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

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.3 s.55
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• pp.127-134
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• 2009

This study investigated their properties of spalling resistance and residual compressive strength after fire test corresponding to various ISO, RABT heating curves, and contents of hybrid organic fiber of high strength concrete. The results were summarized as following. As fundamental characters of concrete with hybrid organic fiber, the flowability was directly declined as the increase of fiber contents, and air contents were decreased or increased a little bit, but there was not big difference. The compressive strength was gradually declined sluggishly at 28 days. As properties of fire resistance, in case of RABT heating curves, compare with ISO heating curves a spalling aspect showed till range that has much contents of hybrid organic fiber, but they are mostly peeling spalling, which means spalling aspect didn't happen to inside. In conclusion, in case of W/B 25% high strength concrete, the spalling was prevented over 0.04% of contents of fiber at ISO heating curve and over 0.10% of contents of fiber at the RABT heating curve. In case of spalling was prevented, mass reduction rate according to the change of heating temperature curves showed around 7% at ISO heating curves and around 9% at RABT heating curves. The residual compressive strength rate corresponding to the change of heating temperature curves showed 50%~60% at ISO heating temperature curves and 30%~35% at RABT heating temperature curves in case of spalling was prevented.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.169.2-169.2
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• 2010

The research assesses the performance of the water-to-water heat pump system installed in Cheongju water treatment plant for cooling and heating ventilation. In summer season monthly averaged COP is ranged from 3.85 to 4.56 according to the water source temperature, and the performance is increased as the raw water temperature is dropped. While, heating performance is increased for the high temperature water source, and the monthly averaged COP is changed from 2.92 to 3.82. The correlation of the water source temperature and the heat pump performance shows a linear tendency by the simple regression of average data. In heating, the COP of heat pump system linearly rises according to the water source temperature. In comparison, the COP in cooling linearly reduces as the raw water temperature is raised. The goodness of fit at the simple regression shows the coefficient of determination 82% in cooling, 46% in heating. The electric cost of water-to-water heat pump is reduced by 40% compared to that of air source heat pump.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.10
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• pp.677-682
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• 2017

Lamination is used extensively in various industries. The type of lamination applied to the material depends on the precision level required, which varies for materials needed for everyday use, materials used in high-tech industries, and processes employed to fabricate finished products. Especially in hot lamination, the distribution of the surface temperature of the heating roller is very important to avoid the generation of internal bubbles and ensure flatness of the attached materials, and thus maintain a good standard of quality and productivity. In this study, we have developed a system to monitor the surface temperature of the heating rollerby applying a heterogeneous controller and a non - contact temperature sensor. This monitoring system accurately measures the surface temperature of the heating roller and applies the RS485 MODBUS communication method for easy expansion. Using this system, a laminated prototype was fabricated, and its efficacy for non-contact temperature sensor calibration, Ethernet IP communication, stoppage of the heating roller, and determination of temperature distribution with rotation was examined for its potential usage in industries.

• Culinary science and hospitality research
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• v.14 no.3
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• pp.210-222
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• 2008

This study showed that the brown stock, which is the base of demi-glace sauce, extracted by using a high pressure heating extractor is more advantageous than that extracted by the traditional extraction method for the mass production. We compared the former with the latter in terms of minerals and free amino acids. The results of this study are summarized as follows. When mineral contents were compared, the brown stock extracted by high.pressure heating extraction showed the tendency of increase in mineral contents in proportion to heating temperature and heating time, but, from extraction temperature of 140$^{\circ}C$, the contents of K, Mg, Na and P decreased with the increase of extraction time. In addition, mineral contents in the brown stock extracted by high-pressure heating extraction were generally lower than those in brown stock extracted by the traditional extraction method. This result was produced probably because materials were added repeatedly in the traditional method. Amino acids contents in brown stock according to the extraction methods were also examined. They increased with the increase in the number of extractions in the brown stock extracted by the traditional method, and those in the brown stock extracted using a high pressure heating extractor increased with the increase in heating temperature and extraction time. The results of this study are expected to be useful as a practical material for the mass production of brown stock products.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.2
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• pp.173-181
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• 1994

