling method.
Mechanical properties of TiO
/epoxy resin nanocomposites
Ahn, Seok-Hwan ; Nam, Ki-Woo ; Moon, Chang-Kwon ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 69~77
DOI : 10.9726/kspse.2013.17.5.069
The purpose of this study is to improve the properties of epoxy resin using the big-sized titanium oxide nanoparticles. The effects of particle weight fraction and shape of sample on the thermal and mechanical properties in titanium oxide reinforced epoxy resin has been investigated. In addition, the effect of particle dispersion situation on the mechanical properties of nanocomposites has been studied. As a result, the Tg was almost same regardless of the content of nanoparticles. Storage modulus increased up to the content of 3wt% particles and then decreased. Tensile strength and modulus of film-shaped sample with 1wt% was higher than the one of pure epoxy, while other composites were not. The tensile strength of dogbone-shaped sample with 1wt% was only higher than the one of pure epoxy, while other composites were lower than the one of pure epoxy. Tensile modulus of dogbone-shaped samples increased with the content of particles.
Study on the heat transfer properties of raw and ground graphene coating on the copper plate
Lee, Sin-Il ; Tanshen, Md.R. ; Lee, Kwang-Sung ; Munkhshur, Myekhlai ; Jeong, Hyo-Min ; Chung, Han-Shik ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 78~85
DOI : 10.9726/kspse.2013.17.5.078
A high thermal conductivity material, namely graphene is treated by planetary ball milling machine to transport the heat by increasing the temperature. Experiments were performed to assess the heat transfer enhancement benefits of coating the bottom wall of copper substrate with graphene. It is well known that the graphene is unable to disperse into base fluid without any treatment, which is due to the several reasons such as attachment of hydrophobic surface, agglomeration and impurity. To further improve the dispersibility and thermal characteristics, planetary ball milling approach is used to grind the raw samples at optimized condition. The results are examined by transmission electron microscopy, x-ray diffraction, Raman spectrometer, UV-spectrometer, thermal conductivity and thermal imager. Thermal conductivity measurements of structures are taken to support the explanation of heat transfer properties of different samples. As a result, it is found that the planetary ball milling approach is effective for improvement of both the dispersion and heat carriers of carbon based material. Indeed, the heat transfer of the ground graphene coated substrate was higher than that of the copper substrate with raw graphene.
Optimization of PI Controller Gain for Simplified Vector Control on PMSM Using Genetic Algorithm
Jeong, Seok-Kwon ; Wibowo, Wahyu Kunto ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 86~93
DOI : 10.9726/kspse.2013.17.5.086
This paper proposes the used of genetic algorithm for optimizing PI controller and describes the dynamic modeling simulation for the permanent magnet synchronous motor driven by simplified vector control with the aid of MATLAB-Simulink environment. Furthermore, three kinds of error criterion minimization, integral absolute error, integral square error, and integral time absolute error, are used as objective function in the genetic algorithm. The modeling procedures and simulation results are described and presented in this paper. Computer simulation results indicate that the genetic algorithm was able to optimize the PI controller and gives good control performance of the system. Moreover, simplified vector control on permanent magnet synchronous motor does not need to regulate the direct axis component current. This makes simplified vector control of the permanent magnet synchronous motor very useful for some special applications that need simple control structure and low cost performance.
A Positioning Mooring System Design for Barge Ship Based on PID Control Approach
Kim, Youngbok ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 94~99
DOI : 10.9726/kspse.2013.17.5.094
This paper presents some experimental results about Position Mooring (PM) system applied to the barge ship. In PM operation, the station keeping in surge, sway of vessel is provided by the mooring system. In this paper, a system, consisting of a barge vessel and mooring lines, is mathematically modeled. The position and orientation of vessel is controlled by changing the tensions in the mooring lines. The PID control strategy is applied to evaluate the efficiency of proposed system. Experimental result which corresponds to the applied control strategy is presented and discussed.
