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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of the Korean Society of Mechanical Engineers A
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Journal DOI :
The Korean Society of Mechanical Engineers
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Volume & Issues
Volume 32, Issue 12 - Dec 2008
Volume 32, Issue 11 - Nov 2008
Volume 32, Issue 10 - Oct 2008
Volume 32, Issue 9 - Sep 2008
Volume 32, Issue 8 - Aug 2008
Volume 32, Issue 7 - Jul 2008
Volume 32, Issue 6 - Jun 2008
Volume 32, Issue 5 - May 2008
Volume 32, Issue 4 - Apr 2008
Volume 32, Issue 3 - Mar 2008
Volume 32, Issue 2 - Feb 2008
Volume 32, Issue 1 - Jan 2008
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Development of Membrane Filters with Nanostructured Porous Layer by Coating of Metal Nanoparticles Sintered onto a Micro-Filter
Lee, Dong-Geun ; Park, Seok-Joo ; Park, Young-Ok ; Ryu, Jeong-In ;
Transactions of the Korean Society of Mechanical Engineers A, volume 32, issue 8, 2008, Pages 617~623
DOI : 10.3795/KSME-A.2008.32.8.617
The membrane filter adhered with nanostructured porous layer was made by heat treatment after deposition of nanoparticle-agglomerates sintered in aerosol phase onto a conventional micron-fibrous metal filter as a substrate filter. The Sintered-Nanoparticle-Agglomerates-coated NanoStructured porous layer Membrane Filter (SNA-NSMF), whose the filtration performance was improved compared with the conventional metal membrane filters, was developed by adhesion of nanoparticle-agglomerates of dendrite structure sintered onto the micron-fibrous metal filter. The size of nanoparticle-agglomerates of dendrite structure decreased with increasing the sintering temperature because nanoparticle-agglomerates shrank. When shrinking nanoparticle-agglomerates were deposited and treated with heat onto the conventional micron-fibrous metal filter, pore size of nanostructured porous layer decreased. Therefore, pressure drops of SNA-NSMFs increased from 0.3 to 0.516 kPa and filtration efficiencies remarkably increased from 95.612 to 99.9993%.
A Study About Biochip Combined with Micro Mixer and Reactor for DNA Ligation
Kang, Do-Hyoung ; Ahn, Yoo-Min ; Hwang, Seung-Yong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 32, issue 8, 2008, Pages 624~632
DOI : 10.3795/KSME-A.2008.32.8.624
In this research, we developed new PDMS-glass based microbiochip consisted of the micromixer and microreactor for DNA ligation. The micromixer was composed of a straight channel integrated with nozzles and pillars, and the microreactor was composed of a serpentine channel. We coated the PDMS chip surface with the 0.25wt.% PVP solution to prevent the bubble generation which was caused by the hydrophobicity of the PDMS. The new micomixer was passive type and the mixing was enhanced by a convective diffusion using the nozzle and pillar. The 10.33mm long micromixer showed the good mixing efficiency of 87.7% at 500 l/min flow rate. We could perform the DNA ligation successfully in the microbiochip, and the ligation time was shortened from 4 hours in conventional laboratory method to 5 min in the microbiochip.
Theoretical Velocity Analysis of Micro Robot Based on Crawling Locomotive Mechanism for Pipe Inspection Micro Robot
Jang, Ki-Hyun ; Park, Hyun-Jun ; Kim, Byung-Kyu ;
Transactions of the Korean Society of Mechanical Engineers A, volume 32, issue 8, 2008, Pages 633~641
DOI : 10.3795/KSME-A.2008.32.8.633
Recently, the necessity for diagnosis and management of pipes has emerged as the issue due to contamination of water supply generated by corrosion of pipes. Although inspection has been performed with industrial endoscopes, the method has limits for full diagnosis of pipes due to the lack of working range. As a solution for this problem, many locomotive mechanisms for a micro robot with endoscope functions were proposed. In this paper, we analyze the locomotive mechanism of crawling robot proposed as locomotive device for pipe inspection. Based on a mechanical modeling of motor and micro robot inside small pipe, the theoretical formula for velocity is obtained. This derived theoretical formula is demonstrated the feasibility through the comparison with experimental result. Also, we could find the most important element influencing the moving velocity of micro robot when the robot operates in small pipe. Consequently, it is expected that this study can supply useful information to design of crawling robot to move in small pipe.
