• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.203-205
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• 2014

This paper is suggesting about glass melting technology, using both plasma and combustion heat source. The mixed flame was formed to flow pattern of turning by plasma and combustion in melting zone. The burning time was extremely extended for vitrification of raw materials in melting zone, as a result, meting time was significantly reduced. This system was designed to smaller size than existing glass melting facilities. We had achieved to 30% energy saving, due to reduce residence time of melted materials inside furnace.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.167-167
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• 2010

Ge-Sb-Se계 칼코게나이드 유리의 Melting 조건변화에 따른 특성변화를 연구하였다. Glass melting 조건(homogenization-temperature, homogenization-time, annealing) 에 따라 제작된 칼코게나이드 유리 bulk를 FT-IR, XRD, SEM 등의 분석장비를 이용하여 특성을 분석하였다. Homogenization temperature가 높을수록 석영관 급냉 시 발생되는 mechanical stress와 내부응력차로 인해 칼코게나이드 유리 깨짐현상이 증가하였으며 조성비와 melting 조건에 따라 XRD분석에서 확인되지 않는 미소결정이 SEM 분석결과 관찰되었다. 본 연구를 통해 칼코게나이드 유리의 melting 조건에 따른 경향성을 확인할 수 있었다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.12
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• pp.1774-1783
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• 1998

The transition from steady laminar to chaotic convection in a glass melting furnace specified by upper surface temperature distribution has been studied by the direct numerical analysis of the two and three-dimensional time dependent Navier-Stokes equations. The thermal instability of convection roll may take place when modified Rayleigh number($Ra_m$) is larger than $9.71{\times}10^4$. It is shown that the basic flows in a glass melting furnace are steady laminar, unsteady periodic, quasi-periodic or chaotic flow. The dimensionless time scale of unsteady period is about the viscous diffusion time, ${\tau}_d=H^2/{\nu}_0$. Through primary and secondary instability analyses the fundamental unsteady feature in a glass melting furnace is well defined as the unsteady periodic or weak chaotic flow.

• 보존과학연구
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• s.21
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• pp.57-75
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• 2000

We performed the scientific analysis through composition analysis, micro-structure investigation, melting point and hardness test to the glass beads excavated at Naesanri in Gosung. Through this investigation, we could examine closely the characterization of raw materials and manufacture technique As a result of micro-structure investigation of glass beads, it appeared that the bubbles in glass beads have remained. Coloring agents of yellow glass bead was remained to the shape of inclusion. And on observing the transparent solid particle, we can know that these do not melt the raw materials because of low melting temperature of a crucible. The result of composition analysis of all glass beads using ICP, these were classified as $Na_2O_2$-$SiO_2$ type of glass. Also, these added to $AI_2O_3$ to improve the durability. The value of Vickers hardness of glass beads appeared the HV 490-530. The HV 1,440 of the transparent solid particle was much more than that of inner glass bead. This means that raw materials do not melt because of a low melting temperature of a crucible. The result of melting temperature analysis of glass beads using DSC/TGA, it was measured about $1,250^{\circ}C$.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.7
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• pp.919-927
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• 1997

The main purpose of this study is to determine bifurcation as the primary instability of a glass melting furnace. Steady-state and unsteady characteristics of natural convection in the partially open cavity as appeared in a glass melting furnace is investigated by using numerical analysis. Three types of convection, such as steady laminar, unsteady periodic or unsteady quasi-periodic convection may occur according to the temperature difference between upper two isothermal surfaces along the depth of cavity in a glass melting furnace. In the temperature difference of 150-900 K between batch and free surface, the larger the temperature difference, the weaker the convection strength and unsteadiness. Since the glass viscosity is increasing exponentially in the lower temperature, the batch freezes the thermofluidic field especially below the surface of it. If the depth of cavity is 0.5 m, the bifurcation to time-dependent natural convection may occur in the range of 60-650 K. If that is 1.0 m, it may occur in the whole range of temperature difference.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.11
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• pp.3706-3713
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• 1996

