• Conservation and Restoration of Cultural Heritage
• /
• v.1 no.1
• /
• pp.39-48
• /
• 2012

The first twenty-five years of scientific study within Korea on Korean traditional ceramics has been characterized as a bridging effort to understand the rich field of artistic ceramic masterpieces on one hand with analytic results gained from mounds of broken shards and kiln wastes on the other. First shard pieces were collected directly from the waste mounds, but most of the analyzed shards were provided by art historians and museum staffs directly involved in systematic excavations. The scientific study is viewed as one of many complimentary ways in learning about the multi-faceted ceramics culture, ultimately connecting human spirits and endeavors from the past to the present to the future. About 1350 pieces of analyzed shards have been so far collected and organized according to the production location and time period. From the experimental results of the analysis, the compositional and microstructural characteristics of bodies and glazes have been deduced for many kiln sites of Goryeo and Joseon dynasties. Except for a few local kilns, porcelain stone was used as body material in both dynasties. The principle of mixing a clay component with a flux material was used in Korean glazes as was in China. The clay component different from body clay was often used early on. In Gangjin a porcelain material appropriate for whiteware body was mixed for celadon glaze, and in Joseon Gwangju kilns glaze stone was chief clay material. The use of wood ash persisted in Korea even in making buncheong glazes, but in Joseon whitewares burnt lime and eventually crushed lime were used as flux material.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.13 no.3
• /
• pp.229-233
• /
• 2015

Developing novel anode materials to replace the Pt anode currently used in electrolytic reduction is an important issue on pyroprocessing. In this study, the electrochemical behavior of TiN was investigated as the conductive ceramic anode which evolves O₂ gas during the reaction. The feasibility and stability of the TiN anode was examined during the electrolytic reduction of UO₂. The TiN anode could electrochemically convert UO₂ to metallic U in a LiCl–Li₂O molten salt electrolyte. No oxidation of TiN was observed during the reaction; however, the formation of voids in the bulk section appeared to limit the lifetime of the TiN anode.

• Journal of Environmental Health Sciences
• /
• v.29 no.1
• /
• pp.51-61
• /
• 2003

Pollution purification using titanium dioxide (TiO$_2$) photocatalyst has attracted a great deal of attention with increasing number of relent environmental problems. Currently, the application of TiO$_2$ photocatalyst has been focused on purification and treatment of waste water. However. the use of conventional TiO$_2$ powder photocatalyst results in disadvantage of stirring during the reaction and of separation after the reaction. And the usage of artificial UV lamp has made the cost of photocatalyst treatment system high. Consequently, we herein studied the pilot-scale design to aid in optimization of the energy-saving process for more through development and reactor design by solar light/UV lamp/ TiO$_2$system. In this study, we manufactured the TiO$_2$sol by sol-gel method. According to analysis by XRD, SEM and TEM, characterization of TiO$_2$ sol were nano-size (5-6 nm) and anatase type. Inorganic binder (SiO$_2$) was added to TiO$_2$ lot to be coated for support strongly, and support of ceramic bead was used to lower separation rate that of glass bead The influences were studied of various experimental parameters such as TiO$_2$ quantity, pH, flow rate. additives, pollutants concentration, climate condition and reflection plate by means of reaction time of the main chararteristics of the obtained materials. In water treatment system, variable realtor as solar light/ or UV lamp according to climate condition such as sunny and cloudy days treated the phenol and E-coli(Escherichia coli) effectively.

• Journal of Conservation Science
• /
• v.12 no.1 s.15
• /
• pp.1-14
• /
• 2003

Chemical characteristics of whitewares excavated from the of official kiln of the Choseon Dynasty period in Gwangju, Gyeonggido have been stuied using x-ray diffraction, inductively coupled plasma atomic absorption spectrometry and energy dispersive spectrometry. This study shows that most of whitewares excavated from the kiln site are similar in chemistry to each other regardless of their excavated positions and that the their bodies were not made of feldspar minerals. However, the whiteware from sedimentation 1 of waste articles shows mineralogical characters different from those of other sites. This result is in accordance with the report that the whitewares from sedimentation 1 of waste articles have characters different from other sites. The whiteware glaze was produced from raw minerals of both lime and alkali-lime system resulting in wide variation in chemical composition.

• KSBB Journal
• /
• v.22 no.4
• /
• pp.191-196
• /
• 2007

This study used biofilm process, which needs simple operation, maintenance and smaller facility area than conventional activated sludge process with the small plant operation, in the treatment of increasing sewage with the rapid industrial growth. The reactor used in this study consists of one anaerobic and one aerobic chamber filled with waste ceramic and waste vinyl as media and the treated sewage was from restaurant source. The experiment was scaled up from lab. to pilot scale and lasted for about 100 days. We focused on the removal efficiency of organics, nitrogen and phosphorus with constant HRT and continuous aeration. The removal efficiency of $BOD_5$ and SS were 94.33% and 87.77% respectively, which was a satisfaction level. However the removal efficiency of $COD_{Cr}$ was 81.46% somewhat below the desired level of 90%, and that of T-N and T-P showed 71.92% and 21.10% respectively, that was below the expected value. The removal efficiency of $COD_{Cr}$ and T-N in the pilot scale was about 10% low compared with the lab.-scale.

