• Proceedings of the Korean Vacuum Society Conference
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• 2009.02a
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• pp.217.2-217.2
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• 2009

• Proceedings of the Korean Fiber Society Conference
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• 2001.04a
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• pp.359.1-360
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• 2001

• Tunnel and Underground Space
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• v.17 no.6
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• pp.464-474
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• 2007

An enhancement in the performance and safety of a high-level waste repository requires a validation of its engineered barrier. An engineering-scale test (named "KENTEX") has been conducted to investigate the thermal-hydro-mechanical behaviors in the engineered barrier of the Korean reference disposal system The validation test started on May 31, 2005 and is still under operation. The experimental data obtained allowed a preliminary and qualitative interpretation of the thermal-hydro-mechanical behaviors in the bentonite blocks. The temperature was higher as it became closer to the heater, while it became lower as it was farther away from the heater. The water content had a higher value in the part close to the hydration surface than that in the heater part. The relative humidity data suggested that a hydration of the bentonite blocks might occur by different drying-wetting processes, depending on their position. The total pressure was continuously increased by the evolution of the saturation front in the bentonite blocks and thereby the swelling pressure. Near the heater region, there was also a significant contribution of the thermal expansion of bentonite and the vapor pressure in the pores of the bentonite blocks.

• Journal of the Korean Society for Heat Treatment
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• v.7 no.3
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• pp.169-174
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• 1994

The reaction layer formed at interface between matrix and fiber has significant effects on the mechanical properties and behaviors of deformation m FRM. In this study, the mechanical properties and interfacial behaviors according to surface finishing on the fibers and according to heat treatment in FRM were investigated. FRM was fibricated by diffusion bonding method. In W/Al alloy composite and W/Al composite, W of which was coated with $WO_3$, the heat treatment was carried out thermal cycling method from 373K to 673K. In W/Al composite, W of which was coated with $WO_3$, growth of interface layer was hardly occured in spite of the increasing various thermal cycles. It was exhibited that oxidized W/Al composite were higher strength than non-oxidezed W/Al composite with the increasing thermal cycles. The compounds of fiber/matrix interface were analyzed into $WAl_{12}$, $WAl_7$, and $AlWO_3$, respectivly. Therefore the interfacial compounds of fiber/matrix seriously affected the mechanical properties and behaviors of deformation in FRM.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.252-261
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• 1999

The troubles such as slipping, pinching and other behaviors in the service of cold rolling mills often induce thermal shock crack on the surface of work roll, and considerably reduce their service lives. In order to evaluate thermal shock resistibility we use thermal shock tester generating frictional heat caused by a rotating disc contacting with test specimens. Thermal shock produces two heat affected layers below the roll surface, one is rehardened layer and the other is succeeding tempered layer. The maximum depth of crack occurred in a thermal shocked area is a criterion for the thermal shock resistibility. This paper describes on the investigation to the influence of hardness and residual stress.

• Applied Chemistry for Engineering
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• v.25 no.5
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• pp.463-467
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• 2014

In this paper, the thermal behaviors of expanded graphite(EG)/erythritol composites with different contents of EG were studied. The surface and structure properties of the composites were determined by using scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD), respectively. The thermal properties were investigated by differential scanning calorimetry (DSC) and thermal conductivity (TC). As experimental results, the thermal conductivity of the composites increased with increasing the EG content. However, the latent heat was somewhat decreased in the presence of EG. We could concluded that EG was highly promising materials for improving the heat transfer enhancement and energy storage capacity of phase change materials (PCMs).

• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.287-292
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• 2019

This paper analyzes the thermal behaviors of genuine discs used in automobiles and discs coming out of tuning products through FEM analysis. Modeling with genuine disk modeling and tuning disks Model-1, Model-2, Model-3 and analyzing the disk rotation speed was set to 1000rpm. When the brake is operated, the thermal behavior of the disk surface, such as the operating temperature caused by the disk and pad contact, the friction surface temperature after the disk stop, and the thermal deformation, were analyzed. When the brake was activated (0-4.5 seconds), the tuning disk showed 34℃ higher than the original disk, and after the disk stopped (40.5 seconds), the tuning disk was analyzed 18℃ lowe, deformation due to the disk heat was deformed by 0.3mm for the tuning disk. Although there is an effect to reduce the fading phenomenon due to the thermal behavior of the pure disk and the tuning disk, it can be observed that there is no significant change in the thermal behavior due to the hole processing and the disk surface processing of the tuning disk.

• Polymer(Korea)
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• v.25 no.2
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• pp.168-176
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• 2001

The effect of novel N-crotyl-N,N-dimethyl-4-methylanilinium hexafluoroantimonate (CMH) curing agent as a thermal latent initiator on thermal behaviors, rheological properties, and thermal stability of diglycidylether of bisphenol A (DGEBA) epoxy cationic system was investigated. From DSC measurements of DGEBA/CMH system, it was shown that this system exhibits an excellent thermal latent characteristic at a given temperature. The conversion and conversion rate of DGEBA/CMH system increased with increasing the concentration of initiator, due to high activity of CMH. Rheological properties of the system were investigated under isothermal condition using a rheometer The gelation time was obtained from the analysis of storage modulus (G'), loss modulus (G"), and damping factor (tan $\delta$). As a result, the reduction of gelation time was affected by high curing temperature and concentration of CMH, resulting in high degree of network formation in cationic polymerization, due to difference of activity. The thermal stability of the cured epoxy resin was discussed in terms of the activation energy for decomposition and thermal factors determined from TGA measurements.ents.

• Journal of the Korean Ceramic Society
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• v.55 no.5
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• pp.452-460
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• 2018

This study investigate changes in mechanical behaviors such as indentation load-displacement and hardness of thermal barrier coatings (TBCs) using cycling of thermal shock test. Relatively dense and porous TBCs on nickel-based bondcoat/super alloy are prepared using different starting granules, 204C-NS and 204NS commercial powers, and the effect of double layers of 204C-NS on 204NS and 204NS on 204C-NS are investigated. The highest temperature applied during thermal shock test is $1100^{\circ}C$ and the maximum number of cycles is 1,200. The results indicate that bilayered TBC showed a relatively mechanically resistant property during thermal shock cycles and that the mechanical behavior is influenced by the microstructure of TBCs by exposure to high temperature during tests or different starting granules.

• Advances in nano research
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• v.10 no.1
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• pp.1-14
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• 2021

In the present computational approach, thermal buckling and frequency characteristics of a doubly curved laminated nanopanel with the aid of Two-Dimensional Generalized Differential Quadrature Method (2D-GDQM) and Nonlocal Strain Gradient Theory (NSGT) are investigated. Additionally, the temperature changes along the thickness direction nonlinearly. The novelty of the current study is in considering the effects of laminated composite and thermal in addition of size effect on frequency, thermal buckling, and dynamic deflections of the laminated nanopanel. The acquired numerical and analytical results are compared by each other to validate the results. The results demonstrate that some geometrical and physical parameters, have noticeable effects on the frequency and pre-thermal buckling behavior of the doubly curved open cylindrical laminated nanopanel. The favorable suggestion of this survey is that for designing the laminated nano-sized structure should pay special attention to size-dependent parameters because nonlocal and length scale parameters have an important role in the static and dynamic behaviors of the laminated nanopanel.