Positioning Accuracy on Robot Self-localization by Real-time Indoor Positioning System with SS Ultrasonic Waves
Suzuki, Akimasa ; Kumakura, Ken ; Tomizuka, Daisuke ; Hagiwara, Yoshinobu ; Kim, Youngbok ; Choi, Yongwoon ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 100~111
DOI : 10.9726/kspse.2013.17.5.100
Indoor real-time positioning for multiple targets is required to realize human-robot symbiosis. This study firstly presents positioning accuracy on an autonomous mobile robot controlled by 3-D coordinates that is obtained by a real-time indoor positioning system with spread spectrum (SS) ultrasonic signals communicated by code-division multiple access. Although many positioning systems have been investigated, the positioning system with the SS ultrasonic signals can measure identified multiple 3-D positions in every 70 ms with noise tolerance and error within 100 mm. This system is also robust to occlusion and environmental changes. However, thus far, the positioning errors in an autonomous mobile robot, controlled by these systems using the SS ultrasonic signals, have not been evaluated as an experimental study. Therefore, a positioning experiment for trajectory control is conducted using an autonomous mobile robot and our positioning system. The effectiveness of this positioning method for robot self-localization is shown, from this experiment, because the average control error between the target position and the robot`s position at 29 mm is obtained.
Improved View-Based Navigation for Obstacle Avoidance using Ego-Motion
Hagiwara, Yoshinobu ; Suzuki, Akimasa ; Kim, Youngbok ; Choi, Yongwoon ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 112~120
DOI : 10.9726/kspse.2013.17.5.112
In this study, we propose an improved view-based navigation method for obstacle avoidance and evaluate the effectiveness of the method in real environments with real obstacles. The proposed method possesses the ability to estimate the position and rotation of a mobile robot, even if the mobile robot strays from a recording path for the purpose of avoiding obstacles. In order to achieve this, ego-motion estimation was incorporated into the existing view-based navigation system. The ego-motion is calculated from SURF points between a current view and a recorded view using a Kinect sensor. In conventional view-based navigation systems, it is difficult to generate alternate paths to avoid obstacles. The proposed method is anticipated to allow a mobile robot greater flexibility in path planning to avoid humans and objects expected in real environments. Based on experiments performed in an indoor environment using a mobile robot, we evaluated the measurement accuracy of the proposed method, and confirmed its feasibility for robot navigation in museums and shopping mall.
Distance Measurement System using A Stereo Camera and Radial Pattern Target for Automatic Berthing Control
Mizuchi, Yoshiaki ; Ogura, Tadashi ; Hagiwara, Yoshinobu ; Suzuki, Akimasa ; Kim, Youngbok ; Choi, Yongwoon ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 121~127
DOI : 10.9726/kspse.2013.17.5.121
In this paper, we propose a distance measurement system for automatic berthing control using a stereo camera mounted on a rotation control device, and a radial pattern target. Automatically controlling the position and attitude of a ship aims to prevent maritime accidents due to human error. Our goal is to measure the relative distance between a ship and an onshore or offshore target for berthing. Therefore, the distance should be continuously measured while tracking a fixed point on a target. To this end, we developed a stereo camerabased distance measurement system that satisfied these requirements. This paper describes the structure and principle of the measurement system. We validate the distance error for target incline due to the relative position and attitude between a camera and a target in miniature scale. In addition, the findings of an experiment in an outdoor environment demonstrate that the proposed measurement system has accuracy within 1 m at a range of 20-100 m which is the acceptable accuracy for automatic berthing.
A Study on the Modeling of Transient Response in Automated Manual Transmission for Hybrid Trucks
Park, Kyung-Min ; Ko, Young-Jin ;
Journal of the Korea Society For Power System Engineering, volume 17, issue 5, 2013, Pages 128~137
DOI : 10.9726/kspse.2013.17.5.128
Modern transmission technologies such as automated manual transmission(AMT) and dual clutch transmission(DCT) are interested to all manufactures due to their fuel efficiency and driver`s convenience, especially in a hybrid system. AMT has advantages in that they have a high efficiency of manual transmissions(MT) and offer operation convenience similar to automatic transmissions(AT), but it has some disadvantages in that they have torque gap during gear shift and shift time. To reduce disadvantages, it is necessary to evaluate errors and characteristics as a developing simulation model before experimental verification. The purpose of this study is to develop virtual components and simulate the transient response of AMT. A dynamic AMT model and a control logic for an integrated vehicle model have been developed using Matlab/Simulink as a simulation platform. In this paper, the clutch model to describe the stick-slip transition mode and the transmission model to describe the neutral gear shifting is introduced and compared with each other.