• The Journal of the Petrological Society of Korea
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• v.26 no.4
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• pp.361-371
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• 2017

We investigated geochemical characteristics of the Dodong Basaltic Rocks in the lower part of the Ulleung Island. They have lithological range of alkali basalt to trachybasalt, belonging to Na and K subseries of alkaline series. They mostly fall within the field of alkalline within-plate basalts on tectonic discrimination diagrams, and then plot in the field of oceanic island basalt (OIB). Geochemically, extension of lithospheric mantle and asthenospheric upwelling after East Sea under an Cenozoic extensional tectonic setting might be a heat source for partial melting of the enriched lithospheric mantle, which might generate the basaltic magma. But we cannot exclude that mantle plume might also be a heat source for melting of the lithospheric mantle.

• Korean Journal of Crystallography
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• v.7 no.2
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• pp.147-155
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• 1996

Floating Zone Image furnace with halogen lamps as heat source has been made and applied to the growth of high-Tc superconductor Bi2Sr2CaCu2O8. The manufactured crystal growth equipment is composed of holder unit for setting the halogen lamps at the focal point of the elliptical mirror, image furnace with maximum temperature of 1800℃ with 1kW halogen lamps, cooling unit, feeding unit for supplying source material to the molten zone, pulling unit for crystal growth, and the control unit in the range of 2mm/hr -40 mm/hr vertical movement and 15rpm - 12rpm rotation. Bi2Sr2CaCu2O8 fibers have been grown with 300W halogen lamps and characterized with XRD, SEM and EDS. The growth condition was air atmosphere, growth speed 3∼4mm/hr, rotation speed of upper and lower part 20∼25 rpm. The fiber was composed of 20∼25 rpm matrix phase and secondary phases such as (Sr,Ca)CuO2 and (Sr,Ca)2CuO3.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.6
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• pp.75-80
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• 2013

In this study, a forced ignition method with a plasma jet torch is studied in Mach 2 laboratory scaled wind-tunnel. The hyper-mixer is used as a mixer. For two normal injection cases, the one is collided against a wedge plate of the hyper-mixer and the other is directly injected into the cold main flow. For the first case, the hyper-mixer disperses the injected fuel, leading to the mixing enhancement. Furthermore, the fuel-air mixture is provided into the plasma hot gas, which enhances the combustion performance. However, the direct injection into the main flow method spends amount of fuel without ignition in the cold supersonic flow. In the end, for the forced combustion, it is important to supply the fuel-air mixture into the heat source.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.372-378
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• 2012

This study was carried out in order to determine the optimum length of a roll type PE pipe heat exchanger employed in the water-to-water heat pump system using the waste heat of the heated effluent flowed out from thermal power generation plants as a heat source. And the heat pump system of 30 RT for an experimental test was designed and manufactured. And also PE pipes were employed to recover the waste heat from the heated effluent. The inside diameter of PE pipe heat exchanger was 20 mm, the thickness was 2 mm and the diameter of a roll was 1,000 mm. And from the results of this study, we found that the optimum length of PE pipe heat exchanger was 75 m per the heat pump capacity of 1.0 RT (3.51 kW) and then the heating COP of heat pump system was 3.8.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.666-671
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• 2014

Using positive temperature coefficient (PTC) heater as supplementary heating for diesel engine vehicles with low heat source is a good method to enhance the heating performance during cold start. In this study, the PTC elements were made by using screen printing process for forming ohmic contact layer, and prototype of PTC heater was designed and made for a diesel engine vehicle. In process of designing the PTC heater, the thermal flow analysis of PTC element modules was conducted for verifying the effect of the shapes of contact surface between each of the components (cooling fin, insulator, ceramic element). We also investigated the performance characteristic (heating capacity, energy efficiency, pressure drop) of the PTC heater through the experiments. Therefore, the experimental results indicated that prototype of PTC heater had satisfactory performance. This study will be basis for improving the manufacturing process and increasing the performance of the PTC element and heater.

