• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4460-4473
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• 2022

The behaviour of the fission gas plays an important role in the fuel rod performance. In a previous work, we presented a physics-based model describing intra- and inter-granular behaviour of radioactive fission gas. The model was implemented in SCIANTIX, a mesoscale module for fission gas behaviour, and assessed against the CONTACT 1 irradiation experiment. In this work, we present the multi-scale coupling between the TRANSURANUS fuel performance code and SCIANTIX, used as mechanistic module for stable and radioactive fission gas behaviour. We exploit the coupled code version to reproduce two integral irradiation experiments involving standard fuel rod segments in steady-state operation (CONTACT 1) and during successive power transients (HATAC C2). The simulation results demonstrate the predictive capabilities of the code coupling and contribute to the integral validation of the models implemented in SCIANTIX.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.11
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• pp.18-28
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• 1999

A new equivalent circuit model of package (SOP, Small Outline Package) is presented for designing radio frequency integrated circuits (RFIC). In the RF region, the paddle of a package does not work as an ideal ground. Further parasitics due to both coupling and loss have a substantial effect on MMIC. The equivalent circuit model and parameter extraction methodology for the electrical characteristics of the package are described by illustrating the SOP type packages. The accuracy of the model is evaluated by comparing the s-parameters of the commercial full-wave solver and those of HSPICE simulation with the circuit model. The proposed model shows an excellent agreement with full-wave analysis up to about 8GHz.

• Coupled systems mechanics
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• v.9 no.2
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• pp.125-145
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• 2020

In this paper, we present a 3D thermo-hydro-mechanical coupled discrete beam lattice model of structure built of the nonisothermal saturated poro-plastic medium subjected to mechanical loads and nonstationary heat transfer conditions. The proposed model is based on Voronoi cell representation of the domain with cohesive links represented as inelastic Timoshenko beam finite elements enhanced with additional kinematics in terms of embedded strong discontinuities in axial and both transverse directions. The enhanced Timoshenko beam finite element is capable of modeling crack formation in mode I, mode II and mode III. Mode I relates to crack opening, mode II relates to in-plane crack sliding, and mode III relates to the out-of-plane shear sliding. The pore fluid flow and heat flow in the proposed model are governed by Darcy's law and Fourier's law for heat conduction, respectively. The pore pressure field and temperature field are approximated with linear tetrahedral finite elements. By exploiting nodal point quadrature rule for numerical integration on tetrahedral finite elements and duality property between Voronoi diagram and Delaunay tetrahedralization, the numerical implementation of the coupling results with additional pore pressure and temperature degrees of freedom placed at each node of a Timoshenko beam finite element. The results of several numerical simulations are presented and discussed.

• Journal of the Korean Vacuum Society
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• v.19 no.1
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• pp.72-80
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• 2010

It is very important to predict and analyze the change of voltage and current distribution of current strap, abnormal voltage distribution of transmission line and resonance phenomenon by coupling between current straps for more stable operation of ICRF system. In this study, to understand those phenomena by coupling, 8-port coupled transmission line model is completed by appling S-parameter measured in the prototype KSTAR ICRF antenna to the model. The determined self-inductance, mutual-inductance and capacitance of antenna straps are shown to be lower than that calculated from 2D approximate model due to finite length of strap. The coupled transmission line model of current strap will be utilized to the operation of ICRF system of KSTAR in the future.

• Journal of Drive and Control
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• v.21 no.2
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• pp.44-52
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• 2024

In this study, we predicted PTO power requirements based on torque predicted by the discrete element method and the multi-body dynamics coupling method. Six different scenarios were simulated to predict PTO power requirements in different soil conditions. The first scenario was a tillage operation on cohesionless soil, and the field was modeled using the Hertz-Mindlin contact model. In the second through sixth scenarios, tillage operations were performed on viscous soils, and the field was represented by the Hertz-Mindlin + JKR model for cohesion. To check the influence of surface energy, a parameter to reproduce cohesion, on the power requirement, a simple regression analysis was performed. The significance and appropriateness of the regression model were checked and found to be acceptable. The study findings are expected to be used in design optimization studies of agricultural machinery by predicting power requirements using the discrete element method and the multi-body dynamics coupling method and analyzing the effect of soil cohesion on the power requirement.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.8
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• pp.1480-1486
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• 2002

In this study, the cross-coupling control (CCC) with three new features is proposed to maintain contour precision in high-speed nonlinear contour machining. One is an improved contour error model that provides almost exact calculation of the errors. Another is the utilization of variable controller gains based on the instantaneous curvature of the contour and the variable command. For this scheme, a stability is analyzed. As a result, the stability region is obtained, and the variable gains are decided within that region. The other scheme in the proposed CCC is a real-time feedrate adaptation module to regulate cutting force fur better surface finish through regulation of material removal rate (MRR). The simulation results show that the proposed CCC system can provide better precision than the existing method particularly in high-speed machining of nonlinear contours.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.7
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• pp.1231-1235
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• 2007

This paper presents the dynamic characteristics of a linear brushless dc (BLDC) motor with permanent magnet excitation for the precision conveyor according to the load condition. Dynamic performance of the linear BLDC motor driven with 6 step inverter such as thrust force and speed is simulated by finite element method coupling with external circuit and measured for the prototype motor. The results of finite element analysis are compared to the experimental results and verify reliability.

• BMB Reports
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• v.51 no.6
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• pp.263-264
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• 2018

We identified osteoclast-derived SLIT3 as a new coupling factor using fractionated secretomics. Coupling links bone resorption to bone formation. SLIT3 stimulated the recruitment and proliferation of osteoblasts into bone remodeling sites via activation of ${\beta}-catenin$. Autocrine signaling by SLIT3 also inhibited bone resorption by suppressing the fusion and differentiation of pre-osteoclasts. All mice lacking Slit3 or its receptor Robo1 showed an osteopenic phenotype with low bone formation and high bone resorption. A small truncated recombinant SLIT3 protein increased bone mass in an osteopenic mouse model. These results suggest that SLIT3 is a novel therapeutic target in metabolic bone diseases.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1034-1039
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• 2000

In turbo-machines operated at high speeds through gear speed increasers a precise coupled analysis of lateral and torsional vibrations is required to achieve highly reliable designs with low vibration and low noise levels, where the vibration coupling is due to the gear pair mesh stiffness. In this paper, applying the generalized coupled lateral-torsional finite element model of a gear pair element, has been analyzed a coupled lateral-torsional vibration of the prototype 800 RT turbo-chiller rotor-bearing system with a bull-pinion gear speed increaser. Results have shown that the coupled torsional natural frequencies have decreased due to the coupling effect of lateral vibration and particularly, the 2nd torsional natural frequency and its mode shape have had big changes. However, changes of lateral vibration characteristics have been noticed only at high lateral whirl natural frequencies above 15,000 rpm.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.446-451
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• 2000

In this paper, a new adaptive cross-coupling control (CCC) algorithm with an improved contour error model is proposed to maintain contouring precision in high-speed nonlinear contour machining. The proposed method utilizes variable controller gains based on the instantaneous curvature of a contour and the feedrate command. The proposed method is evaluated and compared with the conventional CCC for nonlinear contouring motion through computer simulations. The simulation results show that the proposed CCC improves the contouring accuracy more effectively than the existing method.