• Journal of Hydrogen and New Energy
• /
• v.31 no.2
• /
• pp.169-176
• /
• 2020

There is a growing interest in hydrogen energy utilization since an alternative energy development has been demanded due to the depletion of fossil fuels. Hydrogen is produced by the reforming reaction of natural gas and biogas, and the electrolysis of water. An solid oxide electrolyte cell (SOEC) is reversible system that generates hydrogen by electrolyzing the superheated steam or producing the electricity from a fuel cell by hydrogen. If the water can be converted into steam by waste heat from other processes it is more efficient for high-temperature electrolysis to convert steam directly. The reasons are based upon the more favorable thermodynamic and electrochemical kinetic conditions for the reaction. In the present study, steam at over 180℃ and 3.4 bars generated from a boiler were converted into superheated steam at over 700℃ and 3 bars using a cylindrical steam superheater as well as the waste heat of the exhaust gas at 900℃ from a solid refuse fuel combustor. Superheated steam at over 700℃ was then supplied to a high-temperature SOEC to increase the hydrogen production efficiency of water electrolysis. Computational fluid dynamics (CFD) analysis was conducted on the effects of the number of 90° elbow connector for piping, insulation types and insulation layers of pipe on the exit temperature using a commercial Fluent simulator. For two pre-heater injection method of steam inlet and ceramic wool insulation of 100 mm thickness, the highest inlet temperature of SOEC was 744℃ at 5.9 bar.

• Journal of Energy Engineering
• /
• v.13 no.4
• /
• pp.291-295
• /
• 2004

Heat regenerator attached in small-scale regenerative radiant tube burner was designed using the theoretical computation code and was confirmed the performance of waste heat recovery ratio. From the computation, when ceramic ball of 4-5kg was used, temperature efficiency and available waste heat recovery ratio were predicted 80% and 70%, respectively. Similar efficiencies were obtained from the experiments using LPG. However, since exhaust gas temperature entered into regenerator was below 850$^{\circ}C$ which was moth lower than that we expected. air preheating temperature was lowered below 800$^{\circ}C$.

• Membrane Journal
• /
• v.24 no.3
• /
• pp.201-212
• /
• 2014

This study was performed to discover the optimum operation conditions for the advanced water treatment using the ceramic membrane, introduced the first in the nation at the Y water treatment plant (WTP). The result of investigation to find the optimum operation conditions which can continue preserving the filtration performance as well as satisfying both the economics and the water quality is as follows. In the ordinary water quality condition of the Y WTP, the optimum filtration time(the backwash period), which can minimize the production of backwash waste and preserve the membrane performance was examined to be 4.0 hours on basis of institution capacity ($16,000m^3/day$). Examining the recovery rate of TMP from the chemical cleaning (CIP) discovered that the inorganic contaminants, which cause membrane fouling, such as iron, manganese, aluminum, were removed through the acidic cleaning using citric acid, whereas the membrane recovery rate was found to be low. But, on the other hand, the TMP was recovered to the initial value from the alkali cleaning using the NaOCl. Therefore, the main contaminant causing the fouling was determined to be hydrophilic organic compound( biopolymer). The membrane recovery rate is highly influenced by the temperature of the cleaning chemical. That is, the rate increased with increasing temperature.

• Journal of the Korea Institute of Building Construction
• /
• v.16 no.5
• /
• pp.421-428
• /
• 2016

In this work, pozzolanic activities of various waste materials were compared with those of well-known by-product pozzolanic materials. Undensified and densified silica fume, ASTM class F and class C fly ash, and metakaolin were chosen as well-known pozzolanic materials, and bentonite powder, ceramic powder obtained from wash basin, and waste glass wool, which can possibly possess pozzolanic property, were chosen for comparison. Drop in electrical conductivity at $40^{\circ}C$ saturated lime solution was measured for each materials. The amount of Ca(OH)2 decomposed from cement paste at $450{\sim}500^{\circ}C$ was also measured to evaluate pozzolanic activity. The 28 day compressive strength were used to observe the mechanical property enhanced by incorporation of various waste materials. According to the experimental results, using "difference between maximum conductivity value and conductivity value at 4 hour" was found to be a reasonable approach to determine pozzolanic activity of a material. Pozzolanic activity measured using electrical conductivity correlates very well with that measured using the amount of Ca(OH)2 remained in the cement paste. Relatively good agreement was also found with electrical conductivity and 28 day compressive strength. It was found that electrical conductivity measurement can be used to evaluate pozzolanic activity of unknown materials.

• Nuclear Engineering and Technology
• /
• v.54 no.9
• /
• pp.3250-3259
• /
• 2022

A new approach to the use of rice straw as a difficult-to-recycle agricultural waste was proposed. Potassium aluminosilicate was obtained by spark plasma sintering as an effective material for subsequent immobilization of ¹³⁷Cs into a solid-state matrix. The sorption properties of potassium aluminosilicate to ¹³⁷Cs from aqueous solutions were studied. The effect of the synthesis temperature on the phase composition, microstructure, and rate of cesium leaching from samples obtained at 800-1000 ℃ and a pressure of 25 MPa was investigated. It was shown that the positive dynamics of compaction was characteristic of glass ceramics throughout the sintering. Glass ceramics RS-(K,Cs)AlSi₃O₈ obtained by the SPS method at 1000 ℃ for 5 min was characterized by a high density of ~2.62 g/cm³, Vickers hardness ~ 2.1 GPa, compressive strength ~231.3 MPa and the rate of cesium ions leaching of ~1.37 × 10^-7 g cm^-2·day^-1. The proposed approach makes it possible to safe dispose of rice straw and reduce emissions into the atmosphere of microdisperse amorphous silica, which is formed during its combustion and causes respiratory diseases, including cancer. In addition, the obtained is perspective to solve the problem of recycling long-lived ¹³⁷Cs radionuclides formed during the operation of nuclear power plants into solid-state matrices.