A 3D FEA Model with Plastic Shots for Evaluation of Peening Residual Stress due to Multi-Impacts
Kim, Tae-Hyung ; Lee, Hyungy-Il ;
Transactions of the Korean Society of Mechanical Engineers A, volume 32, issue 8, 2008, Pages 642~653
DOI : 10.3795/KSME-A.2008.32.8.642
In this paper, we propose a 3-D finite element (FE) analysis model with combined physical behavior and kinematical impact factors for evaluation of residual stress in multi-impact shot peening. The FE model considers both physical behavior of material and characteristics of kinematical impact. The physical parameters include elastic-plastic FE modeling of shot ball, material damping coefficient, dynamic friction coefficient. The kinematical parameters include impact velocity and diameter of shot ball. Multi-impact FE model consists of 3-D symmetry-cell. We can describe a certain repeated area of peened specimen under equibiaxial residual stress by the cell. With the cell model, we investigate the FE peening coverage, dependency on the impact sequence, effect of repeated cycle. The proposed FE model provides converged and unique solution of surface stress, maximum compressive residual stress and deformation depth at four impact positions. Further, in contrast to the rigid and elastic shots, plastically deformable shot produces residual stresses closer to experimental solutions by X-ray diffraction. Consequently, it is confirmed that the FE model with peening factors and plastic shot is valid for multi-shot peening analyses.
Optimal Design of an MRI Device Considering the Homogeneity of the Magnetic Field
Lee, Jung-Hoon ; Yoo, Jeong-Hoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 32, issue 8, 2008, Pages 654~659
DOI : 10.3795/KSME-A.2008.32.8.654
This paper is to suggest a concept design of the permanent magnet type magnetic resonance imaging (MRI) device based on the parameter optimization method. Pulse currents in the gradient coils will introduce the effect of eddy currents in the ferromagnetic material, which will worsen the quality of imaging. In order to equalize the magnetic flux in the MRI device for good imaging, the eddy current effect in the ferromagnetic material must be taken into account. This study attempts to use the design of experiment (DOE) and the response surface method (RSM) for equalizing the magnetic flux of the permanent magnet type MRI device using that the magnetic flux can be calculated directly using a commercial finite element analysis package. As a result, optimal shapes of the pole and the yoke of the PM type MRI device can be obtained. The commercial package, ANSYS, is used for analyzing the magnetic field problem and obtaining the resultant magnetic flux.
Evaluation of Thermal Stratification and Primary Water Environment Effects on Fatigue Life of Austenitic Piping
Choi, Shin-Beom ; Woo, Seung-Wan ; Chang, Yoon-Suk ; Choi, Jae-Boong ; Kim, Young-Jin ; Lee, Jin-Ho ; Chung, Hae-Dong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 32, issue 8, 2008, Pages 660~667
DOI : 10.3795/KSME-A.2008.32.8.660
During the last two decades, lots of efforts have been devoted to resolve thermal stratification phenomenon and primary water environment issues. While several effective methods were proposed especially in related to thermally stratified flow analyses and corrosive material resistance experiments, however, lack of details on specific stress and fatigue evaluation make it difficult to quantify structural behaviors. In the present work, effects of the thermal stratification and primary water are numerically examined from a structural integrity point of view. First, a representative austenitic nuclear piping is selected and its stress components at critical locations are calculated in use of four stratified temperature inputs and eight transient conditions. Subsequently, both metal and environmental fatigue usage factors of the piping are determined by manipulating the stress components in accordance with NUREG/CR-5704 as well as ASME B&PV Codes. Key findings from the fatigue evaluation with applicability of pipe and three-dimensional solid finite elements are fully discussed and a recommendation for realistic evaluation is suggested.
Estimation of Residual Stress Distribution for Pressurizer Nozzle of Kori Nuclear Power Plant Considering Safe End
Song, Tae-Kwang ; Bae, Hong-Yeol ; Chun, Yun-Bae ; Oh, Chang-Young ; Kim, Yun-Jae ; Lee, Kyoung-Soo ; Park, Chi-Yong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 32, issue 8, 2008, Pages 668~677
DOI : 10.3795/KSME-A.2008.32.8.668
In nuclear power plants, ferritic low alloy steel nozzle was connected with austenitic stainless steel piping system through alloy 82/182 butt weld. Accurate estimation of residual stress for weldment is important in the sense that alloy 82/182 is susceptible to stress corrosion cracking. There are many results which predict residual stress distribution for alloy 82/182 weld between nozzle and pipe. However, nozzle and piping system usually connected through safe end which has short length. In this paper, residual stress distribution for pressurizer nozzle of Kori nuclear power plant was predicted using FE analysis, which consideded safe end. As a result, existing residual stress profile was redistributed and residual stress of inner surface was decreased specially. It means that safe end should be considered to reduce conservatism when estimating the piping system.