A Cold spot temperature control system for the batch annealing furnace has been estabilished in order to reduce energy consumption to improve productivity and stabilize the propertics of products. Therefore we confirmed a relation between annealing cycle time and atmospheric gas, variation of coil cold spot temperature with time during heating and actual temperature measurements at mid-width of each coil during heating and actual temperature measurements at mid-width of each coil during soaking. The results of the tempaeature variation effect on the batch annealing are as follows. 1) Heating time is reduced to one half with increasing atmospheric gas flow rate and changing of atmospheric gas component from HNx to Ax gas, and annealing cycle time is reduced to 2.7 times. 2) In case of short time healing, the slowest heating part is the center of B coil, in case of long time heating, the low temperature point moves from the center of coil to inside coil. And the temperature in this part is higher than other parts when cooling. When finished heating, the cold spot is located 1/3 of coil inside in case of HNx atmospheric gas. But center of coil in case of Ax atmospheric gas. 3) The outside of top coil is the highest temperature point when heating, which becomes the lowest temperature point when cooling. So, this point becomes high temperature zone at heating and low temperature zone at cooling, It has relation according to atmospheric gas component and flow rate. 4) Soaking time at batch annealing cycle determination is made a decision by the input coil width, and soaking time for quality homogenization of 1214mm width coil must be 2.5 hours longer than that of 914mm width coil for the same ciol weight. 5) Annealing cycle time with Ax atmospheric gas is extended 1 hour in of slow cooling during 5 hours in order to avoid rapid cooling.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.146-147
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• 2021

In this study, the deterioration of concrete subjected to high temperature was evaluated using harmonics. When concrete is exposed to high temperatures, its mechanical properties deteriorate. In order to evaluate this deterioration, a method of analyzing the waveform of elastic waves was applied. As the heating temperature increased, the fundamental wave of the 50 kHz elastic wave passing through the concrete decreased. In addition, harmonics were generated at each temperature, and the higher the heating temperature, the greater the ratio of harmonics. The higher the compressive strength, the greater the amplitude of the fundamental wave, and this phenomenon is thought to be due to the internal structure of concrete.

• Journal of the Korean Ceramic Society
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• v.49 no.1
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• pp.124-129
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• 2012

An M-shaped SiC gas igniter was fabricated by a reaction sintering followed by nitrogen doping. The igniter showed both resistivity at room temperature and NTC to PTC transition temperature values that were lower than those of commercial igniters. It was deduced that the doped nitrogen reduces the electrical resistivity at room temperature, while, at high temperature, the doped nitrogen and a trace of $Si_3N_4$ phase work as scattering centers against electron transfer, resulting in a lowered NTC-to-PTC transition point (below $650^{\circ}C$). Such characteristics were correlated to the fast heating speed (as compared to the commercial models) and to the prevention of the high temperature overshooting of the nitrogen-doped SiC igniter.

• Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.31-39
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• 2022

To clarify the factors influencing the physical properties of fish after heat treatments, we investigated changes in the properties of proteins in the dorsal ordinary and dark muscle of yellowtail (Seriola quinqueradiata) heated under different conditions commonly used for the purposes of food hygiene. High-temperature/short-time heating (85℃ for 90 s and 75℃ for 60 s) affected the protein solubility more than low-temperature/long-time heating (63℃ for 30 min). Sodium dodecyl sulphate-polyacrylamide gel electrophoresis and differential scanning calorimetry showed that low-temperature/long-time heating reduced the degree of actin denaturation in fish compared with that by other heating conditions. In addition, collagen solubility was enhanced with low-temperature/long-time heating. Therefore, these results suggest that differences in the degree of actin and collagen denaturation are responsible for the enhanced meat tenderness and diminished meat shrinkage, resulting from low-temperature/long-time heating.

• Korean Journal of Poultry Science
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• v.17 no.2
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• pp.127-133
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• 1990

This study was undertaken to find out the effect of heating time and temperature, pH and NaCl concentration on the heat stability of egg albumen gel during heat treatment. With the transient decrease at 110-$130^{\circ}C$, hardness of heat-set albumen gel was increased as the heating temperature increased. The cohesiveness showed similar trend as well. The lightness was decreased while the yellowness was increased as the heating time and temperature increased. Heat-set albumen gel showed maximum hardness at pH 4.5-5.0 and pH 9.0 High heat treatment($120^{\circ}C$, 30min) showed higher hardness at alkaline range compared to low heat treatment($96^{\circ}C$, 30min.). Color of the albumen gel was relatively dark at acidic range and bright at alkaline range. High heat treatment caused darker albumen gel at alkaline range and brighter albumen gel at acidic range. The addition of NaCl increased hardness and cohesiveness of the albumen gel and improved the lightness after high heat treatment regardless of NaCl concentration.