• The Journal of the Acoustical Society of Korea
• /
• v.35 no.6
• /
• pp.445-451
• /
• 2016

It is very important to obtain non-agglomerated nano particle state for practical application of nano technology. In order to improve the functionality of products using nano particles, more precise control of particle size distribution is required in their synthesis process. However, synthesized nano particles are agglomerated easily due to physical and chemical reasons, and it then veils unique properties of the nano particles and causes some troubles in their practical application. In this study, a separation method for nano particles from suspension by using the droplets as the separation space was proposed. Using the suspension of 0.002 wt. % with $TiO_2$ powder, the particle size distribution of nano particles in the recollected suspension was measured. From the results, it was confirmed that it is possible to separate and to recollect the nano particles monodispersed by using the suggested method.

• Korean Journal of Food Science and Technology
• /
• v.15 no.3
• /
• pp.215-219
• /
• 1983

Rheological properties of the dough made from milled wheat products of various particle size, i.e., wheat shorts, girls and flour, and their effect on the loaf-volume potential of whole wheat bread were investigated in this study. One Korean wheat variety 'Cho-Kwang' was tested for suitability in whole wheat bread. The percent ash and protein content of the milled wheat products were 2.3% and 13.7% respectively. Ranges of 7.3, 5.6 and 4.8 mixograph peak-height were observed in Fraction 1(wheat flours), Fraction 2 (wheat girts) and Fraction 3(wheat shorts), respectively. Dought stability of Fraction 1 did not decreased appreciably as compared to that of commercial first grade baker's flour. Bread-baking test employing a standard formula showed that the wheat grits (0.2-0.5 mm in diameter) appeared to be the limit beyond which a rapid decrease in loaf-volume potential was noted. Optimum loaf volume and crumb characteristics were obtained in 80% wheat grits/20% wheat flour blend.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.22 no.2
• /
• pp.50-56
• /
• 2014

Conventional coagulation-gravity settling processes in heavy metal removal have a problem in coagulant cost and instability of the settling efficiency. The authors investigated the effects of pH and slow mixing conditions on heavy metal hydroxide precipitation and the particle size distribution of the precipitate for a precipitation-membrane separation process. The optimum pH values for the hydroxide precipitation ranged from 9 to 10. The addition of $FeCl_3$ did not enhance the heavy metal removal. 20 min of slow mixing at 70 rpm showed the maximum heavy metal removal to meet the water quality criteria for effluent discharge. More than 99.9% of the heavy metal precipitate particles were bigger than $2{\mu}m$.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.2 no.4
• /
• pp.245-251
• /
• 2004

Soil washing equipment was developed for decontamination of radioactively contaminated soil generated during normal operation or decommissioning and verification experiments were performed. Decontamination effciency above $80{\%}$ was achieved. In case of low radiation level and large particle size, decontamination efficiency was higher. According to the ratio of volume of water to soil quantity, decontamination efficiency was higher in case of high radiation level. Re-decontamination using decontaminated soil was effective in case of small particles. Using soil washing equipment, radioactivity of contaminated soil generated in nuclear power plant can be decreased and volume of soil for disposal can be decreased. And this equipment can be used in decommissioning.

• Resources Recycling
• /
• v.26 no.5
• /
• pp.48-53
• /
• 2017

During steelmaking on EAF, 1 ~ 2% of dust is generated. EAF Dust contains 20 ~ 30% of Zn and Fe. Dust contained in Off-gas is passed through combustion tower and cooling tower, and then captured in bag filter. About 15 wt.% of dust is dropped at the bottom of Combustion tower by its specific gravity, which was also carried out to recycle company with more higher charge than Bag filter dust. This study is focused on the combustion tower dust, and seperation as a function of operation period and particle size. As a result, Zn and Fe content of dust is more affected by size factor than operation period.

• Journal of the Korean GEO-environmental Society
• /
• v.13 no.12
• /
• pp.59-66
• /
• 2012

In this study, it was sampling from heavy metal-contaminated soil with the waste in railroad workshop. And, the pollution concentration and analysis of particle-size distribution were conducted to design efficient purification process that it was aimed at high contaminated area, low contaminated area and samples containing waste foundry sand. But, it was the other signs of general soil contamination, as construction waste of waste concrete and waste wood, waste foundry sand, incinerator ash, etc is overall buried on the grounds. Thus, the common heavy metal purification technology has not decreased the pollution. However, heavy-metal contamination was reduced by magnetic separation utilizing the magnetic component of the mixed waste.

• Resources Recycling
• /
• v.21 no.5
• /
• pp.72-78
• /
• 2012

In general, recyclable items are separately discharged from households and then, hand-sorted into different types of valuables at materials recovery facilities (MRF). However, most of residues after hand-sorting are finally end up with landfill and/or incineration due to lack of separation technologies and economical reasons. In the present study, physical properties on recyclable items obtained from an MRF are investigated to improve the recovery of valuable items. The results of physical compositions based on the sizing tests are also presented.

• Journal of Industrial Technology
• /
• v.24 no.A
• /
• pp.251-261
• /
• 2004

A series of column test with a silty marine soil mixed with Jumunjin Standard Sand were performed to investigate the characteristics of settling and consolidation of non-plastic dredged soils. Column tests were carried out by using the separable column to measure the grain size distribution of consolidated layer. Column tests were performed with changing the mixing ratio of Jumunjin Standard Sand to the silty marine soil, initial water content of slurry and initial height of slurry. Height of interface of slurry was monitored during tests and grain size distribution tests were carried out after finishing tests. Influencing factors on the particle segregation, eventually to the characteristics of settling and consolidation of non-plastic soil, were analyzed on the thesis of test results. As results of column tests, the mixing ratio of sand to the silty marine soil and the initial water content of slurry were known to affect the characteristics of settling and consolidation resulted in significant particle segregation of slurry. Initial height of slurry was found not to affect seriously to particle segregation.

• International Journal of Highway Engineering
• /
• v.14 no.3
• /
• pp.9-14
• /
• 2012

In this study, the profiles of asphalt pavements were measured using a lightweight profiler and depths of macrotexture were analyzed based on the measured profiles. Profiles on dense graded asphalt pavement, prorous asphalt pavement, stone mastic asphalt (SMA) pavement, and base layer measured, and depth of macrotexture were calculated and analyzed. Profiles on the pavement that happened as asphalt mixture segregation were measured and depths of macrotexture were analyzed. The results showed that the depths of macrotexture of asphalt pavement were effectively calculated using the measured profiles, and the depths of macrotexture for different asphalt pavements were analyzed. The pavement areas which have asphalt mixture segregation were detected based on analysis of macrotexture depths.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.469-472
• /
• 2008

As recycled fine aggregate manufacturing technology with exceeding in economical efficiency, reduction efficiency of environmental load and quality improvement effect of recycled fine aggregate, it is to develop dry manufacturing system composed specific gravity separator of high-speed rotation impact type and centrifugal Force Powder Collector, etc. in this study. And it is to verify performance with evaluating quality of recycled fine aggregate. In consequence, it is identify that performance improvement effect of recycled fine aggregate by crushing recycled fine aggregate according to high-speed rotation impact, separating and collecting powder and minuteness dust according to centrifugal Force and mass defect, separating and reclaiming minuteness sand to mass defect.