Abstract: A process for the recovery of nanoporous silica and sodium fluoride from
hexafluorosilicic acid and sodium silicate under the different molar ratios was studied. In order to
prepare the appropriate solutions of initial compounds 25% of hexafluorosilicic acid and the 18% of
sodium silicate were used. Obtained nanoporous silica and sodium fluoride have been characterized
by XRD, BET, TGA, EDX and SEM.
Abstract: Homogeneous precipitated calcium carbonate(PCC) was synthesized by calcinations,
hydration and carbonation of limestone which has been deposited in Danyang, Korea. In the
reaction process, shapes(scalenohedral and cubic) and sizes(0.2~0.3μm and 2.0μm) of the powder
were controlled by reaction temperature. Synthesized PCC was applied to hand-made paper as filler
and coated paper. For the prepared papers, physical/optical properties(brightness, whiteness, opacity,
roughness, gloss, tensile strength, internal tearing strength, stiffness, bursting strength) and
printability(ink gloss, ink set-off, dry pick, wet pick) were characterized
Abstract: This paper presents a numerical simulation of Automobile Shredder Residue (ASR) chips
motion and combustion in a cement works precalciner. The work was done using the commercial
computational fluid dynamic (CFD) code FLUENT. The aim of this work is to develop an
understanding of the processes within the percalciner to aid in the prediction of ASR chip
aerodynamic and combustion behaviors for its use as an alternative fuel. The effects of the mutual
interactions between ASR chips were simulated by discrete phase modeling approach, while ASR
combustion was simulated by the finite rate devolatilization models. A useful approach to simulate
the characteristics of turbulent gas-particle flow, heat transfer and ASR combustion process in a
precalciner has been demonstrated.
Abstract: Chemical composition and uniaxial compressive stress are varied to observe their effect on
the current-voltage behaviors of ZnO based ceramics. Chemical composition variation produces two
kinds of ceramics showing ohmic and nonohmic current-voltage behaviors. The current at a fixed
voltage is increased with the increase of the compressive stress for both ceramics. Ceramics with
nonohmic behavior shows better reversible return of current-voltage curve when the applied
compressive stress is removed from the ceramic than those with ohmic behavior do. We found out an
appropriate chemical composition showing linear relation between current and stress at a fixed
voltage as a potential application of the ceramic material to pressure sensor.
Abstract: Freeze casting is a useful forming technique to produce complex-shaped ceramic parts. In
order to optimize freeze casting slurries, several processing additives are usually employed.
Therefore, the relationships between additives and suspension characteristic should be understood.
The effects of incorporating processing additives on dispersion and viscosity functions of aqueous
alumina/zirconia and mullite/zirconia suspensions have been investigated.
Abstract: We report on a process in which CuO nanopowder was produced in a high yield by
adopting ultrasonic in aqueous solution. In our experiment, CuCl2 solution was reacted with NaOH
solution and NaNO2, at ambient conditions applying ultrasonic for 5 min. Precipitation was
performed by varying the molar ratios of NaOH/CuCl2 and NaNO2/CuCl2. CuO nanoparticles of ~ 5
nm and spherical shape were obtained at the NaOH/CuCl2 of 2.0 and the NaNO2/CuCl2 of 0.097.
Without ultrasonication, an amorphous phase was formed at these conditions. This indicates that
sonochemical reaction facilitates direct formation of the nanosized CuO particles. In addition, the
particle morphology varied from sphere through ellipsoid to needle forms depending on pH. In thick
films prepared with the CuO powder for gas sensing, the maximum CO gas sensitivity reached 93 %
at the temperature of 250 °C and depended linearly on CO concentration in log scale over the range of
10 ~ 104 ppm.
Abstract: In this study, FLEC testing skill is tested and examined to validate its applicability to the
emission tests for IAQ. FLEC system has advantages to adapt to in-situ conditions for sampling,
which eases the potential error caused by the distorted test conditions in the lab. The test results from
chamber test and FLEC test are also reviewed in this study and the proper guideline to correlate the
FLECT test result to the chamber test result will be also produced.
Abstract: Thermal conductivity and microstructure of 3YSZ/monazite-type LaPO4 composites
were investigated. Powders were prepared by two kinds of preparation methods such as
conventional ball-milled and chemical precipitation of LaPO4 on the zirconia powder surface.
Thermal conductivity of 3YSZ/monazite-type LaPO4 composites was lower than that of 3YSZ. That
of 3YSZ/monazite-type LaPO4 composites was influenced on the powder preparation methods and
as a function of measured temperature. Microstructure of 3YSZ/monazite-type LaPO4 composites
was not much affected by the amount of dispersed LaPO4 particles. 3YSZ/monazite-type LaPO4
composites were observed to pores after thermal etched. The pore of synthesized specimens was
observed remarkably in compared with conventional ball-milled specimens.
Abstract: The creation of large impervious surface in urban and urbanizing areas have led to
significant impacts on local climate, which is commonly known as urban heat island (UHI). In this
study, porous pavements made of recycled sludge were examined as a way to control UHI by lowering
the surface temperature. A novel image analysis technique was applied to quantify cooling effect of
porous pavement materials without and with water. Although the porous pavement itself has smaller
heat capacity than the natural soil, supplying water to the pavement decreased its surface temperature.
At its highest point, the difference in surface temperatures without and with water was more than 10
oC. The water was supplied either from the top of the pavement or from the bottom of the pavement
using the capillary effects. In both cases, pavement temperature was effectively lowered. The cooling
effect of pavement by surface coating using epoxy-based polymers was negligible because surface
pores were blocked. Field tests also confirmed the cooling potential of porous pavements.