An Optimization of Restoration Method at Class V Lesion of a Finite Element Tooth Model
Kim, Kwang-Hoon ; Woo, Sung-Gwan ; Son, Kwon ; Park, Jeong-Kil ;
Transactions of the Korean Society of Mechanical Engineers A, volume 32, issue 8, 2008, Pages 678~684
DOI : 10.3795/KSME-A.2008.32.8.678
A general treatment is to restore abfraction lesions with dental filler materials to reduce stress concentration. A material should be selected from various dental products based on long term experiences of dentist or personal preference concerning filler methods. A quantitative criterion is necessary to make an evaluation of the results as dentists decide treatment methods and dental materials relying on their clinical experiences. The purpose of this study is to find an optimal restoration method and material for noncarious cervical lesions using the finite element method. An objective function was defined to minimize the sum of tension or compression stress. Trial-and-error and approximation were used to find an optimal restoration method. An optimal solution was to fill TetricFlow inside the lesion and Z100 in the remaining region. The most desirable thickness ratio of the two filler materials was 0.125 with trial-and-error and it was similar to the results of approximation, 0.121 and 0.132.
Trajectory Control of Underwater Robot using Time Delay Control
Park, Joon-Young ; Cho, Byung-Hak ; Lee, Jae-Kyung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 32, issue 8, 2008, Pages 685~692
DOI : 10.3795/KSME-A.2008.32.8.685
In this paper, the trajectory control problem of an underwater robot is addressed. From the viewpoint of control engineering, trajectory control of the underwater robot is not an easy task due to its nonlinear dynamics, which includes various hydraulic forces such as buoyancy forces and hydrodynamic damping, the difference between the centers of buoyancy and gravity, and disturbances from a tether cable. To solve such problems, we applied Time Delay Control to the underwater robot. This control law has a very simple structure not requiring the nonlinear plant dynamics, and was proven to be highly robust against disturbances and uncertainties. We confirmed its effectiveness through experiments.
Optimal Design of the Flexure Mounts for Satellite Camera by Using Design of Experiments
Kim, Hyun-Jung ; Seo, Yu-Deok ; Youn, Sung-Kie ; Lee, Seung-Hoon ; Lee, Deog-Gyu ; Lee, Eung-Shik ;
Transactions of the Korean Society of Mechanical Engineers A, volume 32, issue 8, 2008, Pages 693~700
DOI : 10.3795/KSME-A.2008.32.8.693
The primary mirror system in a satellite camera is an opto-mechanically coupled system for a reason that optical and mechanical behaviors are intricately interactive. In order to enhance the opto-mechanical performance of the primary mirror system, opto-mechanical behaviors should be thoroughly investigated by using various analysis procedures such as elastic, thermo-elastic, optical and eigenvalue analysis. In this paper, optimal design of the bipod flexure mounts for high opto-mechanical performance is performed. Optomechanical performances considered in this paper are RMS wavefront error under the gravity and thermal loading conditions and 1st natural frequency of the mirror system. The procedures of the flexure mounts design based on design of experiments and statistics is as follows. The experiments for opto-mechanical analysis are constructed based on the tables of orthogonal arrays and analysis of each experiment is carried out. In order to deal with the multiple opto-mechanical properties, MADM (Multiple-attribute decision making) is employed. From the analysis results, the critical design variables of the flexure mounts which have dominant influences on opto-mechanical performance are determined through analysis of variance and F-test. The regression model in terms of the critical design variables is constructed based on the response surfaceanalysis. Then the critical design variables are optimized from the regression model by using SQP algorithm. Opto-mechanical performance of the optimal bipod flexure mounts is verified through analysis.
A Study on the Development of the Continuous 3D Tube Bending Machine
Mun, Hyeon-Jun ; Kim, Chung-Sup ; Kim, Jong-Doo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 32, issue 8, 2008, Pages 701~706
DOI : 10.3795/KSME-A.2008.32.8.701
A continuous 3D tube bending machine has been developed for industrial boiler panel production. The machine consists of a main bender, a sub bender, a side bender, tube feeding rollers and control system that includes data management system. Tube position is controlled by a numerical control system. The bending former can be easily replaced according to the shape of bending form. Reduction of working time and improvement of production capacity from the practice have been achieved by bending a long tube in the machine developed.