• Food Science of Animal Resources
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• v.20 no.2
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• pp.107-113
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• 2000

This study was carried out to investigate the effects of temperature activation and agitation on lipolysis of goat milk. When goat milk was temperature activated twice at intervals of 12hours, free fatty acids were significantly increased after the first activation, but increased slightly during the re-cooling period and after the second activation. Lipolysis of the goat milk warmed at $30^{\circ}C$ was significantly facilitated during the re-cooling period. Lipolysis of the goat milk warmed at $30^{\circ}C$ was much higher than those warmed at $10^{\circ}C$ and $40^{\circ}C$ respectively. The highest lipolysis was occurred when the goat milk was warmed at $30^{\circ}C$ for 5 minutes after pre-cooling for 24 hours at $40^{\circ}C$. However, any significant difference was not found in the milk warmed at $40^{\circ}C$, regardless of the pre-cooling period. Lipolysis of the goat milk warmed and agitated at $30^{\circ}C$ was significantly facilitated during the re-cooling period. The lipolysis of that at $30^{\circ}C$ was significantly facilitated during the re-cooling period. The lipolysis of that at $30^{\circ}C$ was much enhanced with agitation. The lipolysis was much higher when agitated at $30^{\circ}C$ than when agitated at $10^{\circ}C$. The length of agitation time at $30^{\circ}C$ didn't give any effect on lipolysis.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.5
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• pp.66-71
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• 2009

The solar photovoltaic power generator can get more power with the higher solar radiation quantity. However, if the higher solar radiation quantity on cell becomes high temperature, the efficiency of generate will be reduced. To install cooling system for this kind of device can be the way to solve high temperature problem on cell but another problems after install it such as increasing of solar generated quantity problem cost to install cooling system and cost to be maintained cooling system weren't discussed to practical use this system. So the present paper described about effect and commercial business possibility of cooling system. After installing a cooling system the results of experiment about 5.76[%] average annual increasing of solar photovoltaic can expect.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.11
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• pp.1267-1273
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• 2009

Hot press forming can produce high-strength components by rapidly cooling between closed punch and die after hot forming using quenchable boron steel austenized in a furnace. In the hot press forming process, the cooling rate is influenced by the size, position and arrangement of the cooling channel and the file condition of cooling water in the die. Also, mechanical properties of the final components and operation time are related to cooling rate. Therefore, the design of optimized cooling channel is one of the most important works. In this paper, the effect of position and size of the cooling channel on the cooling rate was investigated by using design of experiment and FE analysis in hot press bending process. Therefore the optimum cooling channel ratio was presented in the HPB.

• Journal of Korea Foundry Society
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• v.26 no.1
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• pp.17-26
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• 2006

The substitution of cooling method from water quenching to air cooling after solution heat treatment was aimed for the development of a convenient and economical heat treatment process of duplex stainless steels without deterioration of mechanical and corrosion resistant properties for the industry. In order to achieve this goal, the mechanical properties and corrosion properties of a ASTM A890-4A duplex stainless steel were systematically investigated as functions of casting condition and cooling method after solution heat treatment. A 3-stepped sand mold and a permanent Y-block mold were used to check the effects of solidification structure and cooling rate after solution heat treatment. The microstructural characteristics such as the ferrite/austenite phase ratio and the precipitation behavior of ${\sigma}$ phase and carbides were investigated by combined analysis of OM and SEM-EDX with an aid of TTT diagram. Hardness and tension test were performed to evaluate the mechanical properties. Impact property at $-40^{\circ}C$ and corrosion resistance were also examined to check the possibility of the industrial application of this basic study. Throughout this investigation, air-cooling method was proved to effectively substitute for water-quenching process after the solution heat treatment, when the duplex stainless steel was sand mold cast with a thickness below 15 mm or permanent mold cast with a thickness below 20 mm.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.207-210
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• 2008

The effects of boron additions in steels have long been recognized as very important, mainly with respect to hardnability of heat treatable steels. we investigated the effect of the microstructure and mechanical properties with cooling condition after heat treatment of the boron-treated(${\fallingdotseq}8{\sim}18ppm$) low carbon(${\fallingdotseq}0.2%C$) low alloy steel. The specimens were austenitised for 10 min at $910^{\circ}C$, cooled for the various periods of time from 10 sec to 30 sec or with water after forming for 15 sec. After cooling, mechanical properties were measured by tensile test and hardness test. For analysis of microstructure, Optical were carried out.

