• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.4
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• pp.563-565
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• 2020

Turbot Scophthalmus maximus can be cultured at a higher density and has a faster growth rate than olive flounder Paralichthys olivaceus, making it an attractive alternative for flounder farmers in Korea. As it is a relatively new species to Korean farming environments, there is no general farming protocol, which takes multiple generations to develop, for turbot in Korea. Nevertheless, we applied breeding technology to develop a stock, which we considered first-generation turbot. Then we compared its growth rate (an important economic trait) to different populations (the original stock of Korean turbot, French turbot, and Chinese turbot). The four different populations were grown in similar culture conditions. First-generation Korean turbots grew about 28% faster than all others. We will continue to select for important traits such as color, disease resistance, and heat tolerance in this turbot broodstock; we believe that with the appropriate selection process, Korean turbot should become competitive in the markets, and will become a major farming species in the Korean aquaculture industry.

• Journal of the Korean Society of Safety
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• v.30 no.3
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• pp.38-44
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• 2015

For this study, fire tests were performed targeting household items (Sofa, Drawer, Refrigerator, Washing machine) using a large cone calorimeter (Large Scale Cone Calorimeter, LSC). The data were obtained focusing on the fire characteristic of the data when the actual fire occurs. The study results showed the following mean HRR of the household items; drawer 2843 KW, sofa 2939 KW, washing machine 719 KW, refrigerator 2907 KW, and THR is found in sofa 2202 MJ, drawer 1559 MJ, refrigerator 1193 MJ, washing machine 627 MJ. From the result, it could be found that the sofa can cause significant heat generation when the fire occurs, and the flashover tendency was found relatively high in compartment fire. In addition, a weight of the four our household items was reduced sharply in a similar time (20min before and after) degree after ignition. The drawer and sofa which has a high heat release can be considered to speed up the fire spread as their weight decrease rapidly and showed relatively weak to the fire compared to the refrigerator and washing machine.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.4
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• pp.99-104
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• 2020

In this study, the temperature distribution and heat transfer characteristics of each component in a solenoid motor system were numerically investigated when heat is generated by the steel pad attached to the solenoid ring of the motor. It was found that the internal airflow was complicated by the inflow velocity of air and the rotation of guide rollers and solenoid rings. Based on the numerical results, the tendency for temperature changes in the steel panel was lower due to the contact of the cooling air in the front in the rotational direction, and the peak temperature was at the front of the center. In particular, it was confirmed that as the air inflow rate was increased, the temperature was reduced due to strong convection. The temperature of the iron plate pad was decreased as the convective heat transfer coefficient was linearly increased with increasing airflow around the solenoid ring. In addition, the temperature of the iron plate panel was rapidly increased with increasing heat generation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.4
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• pp.1376-1384
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• 1996

Measuring the velocity of fluid flow, semiconductor flow sensors are widely used in the various fields of engineering and science such as the semiconductor manufacturing processes and electronic control engines for automobiles. In the near future, this type of sensors will replace present hot wire type sensors or other type flow sensor due to its low price, easy handling and small size. To develop the advanced semiconductor flow sensor, it is necessary to obtain characteristics of the flow and the heat transfer around the sensor in advance. In the present study, the theoretical analysis including mathematical modeling and numerical calculation to predict the characteristics of heat transfer and flow field around the sensor was carried out. The main parameters for optimum design of the flow sensor are the free stream velocity, the heat generation rate of silicon arm and the distance between arms. Effects of these parameters on flow and heat transfer around the sensor and the temperature difference between arms are examined.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.702-708
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• 2017

The heat generation rate in a telecommunications cabinet keeps increasing due to the increased usage of mobile devices. Insufficient removal of the heat increases the cabinet temperature, which results in the malfunction of the electronic devices. In this study, tests were conducted on aluminum and plastic heat exchangers for cooling a telecommunications cabinet, and the results were compared with theoretical predictions. The aluminum heat exchanger comprised counter flow parallel channels with 4.5-mm pitch, and the plastic heat exchangers comprised cross or cross-counter flow triangular channels with 2.0-mm pitch. The volume of the cross flow heat exchanger was the same as that of the aluminum heat exchanger, and the volume of the cross-counter heat exchanger was 33% larger than that of the aluminum heat exchanger. The results show that the heat transfer rate is the highest for the cross-counter heat exchanger and lowest for the aluminum one. The temperature efficiency of the cross-counter heat exchanger was 56% higher than that of the aluminum one and 20% higher than that of the cross flow heat exchanger. The pressure drop of the cross-counter heat exchanger was approximately the same as that of the aluminum one. The heat exchange efficiency was the highest for the cross-counter heat exchanger and lowest for the cross flow heat exchanger. The theoretical analysis somewhat overestimated or underestimated the data.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.279-283
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• 2009

