• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.29 no.4 s.235
• /
• pp.614-623
• /
• 2005

This study aims to perform the characteristic evaluation of surface grinding for the STD11 material with experimental and analytic techniques based on the response surface model. The grinding force acting on the workpiece and the ground surface roughness were measured according to the change of grain size, table speed and depth of cut. The effect of spark-out on the grinding force and the surface roughness was also characterized. The frictional coefficient between workpiece and grinding wheel could be determined by the analysis of spark-out effect. From the experimental data, the second-order response surface models were developed to predict the grinding force and the surface roughness. Validation of the developed model was examined.

• Journal of Distribution Science
• /
• v.12 no.5
• /
• pp.93-107
• /
• 2014

Purpose - The pool of entrepreneurs with progressive qualities such as creativity and innovation was considered concurrently with such factors as work and capital that stimulate economic development and growth. This study aims to present a model to support the development of a strategic approach for achieving an overall academic entrepreneurship system in Iran. Research design, data, and methodology - The research design of this study is based on applied research because of its objectives, using principles and techniques formulated for basic research to solve operational and real organizational issues. This design also drives the method used, describing and interpreting the findings. Secondary data (library research) was used for this study's data collection. Because of this research's essential characteristics, no hypothesis is launched, and no research setting, questionnaire design, population or population sampling, validity or reliability tests, or statistical analysis are needed. Results and Conclusions - The model is created using a strategic approach acting in an octal setting comprising social, cultural, legal, economic, political, technological, competitive, and natural environments to present a conceptual framework for future studies.

• Proceedings of the KIEE Conference
• /
• 2002.04a
• /
• pp.12-14
• /
• 2002

In this paper, magnetic force on acting arc was analyzed by 3-D FEM for three DC arc-quenching rooms having different magnetic flux paths. We measured arc breaking time in prototypes by experiment so that we compared the relation of magnetic force and arc breaking time. Finally, we present the techniques for magnetically-driven arc and for the prediction of arc breaking time.

• Journal of Power System Engineering
• /
• v.5 no.1
• /
• pp.104-109
• /
• 2001

The stress distributions of hydranlic actuator cylinder tube acting in uniform inner pressure were analysed by the boundary element method(BEM). STKM13C tube was utilized for machine structural purposes model, its inner radius was 100 mm and outer radius was 140 mm. Axial length was semi-infinite and the isoparametric element of BEM was used. Radial and tangential stresses are maximum(-20.3 MPa and 52 MPa) at the inner radius and the minimum at the outer radius of the hydraulic actuator cylinders for an industrial systems. Stress diminution ratio was about 0.6 MPa/mm. And then coincidence between the simulation techniques as exact results(Lame' equation) and finite element method(FEM) is found to be fairly good, showing that the proposed analysis by BEM is reliable.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.05c
• /
• pp.51-54
• /
• 2001

This Paper is described basic principles of arc quenching in Molded Case Circuit Breaker. We analyzed magnetic blowout forces acting on the arc in contact system when circuit breakers interrupt fault currents in different three models by 3-D FEM(Finite Element Method). The interrupting time simulated is compared with that of short circuit tests. The results of this study derive valid of the simulation method and present the techniques to improve arc quenching performance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.05a
• /
• pp.917-920
• /
• 2003

The sloshing phenomenon sometimes happens to occur in a liquid fuel tank due to the unexpected and/or inevitable vibrating conditions and may result in severe effects on the structural stability. This study deals with the development of experimental techniques for the evaluation of sloshing behaviors in the liquid fuel tank and for the identification of natural frequencies and mode shapes by varying with various vibrating conditions. Measurements of the pressure and load acting on the side surface of vibrated liquid fuel tank are carried in order to identify the effects of sloshing phenomenon by using various types of baffles. The results show that the baffles can be used to minimize the sloshing phenomenon in liquid fuel tank effectively

• Wind and Structures
• /
• v.15 no.5
• /
• pp.441-462
• /
• 2012

This article presents theoretical investigations on techniques for the improvement of the dynamic characteristics of slender bridges under wind action. Aerodynamically effective control shields are applied as controlled actuators. The first part of the article describes the modelling of the uncontrolled aeroelastic system. Acting aerodynamic forces are consistently characterised using linear time-invariant transfer elements in terms of rational functions. On this basis, two configuration levels of the uncontrolled system are represented with linear time-invariant state-space models and investigated. The second part of the article addresses controller design and the behaviour of the controlled aeroelastic system. Both fundamental limits for stabilisation and the efficiency for attenuating the influence of gusts are described for different actuator mechanisms. The results are derived and discussed with methods of control theory.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.13 no.6
• /
• pp.15-22
• /
• 2014

With a conventional positioning apparatus, it is very difficult simultaneously to achieve desired driving ranges and precision levels at the sub-micrometer level. Generally, a lead screw and friction drive have been used as servo control systems. These have large driving ranges, and high-speed positioning is feasible. In this study, we present a global servo system controlled by a laser interferometer acting as a displacement measurement sensor for achieving positioning accuracy at the sub-micrometer level.

• Journal of the Korean Chemical Society
• /
• v.57 no.1
• /
• pp.52-62
• /
• 2013

The interaction of titanium (IV), yttrium (III), zirconium (IV), palladium (II) and cerium (IV) with deprotonated enrofloxacin leads to the formation of the neutral or cationic mononuclear complexes. The isolated solid complexes have been characterized with physicochemical and spectroscopic techniques and thermogravimeteric analyses. The spectroscopic data indicate that the enrofloxacin ligand is on the deprotonated mode acting as bidentate ligand coordinated to the metal ions through the ketone oxygen and a carboxylato oxygen and the metal ions completed the coordination number with water molecules. The thermal decomposition mechanisms proposed for enrofloxacin and their metal complexes were discussed. The activation energies, $E^*$, enthalpies, ${\Delta}H^*$, entropies, ${\Delta}S^*$ and Gibbs free energies, ${\Delta}G^*$, of the thermal decomposition reactions have been derived from thermogravimetric (TG) and differential thermogravimetric (DTG) curves, using Coats-Redfern (CR) and Horowitz-Metzeger (HM) methods. The antimicrobial activity has been evaluated against six different microorganisms.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.13 no.4
• /
• pp.764-770
• /
• 1989

This paper analyze the steady state performance of a self-acting air lubricated slider bearing in hard disk/head system. Modified Reynolds' equation is derived from the steady state compressible Navier-Stokes equation, under slip-flow conditions. Finite difference technique and numerical procedure are described by using Newton-Raphson iteration method to slove the non-linear equations. These techniques are applied to conventional slider bearings and the effects of molecular mean free path(MMFP) for a recording surface of hard disk are shown. The calculation procedure developed here, wide applicabilities in practical head design procedures, and converges rapidly.