• Journal of the Korea Concrete Institute
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• v.12 no.3
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• pp.95-102
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• 2000

Crack control due to temperature is an important factor for the mass concrete structure. Pre-cooling is the effective system to reduce the highest temperature of mass concrete. In this study, for pre-cooling, cooling water, cooling water with ics flake are used. The results of a series of experimental studies indicate that the changes in properties of fresh concrete after cooling are of low degree, and compressive strength of concrete is changed very little by cooling. The adiabatic temperature rise is also measured with pre-cooling concrete specimens. It is shown that hydration heat characteristics of cement and concrete were largely affected by pre-cooling.

• Journal of the Semiconductor & Display Technology
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• v.17 no.3
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• pp.100-103
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• 2018

Due to the plasma applied from the outside, which acts as an etchant during the etching process, considerable heat is transferred to the wafer and a separate cooling process is performed to effectively remove the heat after the process. In this case, a direct cooling method using a refrigerant is suitable for cooling through effective heat exchange. The direct cooling method using the refrigerant using the latent heat exchange is superior to the cooling method using the sensible heat exchange. Therefore, in this paper, AMESim is used to design a direct refrigerant cooling system using latent heat exchange simulator was built.The constructed simulator is reliable compared with the actual experimental results. It is expected that this simulator will help to design and search for optimal process conditions.

• Journal of the Korea Institute of Building Construction
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• v.4 no.4
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• pp.87-94
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• 2004

As the bentonite is main material to prevent from collapse of drilling hole at underground excavation works, it is increased using quantity on construction industry day by day. But, the discarded bentonite that is over using at underground excavation works is caused various enviromental trouble as soil and water pollution est. Therefore, this study aims to propose a foundamental report for pozzolan reaction of discarded Bentonite powder by heat-treatment and cooling as concrete mineral admixture. To find out pozzolan reaction ability of discarded Bentonite powder by indirect cooling & cooling using of water after heat-treatment, the experiments are excuted flow test & compressive strength on age of mortar using discarded Bentonite powder. As a result of this study, discarded Bentonite powder can be utilized as concrete mineral admixture by heat-treatment and especially, pozzolan reaction ability of discarded Bentonite powder is superior to the situation of 600℃. 60min ＆amp; cooling using of water.

• Advances in materials Research
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• v.5 no.1
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• pp.21-34
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• 2016

Fire is one of the most destructive powers to which a building structure can be subjected, often exposing concrete elements to elevated temperatures. The relative properties of concrete after such an exposure are of significant importance in terms of the serviceability of buildings. Unraveling the heating history of concrete and different cooling regimes is important for forensic research or to determine whether a fire-exposed concrete structure and its components are still structurally sound or not. Assessment of fire-damaged concrete structures usually starts with visual observation of colour change, cracking and spalling. Thus, it is important to know the effect of elevated temperatures on strength retention properties of concrete. This study reports the effect of elevated temperature on the mechanical properties of the concrete specimen with polypropylene fibres and cooled differently under various regimes. In the heating cycle, the specimen were subjected to elevated temperatures ranging from $200^{\circ}C$ to $800^{\circ}C$, in steps of $200^{\circ}C$ with a retention period of 1 hour. Then they were cooled to room temperature differently. The cooling regimes studied include, furnace cooling, air cooling and sudden cooling. After exposure to elevated temperatures and cooled differently, the weight loss, residual compressive and split tensile strengths retention characteristics were studied. Test results indicated that weight and both compressive and tensile strengths significantly reduce, with an increase in temperature and are strongly dependent on cooling regimes adopted.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.6
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• pp.59-65
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• 2010

This study deals with the characteristic of refrigerant for heat-treatment deformation control of SCM415 steel. The control of heat-treatment deformation must need the progress of production parts for an industry machine. Most of the deformation is occurred on unequal cooling. The unequal cooling is occurred by a property of quenching refrigeration. When a heated metal is deposited in the refrigeration, the cooling speed is so slow in early period of cooling because of occurring a steam-curtain. After more cooling, the steam-curtain is destroyed. In this progress, the cooling speed is very fast. The object of this study is to control the deformation of heat-treatment for the part of the industry machine by improving the conditions of quenching. The cooling curves and cooling rates of water, oil and polymer solution are obtained and illustrated. From the characteristics of the quenching refrigerant, the effects of heat-treatments on the thermal deformation and fatigue strength are also investigated.