• Transactions of the Korean Society of Automotive Engineers
• /
• v.5 no.2
• /
• pp.197-204
• /
• 1997

In order to investigate the relationship between the ring gap ratio and oil consumption, the axial motion of piston ring was measured by capacitance technique. The pressures of each land and the motions of each ring were calculated by orifice-volume method in which it is assumed that the ring gaps are the only gas leakage paths. The calculated results were compared with the measured ones. Consequently, it is known that the increase of ring gap ratio has the effect of lifting the first ring. The calculated results were roughly in accordance with those measured. Therefore, it is possible to predict the effect of design variables on the pattern of ring motion. It is known that the lift off of first ring accompanied by the increase of ring gap ratio make rise of oil consumption.

• Journal of Photoscience
• /
• v.5 no.1
• /
• pp.33-37
• /
• 1998

One macroscopic effect in the free-running Er:YAG laser is an accumulation of microscopic effects. Understanding of the exogenous water induced mechanical effect on the dental hard tissue by the Qswitched Er:YAG laser has an important impact on the further understanding of the free-running Er:YAG laser ablation on the dental hard tissue. The Q-switched Er:YAG laser (1-$\mu$s-long pulse width) was used in the recoil pressure measurement with an aid of water-jet system and a pressure transducer. The amplitude of the recoil pressure depends on the tooth surface conditions (dry and wet) and the volume of the water upon it. Wet surfaces yielded higher recoil pressure than that of dry, surface, and as the volume of the exogenous water drop increased, the amplitude of the recoil pressure increased also.

• Journal of the Korean Society for Heat Treatment
• /
• v.17 no.6
• /
• pp.342-345
• /
• 2004

In this work, a new method of measuring volume fraction of deformation-induced ${\varepsilon}$ martensite is proposed using endothermic heat on reverse transformation. As grain size increases, the amount of ${\varepsilon}$ martensite forming on cooling increases. However, with a decrease in grain size, more ${\varepsilon}$ is induced by deformation, improving shape memory effect.

• Korean Journal of Crystallography
• /
• v.11 no.3
• /
• pp.157-161
• /
• 2000

In a 200nm Cz-Si crystal, a macroscopic fluctuation in pulling rate was intentionally introduced an then the variations of the pulling rate and the position of OSF-ring were compared each other. The formation behavior of OSF-ring in the effective volume, defined as the region between the growth interface position -α and the growth interface position +α, is most affected by the pulling rate fluctuation. To understand the correct effect of a macroscopic pulling rate fluctuation, its cumulative effect in the effective volume should be considered. A new concept of modeling for it was proposed here.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.31 no.12
• /
• pp.1017-1023
• /
• 2007

This study is intended to analyze the effect of thin ink-film thickness around rotating printing roll on the printing quality in the gravure printing process which is used for making electronics circuit like a RFID tag with a conductive ink. The present work numerically estimates the film thickness around rotating roller partially immersed in ink for which the volume of fluid (VOF) method was adopted to figure out the film formation process around rotating roller. Parameter studies were performed to compare the effect of ink properties (viscosity, surface tension), operating condition (roller rotating speed, initial immersed angle) on the film thickness. The result indicates that the film thickness has a strong dependency on the rotating speed, while the surface tension has negligible effect.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.21 no.4
• /
• pp.225-244
• /
• 2017

The natural convective nanofluid flow and heat transfer inside a square enclosure with a center heater in the presence of magnetic field has been studied numerically. The vertical walls of the enclosure are cold and the top wall is adiabatic while the bottom wall is considered with constant heat source. The governing differential equations are solved by using a finite volume method based on SIMPLE algorithm. The parametric study is performed to analyze the effect of different lengths of center heater, Hartmann numbers and Rayleigh numbers. The heater effectiveness and temperature distribution are examined. The effect of all pertinent parameters on streamlines, isotherms, velocity profiles and average Nusselt numbers are presented. It is found that heat transfer increases with the increase of heater length, whereas it decreases with the increase of magnetic field effect. Furthermore, it is found that the value of Nusselt number depends strongly upon the Hartmann number for the increasing values of Rayleigh number.

• Nuclear Engineering and Technology
• /
• v.53 no.4
• /
• pp.1109-1118
• /
• 2021

The construction of STELLA-2 facility is on-going to demonstrate the safety system of PGSFR and to provide comprehensive understanding of transient behavior under DBEs. Considering that most events are single-phase natural circulation flow with slow transient, STELLA-2 was designed with reduced-height of 1/5 length scale. The ratio of volume to surface area in the vessel can relatively increase resulting in excessive heat transfer. Therefore, a steady-state thermal-hydraulic analysis was performed and the effect of design change to reduce the heat transfer through redan was investigated. The heat transfer through single wall redan in STELLA-2 was 3% of the core power, comparable to 1% of the core power in PGSFR. By applying the insulated redan, about 70% of decrease effect was observed. The effect on transient behavior was also evaluated. The conclusion of this study was directly applied to the STELLA-2 design and the modified version is under construction.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2021.05a
• /
• pp.72-73
• /
• 2021

For the development of high-fluidity concrete using low-binder, The effect of the use of the developed acrylic viscosity agent on the physical properties of concrete evaluated. The amount acrylic viscosity agent used was 1.5%, 1.7%, and 2.0% based on the binder amount of 400kg/m3, and slump flow test, slump flow 500mm arrival time measurement, air volume measurement, and U-Box passing test were conducted to determine the effect of the physical properties of concrete. it was judged that 1.5% of the acrylic viscosity agent used in high-fluidity concrete using low-binder was most suitable.

• The Journal of the Society of Stroke on Korean Medicine
• /
• v.7 no.1
• /
• pp.1-10
• /
• 2006

Objectives : Yanggyuksanhwa-tang is a prescription used for cerebral infarction clinically. Methods : According to previous research data, the effect of Yanggyuksanhwa-tang on cerebral infarction, we induced cerebral infarction by middle cerebral artery occlusion(MCAO) in rats, and the rats were administered Yanggyuksanhwa-tang. Results: Infarct area, infarct volume were measured, and the level of elements such as c-Fos, Bax and caspase-3 in penumbra of infarct were expressed by immunohistochemical staining. Conclusion : Yanggyuksanhwa-tang showed neuroprotective effect through preventing neuronal cell apoptosis.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2021.11a
• /
• pp.129-130
• /
• 2021

For the development of high-fluidity concrete using low-binder, The effect of the use of the developed acrylic viscosity agent on the physical properties of concrete evaluated. The amount acrylic viscosity agent used was 0.28%, 0.29% and 0.30% based on the binder amount of 350kg/m³, and slump flow test, air volume measurement, U-Box passing test and strength compressive were conducted to determine the effect of the physical properties of concrete. it was judged that 0.29% of the cellulose type viscosity agent used in high-fluidity concrete using low-binder was most suitable.