Distributed generation(DG) of combined cooling, heat. and power(CCHP)has been gaining momentum in recent year as efficient, secure alternative for meeting increasing energy demands. This paper presents the energy performance of microturbine CCHP system equipped with an absorption chiller by modelling it in hospital building. The orders of study were as following. 1)The list and schedule of energy consumption equipment in hospital were examined such as heating and cooling machine, light etc. 2) Annual report of energy usage and monitoring data were examined as heating, cooling, DHW, lighting, etc. 3) The weather data in 2007 was used for simulation and was arranged by meteorological office data in Daejeon. 4) Reference simulation model was built by comparison of real energy consumption and simulation result by TRNSYS and ESP-r. The energy consumption pattern of building were analyzed by simulation model and energy reduction rate were calculated over the cogeneration. As a result of this study, power generation efficiency of turbine was about 30% after installing micro gas turbine and lighting energy as well as total electricity consumption can be reduced by 40%. If electricity energy and waste heat in turbine are used, 56% of heating energy and 67% of cooling energy can be reduced respectively, and total system efficiency can be increased up to 70%.

• Journal of the Korean Solar Energy Society
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• v.33 no.4
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• pp.70-79
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• 2013

These day cities experience serious climatic changes due to environmental load caused by disturbance in the circulation systems of water resources and energy. As technological improvement to respond to various climatic changes and disasters are also requested in the field of construction, inter-disciplinary studies linked to the establishment of sustainable environmental control and energy systems is required in a consilient perspective. This study aims to infer correlations in the impact of environmental changes caused by rooftop greening system on the photovoltaic power generation efficiency through computer simulation in an integrated perspective. By doing so, it seeks to provide basic study for developing a photovoltaic system integrated with building revegetation that is sustainable in environmental and resource aspects. A simulation showed that, in the case of sunshine hours in June, the green surface indicated temperature lowering effects of $9.19^{\circ}C$ on average compared to the non-green surface and temperature was $9.81^{\circ}C$ lower. Due to such greening effects, at the highest sunlight timepoint in June, Pmpp improved 119W and heat loss rate dropped 7.8%.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.239-243
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• 1997

The heat generation is the most important problem in the motor integrated spindle. Double cooling jacket in necessary to reduce the thermal displacement and to get the stable temperature disribution for the housing. In this study, the effects of temperature distribution and thermal displacement for the spindle system according to the variation of cooling oil flow rate are investigated experimentally on the motor-integrated spindle with double cooling jacket system. The experimental spindel system is composed with the angular contact steel ball bearings, oil-air lubrication, air or oil jacket cooling system.

• Publications of The Korean Astronomical Society
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• v.11 no.1
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• pp.125-137
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• 1996

The collision of two particles in the accretion disk may lead to be a mechanism of heat generation. By using hydrodynamic equations, the mean free path, the collision frequency and the deflection angle due to the collision of the particles are derived as a function of the mass accretion rate. The mean free path seems to be a smaller fraction compared to the dimension parameter of the system. The radiative flux in the disk is obtained under the influence of the collision of the particles.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.889-892
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• 2008

This study, having combined and displaced fly ash known as admixture material that delays hydration reaction with coarse particle cement("CC" hereinafter) collected in particle classification method during ordinary portland cement("OPC" hereinafter), reviewed the hydration heat characteristics affecting the concrete. To reduce hydration heat, the study plain-mixed which used 100% OPC for WB 50% level 1, displaced CC at level 3 of 25%, 50% and 75% for OPC, and by displacing FA with admixture material at level 5 of 0%, 10%, 20%, 30% and 40%, experimented totally 16 batches. As a result of experiment, in the case of flow, the more CC displacement rate increased, the more it tended to decrease, and the more FA displacement rate increased, the more it decreased. As for simple adiabatic temperature rise by the CC and FA displacement rates, it decreased as displacement rate increased, and particularly in the case of FA40, temperature rise amount, $5.8{\sim}7.4^{\circ}C$, was very low. Compressive strength decreased in proportion to displacement rate, however strength reduction increment was shown to decrease with age progress.