• Journal of Energy Engineering
• /
• v.23 no.3
• /
• pp.191-197
• /
• 2014

To increase the heat transfer rate of the air pre-heating heat exchanger used for the condensing boiler, We investigated condensation heat transfer coefficients through plasma surface treatment. The hydrophilic surface showed about 10% increase in heat transfer rate than original plate. It shows that Shah correlation can be used to predict the condensation heat transfer coefficient on the original surface within 10% error range after the compatison between Shah correlation and the condensation heat transfer coefficients measured on the hydrophilic surface and original surface. Therefore, we have shown that Shah correlation is available when designing the air pre-heating heat exchanger using the original surface in this study.

• Journal of Environmental Science International
• /
• v.3 no.4
• /
• pp.305-315
• /
• 1994

The field observation was carried out to investigate the characteristics of surface inversion layer at Kimhae using the feild observed date and upper layer meteorological data during 4-5 February 1993. The results of the study can be summarized as follows : The maximum height of surface inversion layer observed at Kimhae is 193m and the height of upper level inversion layer ranges from 2nm to 300m. The surface weather elements was influenced the formation of surface inversion layer. According to the pasquill stability and time variation of temperature with height, both the surface heating from insolation and the disturbance of upper level of inversion layer was influenced the disappearance of inversion layer. And the stability of surface temperature inversion layer generally belongs to the class of F, that of upper level temperature inversion layer commonly to the class of E.

• Aerospace Engineering and Technology
• /
• v.9 no.1
• /
• pp.35-41
• /
• 2010

The temperature of the flight objects in high speed increases due to the aerodynamic heating. MINIVER and CFD approach are used to predict the aerodynamic heating conditions of KSLV-I. MINIVER is based on the empirical method. And the CFD approach predicts the aerodynamic heating conditions after the analysis of the surface temperature and the surface heat flux directly. In this study, the aerodynamic heating conditions using CFD approach are considered. The PLF temperature for these aerodynamic heating conditions is compared with the flight test data of KSLV-I.

• Journal of the Society of Naval Architects of Korea
• /
• v.31 no.4
• /
• pp.139-146
• /
• 1994

In this paper a feasible way toward the automation for plate forming by line heating method is proposed. For this a mechanical model representing the line heating phenomenon is adopted and a reasonable algorithm is introduced to search the heating path under the given heating conditions, which can produce the surface very similar to the given surface. A computer program system has been developed according to the proposed algorithm here. It has been applied to two curved shapes to show its validity. From the results it has been found that the proposed algorithm and the developed computer program system give a good result and can be a possible way getting to the automation system of plate forming by the line heating method.

• Nuclear Engineering and Technology
• /
• v.54 no.2
• /
• pp.469-478
• /
• 2022

Tritium was extracted from tritium-contaminated aluminum samples by heating it in a high-temperature furnace at 200, 300, or 400 ℃ for 15 h. The extracted tritium was analyzed by using a liquid scintillation counter (LSC); the sample thicknesses were 0.4 and 2 mm. The differences in tritium extraction over time were also investigated by cutting aluminum stick samples into several pieces (1, 5, 10, and 15) with the same thickness, and subsequently heating them. The results revealed that there are most of the hydrated material based on tritium on the surface of aluminum. When the temperature was increased from 200 or 300 ℃-400 ℃, there are no large differences in the heating duration required for the radioactivity concentration to be lower than the MDA value. Additionally, at the same thickness, because the surface of aluminum is only contaminated to tritiated water, cutting the aluminum samples into several pieces (5, 10, and 15) did not have a substantial effect on the tritium extraction fraction at any of the applied heating temperatures (200, 300, or 400 ℃). The proportion of each tritium-release materials (aluminum hydrate based on tritium) were investigated via diverse analyses (LSC, XRD, and SEM-EDS).

• Journal of Marine Bioscience and Biotechnology
• /
• v.16 no.1
• /
• pp.19-25
• /
• 2024

To verify the color change in dried laver postproduction during the heating process, chromaticity elements were compared via a spectrophotometer across various heating conditions within the visible light spectrum. In general, the moisture reduction rate increased with rising temperature and time. Surface image comparisons revealed an expanded area of light reflection on the heat-treated dried laver sample due to surface roughening from shrinkage. No statistically significant differences in chromaticity values were observed in the measurements of brightness (L^*), redness (a^*), and yellowness (b^*). Reflectance spectrum measurements in the visible light region confirmed high reflectance under red wavelength conditions. In particular, a significant increase in reflectance at 700 nm compared with untreated samples was noted. The correlation between the increase in 700 nm reflectance of dried laver samples and heating conditions ranged from 0.7471 to 0.7793, suggesting its potential use as an indicator for comparing color changes in dried laver based on heating conditions.

• Transactions of Materials Processing
• /
• v.14 no.3 s.75
• /
• pp.263-268
• /
• 2005

Heating channel layout design and evaluation technology for SMC molding system was investigated in this work. Traditional rules of cooling channel design in injection molding were applied to the present work. Finite element thermal analysis with $ANSYS^{TM}$ was performed to evaluate the temperature distribution of SHC mold surface. SMC mold was manufactured to evaluate the effect of a proposed heating channel layout system on the temperature distribution of SMC mold surface and infrared camera was applied to a measurement of temperature distribution. It was shown that infrared camera application was possible in a measurement of temperature distribution on SHC mold surface.

• Proceedings of the KWS Conference
• /
• 2003.05a
• /
• pp.114-116
• /
• 2003

The multi function sprayed coating is used for direct-heating, wear resistance and high bonding strength. The merits of surface direct-heating coatings are short warming time, low power consumption and better wear resistance that can be used in many organization parts. In this study, the surface direct-heating and wear resistance can be improved by spraying the proper materials on the surface $Al_2$O$_3$40%TiO$_2$ powder and Ni-20%Cr powder that had the properties of conduction and high wear resistivity are used in order to improve wear resistance, electrical properties and bonding strength.

• KSBB Journal
• /
• v.6 no.4
• /
• pp.425-429
• /
• 1991

Porous glasses were prepared from $TiO_2$ containing borosilicate glass by the phase separation. Pore distribution and surface area of porous glasses were invesigated by SEM and porosimeter. As temperature and heating time increase. The pore size and volume increased, but the specific surface area decreased above the critical temperature. The specific surface area and pore size showed more sensitive change on the variation of heating temperature than of heating time.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.05a
• /
• pp.243-248
• /
• 2001

The objective of this study is to investigate the thermal conductivity of cement mortar for apartment housing floor using expansive admixture, copper fiber, cower lathe, hollowed aluminum plate. According to test results, temperature at point (a) located above heating pipe does not show significant variation with age, and temperature at (b), which is located at the finishing surface above heating pipe, and temperature at (c), which is located at center surface between heating pipe has remarkable change. Temperature distribution sat (b) are in order for, structure containing copper fiber>plain structure>structure containing hollowed aluminum plate>structure containing expansive admixture. Temperature distribution, shows high tendency in order for, structure containing copper fiber>structure containing copper lathe>structure containing hollowed aluminum plate>plain structure>structure containing expansive admixture. (a) estimation of temperature distribution is determined with the variation of temperature between (b) point and (c) point during 60 minutes heating.