A numerical study on natural convection induced by free surface heat flux and cold left and hot right walls in glass melting furnaces has been performed. A function of heat flux derived from the combustion environments of actual glass melting furnace is applied to thermal boundary condition at free surface. Fundamentally there exist two flow cells in cavity (left counterclockwise one and right clockwise one). The effects of heat flux and Rayleigh number are investigated through two-dimensional steady-state assumption. The convection strength of two flow cell located in left region continuously increases. In the mean time the strength of flow cell in right region increases and then decreases. Critical Rayleigh number in which two flow cells take place above and below show linear dependence on the free surface heat flux. To maintain the traditional flow pattern (left and right flow cells) in glass melting furnace, Rayleigh number is recommended to be below 10$^{5}$ .

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.2
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• pp.215-219
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• 1998

This paper presents a practical application of fuzzy logic control to temperature control of glass melting furnace. Due to the characteristics of glass melting furnace, a hybrid algorithm of conventional PI controller and fuzzy logic controller is proposed and discussed. Practical implementation results of the production furnace showed the effectiveness of the proposed control algorithm.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1206-1212
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• 2022

Cold-crucible induction melting (CCIM) technology has been intensively studied as an advanced vitrification process for the immobilization of highly radioactive waste. This technology uses high-frequency induction to melt a glass matrix and waste, while the outer surface of the crucible is water-cooled, resulting in the formation of a frozen glass layer (skull). In this study, for the fabrication of borosilicate glass waste form, CCIM operation test with 60 kg of glass per batch was conducted using surrogate wastes composed of Cs, Sr, and Nd as a representative of highly radioactive nuclides generated during spent nuclear fuel management. A 60 kg-scale glass waste form was successfully fabricated through melting and draining processes using a CCIM system, and its physicochemical properties were analyzed. In particular, to enhance the controllability and reliability of the draining process, an air-cooling drain control method that can control draining through air-cooling near drain holes was developed, and its validity for draining control was verified. The method can offer controllability on various draining processes, such as molten salt or molten metal draining processes, and can be applied to a process requiring high throughput draining.

• Korean Journal of Metals and Materials
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• v.46 no.2
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• pp.65-68
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• 2008

Generally CCM (cold crucible melting) is not suitable for melting glass. However, in this study we described the quantitative relationship between the basic property of glass and power balance, the power absorption in the melt, the losses in the coil and the cold crucible, for melting glass in CCM. The dependence of power balance on the applied frequency and the electric conductivity has been found. Above 300 kHz, the glass (B) contained alkali ion which has the low resistance $3.0{\Omega}{\cdot}cm$ at $900^{\circ}C$ and $1.36{\Omega}{\cdot}cm$ at $1,100^{\circ}C$ was melted easily and 60% of the overall power was absorbed in the melt and 30% and 10% of the overall power was lost in the cold crucible and coil respectively. Under the same condition, the glass (A) contained non-alkali ion was not melted easily and 50% of the overall power was absorbed in the melt and 40% and 10% of the overall power was lost in the cold crucible and coil respectively. In conclusion, the small absorbed power of the overall power in melt prevented a successful melting as for glass A, and the successful melting depends on the relative size of the absorbed power in melt irrespective of the melting volume. Hence, as typical for direct induction heating method(CCM), the successful melting strongly depended on the chosen working frequency based on electric conductivity of glass, power balance and the control of the critical power which was absorbed in melt.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1229-1232
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• 2005

We report the method of preventing the grey color of Bi based glass frits caused by reduction of $Bi_2O_3$. To prevent reduction of $Bi_2O_3$, we controlled the melting temperature. Low melting temperature reduces the reduction of $Bi_2O_3$ and that makes clarity transparent glass cullets. After firing, glass frits that melted at lower temperature showed better transparency. To prevent the browning, we used some additives like CuO, $CeO_2$, CoO and $TiO_2$. The colors of glass cullets were varied according to additives. After firing, dielectric layer contained additives showed better transparency than the one without additives. In the point of reaction between dielectric layer and Ag electrode, CuO was the most effective additive in preventing the yellowing.