• Polymer(Korea)
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• v.35 no.3
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• pp.228-231
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• 2011

The rate of vulcanization of nonpolar ethylene-propylene-diene terpolymer(EPDM)/carbon black compounds was investigated by using hot air and microwave as a heating source. The present study parameters such as heating source, sample thickness, and loading of an additive. The compound thickness was the main factor in the hot air vulcanization. It was due to the poor thermal conductivity of EPDM; that is, the thicker thickness, the lower vulcanization rate. For 100% vulcanization, the compound with 3 mm thickness required 7 min at $250^{\circ}C$ in the hot air system. However, the vulcanization of EPDM compounds by microwave system was not affected by the thickness while strongly dependent on the amount of a polar additive, carbon black. A compound with 80 phr of carbon black was perfectly vulcanized within 30 sec. These results suggest that the use of microwave as a heating source is an effective method for the vulcanization of compounds including a polar component.

• Fire Science and Engineering
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• v.24 no.1
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• pp.122-127
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• 2010

The combustion characteristics of phenol foam were analysed using variable external irradiation level (20, 25, 35, 50, and $70kW/m^2$) and in the mixture gas of oxygen/nitrogen. The oxygen index were carried out from the oxygen index tester (KS M ISO 4589-2) and ignition time, critical heat flux, and mass loss rate were carried out from the mass loss calorimeter (ISO 5660-1). As the results of this study, the critical heat flux and average mass loss rate were $28.99kW/m^2$ and $0.56{\sim}1.77g/m^2s$ respectively at the variable external irradiation level. And the limited oxygen index were 45.1% in mixture gas of oxygen/nitrogen. In conclusion, we knew that phenol foam had the best performance than other foam materials in fire safety from all data of this study.

• Korean Chemical Engineering Research
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• v.57 no.5
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• pp.730-734
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• 2019

Thermophoresis is a transport phenomenon of particles driven by a temperature gradient of a medium. In this paper, we discuss the thermophoresis of particles in microfluidic channels. In a non-fluidic, stagnant channel, the thermophoretic transport of micro-particles was found to be larger in proportion to the voltage applied to the platinum wire heat source installed in the channel. The variation of the temperature around the platinum wire depending on the voltage was estimated, by using the Callendar-van Dusen equation. The thermophoretic behavior of nano-particles in the same system was observed, which is similar to that of the microparticles. Finally, we fabricated a Y-shaped microfluidic channel with a platinum wire heat source installed in the channel, to realize the thermophoretic phenomenon of the particles in the suspension flowing through the channel. It is shown that the flow of the suspension can be controlled based on the thermophoretic principle.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.17 no.2
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• pp.30-41
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• 2021

This paper presents the heating performance analysis results of a heat pump system using a dual heat source. In this paper, a dual heat source refers to the ground-coupled heat exchanger using both a surface water heat exchanger (SWHE) and a vertical ground heat exchanger (VGHE). In order to evaluate the system performance, we installed a monitoring system to measure the temperature and power consumption of a heat pump and then collected operation data with 4 different load burdened ratios of the dual heat source heat exchanger. During the whole measurement period, the average heating capacity of a water-to-water heat pump unit was 37.3 kW. In addition, the compressor of the heat pump consumed 9.4 kW of power, while the circulating pump of the dual heat source heat exchanger used 6.7 kW of power. Therefore the average heating coefficient of performance (COP) for the heat pump unit was 4.0, while the entire system including the circulating pump was 2.7. Finally, the parallel use of SWHE and VGHE was beneficial to the system performance; however, further researches are needed to optimize the design data for various load ratios of the dual heat source heat exchanger.

• Applied Chemistry for Engineering
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• v.22 no.3
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• pp.286-290
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• 2011

Syngas was produced out of pellet refuse derived fuel (RDF) produced from an RDF production facility of W city, Korea. A two-stage gasification system was developed to use the RDF char as an auxiliary heat source for gasification reaction. The composition and heating value of syngas as well as the heating value of residual product (char) were measured at a different residence time to investigate the optimal operating condition of the two-stage gasification system for syngas production. The optimal char residence time to minimize the energy cost due to an external heat source supply was also deduced.