• Journal of applied mathematics & informatics
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• v.34 no.5_6
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• pp.359-367
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• 2016

This paper deals with the Cauchy problem for heat equations with coupling moving reactions of mixed type. After obtaining the infinite Fujita blow-up exponent, we classify optimally the simultaneous and non-simultaneous blow-up for two components of the solutions. Moreover, blow-up rates and set are determined. By using the analogous procedures, one can fill in the gaps for the other two systems, which are studied in the paper 'Australian and New Zealand Industrial and Applied Mathematics Journal' 48(2006)37-56.

• Proceedings of the KAIS Fall Conference
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• 2011.05b
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• pp.529-532
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• 2011

A theoretical model has been studied to describe the sound radiation analysis for structure vibration noise of vehicle tires under the action of random moving line forces. When a tire is analyzed, it had been modeled as curved beams with distributed springs and dash pots that represent the radial, tangential stiffness and damping of tire, respectively. The reaction due to fluid loading on the vibratory response of the curved beam is taken into account. The curved beam is assumed to occupy the plane y=0 and to be axially infinite. The expression for sound power is integrated numerically and the results examined as a function of Mach number, wave-number ratio and stiffness factor. The experimental investigation for structure vibration noise of vehicle tire under the action of random moving line forces has been made. Based on the Spatial Transformation of Sound Field techniques, the sound power and sound radiation are measured. Results strongly suggest that operation condition in the tire material properties and design factors of the tire govern the sound power and sound radiation characteristics.

• Journal of Power System Engineering
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• v.7 no.3
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• pp.54-60
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• 2003

In general, the swing motion of the crane is controlled and suppressed by activating the trolley motion. In this paper, we suggest a new type of anti-sway control system of the crane. In the proposed control system, a small auxiliary mass(moving-mass) is installed on the spreader and the swing motion is controlled by moving the auxiliary mass. The actuator reaction against the auxiliary mass applies inertial control forces to the container to reduce the swing motion in the desired manner. In this paper, we apply the $H_{\infty}$ based control technique to the anti-sway control system design problem. And the experimental result shows that the proposed control system is shown to be useful and robust to disturbances like winds and initial sway motion.

• Journal of Power System Engineering
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• v.8 no.1
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• pp.55-61
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• 2004

In general, the swing motion of the crane is controlled and suppressed by activating the trolley motion. In this paper, we suggest a new type of anti-sway control system of the crane. In the proposed control system, a small auxiliary mass(moving-mass) is installed on the spreader and the swing motion is controlled by moving the auxiliary mass. The actuator reaction against the auxiliary mass applies inertial control forces to the container in order to reduce the swing motion in the desired manner. In this paper, we apply the $H_{\infty}$ based control technique to the anti-sway control system design problem. And the experimental result shows that the proposed control system is useful and robust to disturbances like winds and initial sway motion.

• Geomechanics and Engineering
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• v.28 no.1
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• pp.89-105
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• 2022

The behavior of the soil subgrade is complex and irregular against loads. When modeling, the soil is often replaced by a more straightforward system called a subgrade model. The Winkler method of linear elastic springs is a popular method of soil modeling in which the spring constant shows the modulus of subgrade reaction. In this research, the factors affecting the distribution of the modulus of subgrade reaction of elastoplastic subgrades are examined. For this purpose, critical theories about the modulus of subgrade reaction were examined. A square raft foundation on a sandy soil subgrade with was analyzed at different internal friction angles and Young's modulus values using ABAQUS software. To accurately model the actual soil behavior, the elastic, perfectly plastic constitutive model was applied to investigate a foundation on discrete springs. In order to increase the accuracy of soil modeling, equations have been proposed for the distribution of the subgrade reaction modulus. The constitutive model of the springs is elastic, perfectly plastic. It was observed that the modulus of subgrade reaction under an elastic load decreased when moving from the corner to the center of the foundation. For the ultimate load, the modulus of subgrade reaction increased as it moved from the corner to the center of the foundation.

• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.715-721
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• 2005

The SMB chromatography is used to obtain high purification of fructooligosaccharides (FOS), the mixture of kestose and nystose. SMB operation condition is usually determined by triangle theory or standing wave design when reactions do not occur within columns during experiment. Some of the reactions in columns may considerably affect experimental results. FOS can be hydrolyzed and converted into glucose and fructose during operation. To include the effect of reaction, the concentrations of each component at steady state after hydrolysis were used in simulation. The obtained simulation values are well matched with experimental results except sucrose. For sucrose, the experimental results were different from expected one due to the existence of an intermediate component. FOS is easily hydrolyzed and converted into glucose and fructose in more acidic condition and at higher temperature. Hydrolysis reaction can be prevented by the pretreatment of separation resin with NaOH as well as operation under lower temperature.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.11
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• pp.1138-1144
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• 2011

This article deals with the problem of fault detection of a spacecraft's actuators. The authors introduce an extended unknown input observer for nonlinear systems. This is an extended form of unknown input observers which are used for linear systems. Since faults are not available, those are considered as unknown inputs. Unknown input observers can estimate states without full information of inputs if some conditions are satisfied. The authors suggest a continuous-time extended UIO (eUIO) and prove the convergence of state estimation errors. Since the dynamic equation of a spacecraft is nonlinear, an extended UIO can be applied. Three eUIOs are designed to monitor three reaction wheels. The moving averages of each eUIO's residuals are selected for decision logic. The proposed method is verified by numerical simulations.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.914-917
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• 2002

Fabrication of micro carbon structures and patterns using laser-assisted chemical vapor deposition is studied. Argon ion laser and ethylene were used to grow micro carbon rod through pyrolytic decomposition of the reaction gas. The influence of reaction gas pressure and incident laser power on the diameter and growth rate of the micro carbon rod was experimentally investigated. The diameter of micro carbon rods increases linearly with respect to the laser power but is almost independent of the reaction gas pressure. Growth rate of the rod changes little with gas pressure when the laser power remains below 1W. When the carbon rod was grown at near threshold laser power, a very smooth surface is obtained on the rod. By continuously moving the focusing lens in the direction of growth, a micro carbon rod with a diameter of 28 ${\mu}{\textrm}{m}$ and aspect ratio of 100 was fabricated.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.3
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• pp.37-43
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• 2014

Kinetics of holocellulose hydrolysis in concentrated sulfuric acid was analyzed using $^1H$-NMR spectroscopy with different reaction time, temperature and acid concentration in secondary hydrolysis. In this work, reaction condition of secondary hydrolysis was similar to concentrated sulfuric acid process with electrodialysis or simulated moving bed chromatography process for sulfuric acid recycling. By $^1H$-NMR spectroscopy, acid hydrolyzates from higher secondary acid hydrolysis (25-35% acid concentration) was successfully analyzed without any difficulties in neutralization or adsorption of acid hydrolyzate to solid salt. Higher acid concentration, higher temperature and longer reaction time led to more cellulose for glucose conversion but accompanied with glucose to galactose isomerization, glucose to unknown compounds and degradation of glucose to organic acid via furans.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.65-72
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• 2016

This paper presents the analysis of the analysis of thrust characteristics of linear induction motors(LIMs) according to secondary reaction plate. LIMs are well known as high speed transport systems, which can obtain thrust directly without gears and links, or auxiliary mechanisms. A simple structure, easy maintenance, and less environmental pollution are advantages of LIMs. In transport systems using LIMs, the secondary reaction plate is an important design factor, because it has considerable impact on the cost of the railway as well as the performance of the LIMs. This paper deals analyzed the characteristics of linear induction motor used for moving the vehicle of container scanner. Thrust, efficiency and load characteristic were interpreted with FEM regarding two models whose material of secondary reaction plate was copper and aluminum. It suggested the interpretation of thrust, efficiency and power factor characteristic along slip and compared the operation ability of linear induction motor through characteristics analysis along the load.