Search | Korea Science

Kim, Deuck-Mo;Mun, Kyung-Ju;Soh, Seung-Young;Soh, Yang-Seob
- Proceedings of the Korea Concrete Institute Conference
- /
- 2008.11a
- /
- pp.669-672
- /
- 2008
bottom ash has difficult in recycling because of low activity and unburned carbon. so our study was control the unburned carbon for improvement of bottom ash. unburned carbon was controlled by distribution. The result of distribution is good that unburned carbon of bottom ash decrease in 4.5%. when we are replace bottom ash with OPC to 10$\sim$30%, specimens strength is decrease. but mix of controlled bottom ash revealed that it's strength increase 6% better than uncontrolled bottom ash.
PDF

성백섭;윤길하;차용훈
- Proceedings of the Korean Society of Machine Tool Engineers Conference
- /
- 2003.04a
- /
- pp.27-32
- /
- 2003
Nanotechnology is the creation and utilization of materials, devices, and systems through the control of matter on the nanometer-length scale, that is, at the level of atoms, molecules, and supramolecular structures. The essence of nanotechnology is the ability to work at these levels to generate larger structures with fundamentally new molecular organization. These nanostructures, made with building blocks understood from first principles, are the smallest human-made objects, and they exhibit novel physical, chemical, and biological properties and phenomena. The aim of nanotechnology is to loam to exploit these properties and efficiently manufacture and employ the structures. Control of matter on the nanoscale already plays an important role in scientific disciplines as diverse as physics, chemistry, materials science, biology, medicine, engineering, and computer simulation. This paper describes the superprecision nano separator to productive particle size of nano powder. this separator system is very important in the industrial area for other high technology parts.
PDF

정인기;박시우
- Journal of Advanced Marine Engineering and Technology
- /
- v.28 no.5
- /
- pp.773-781
- /
- 2004
This research was Performed to raise grade efficiency of Sturtevant type air classifier. to treat powder less than $74\mu\textrm{m}$ particle produced at the crushing process of the dry aggregates manufacturing system or concrete wastes recycling system. The experimental conditions were in the ranges. 0.85 to 5.15 $m^3$/s of primary air flow rate. 0.005 to 0.015 $m^3$/s of secondary air flow rate $30^{\circ}$ to $70^{\circ}$ of auxiliary blades angle. respectively. for 1.7~3.3 kg/min of the powder feed rate. It was found that the grade efficiency of the air classifier was increased as the baffle plate was attached at the expansion region. and the optimal operating conditions of the air flow rates and the blade angle were obtained. The fractional recovery curves from the experiments were well agreement with the theoretical one of Molerus model.
PDF KSCI

여성국;지경락;류정용;신종호;송봉근;서영범
- Journal of Korea Technical Association of The Pulp and Paper Industry
- /
- v.32 no.4
- /
- pp.18-26
- /
- 2000
In order to investigate the influencing factors in flotation fractionation, flotations were performed at varied conditions. The selectivity of fines fractionation was mainly affected by long fiber flocculation degree and if there were not sufficient flocculation of long fibers, more loss of long fibers could not be avoided. The amount of flotation rejects were totally dependent on the stability of froth floated on the stock surface. Only small size fines could stabilize the froth as they hindered the drainage of liquid lamella in flotation-froth. More flotation reject and better flocculation of long fibers were two important factors for improving flotation. Changing a flotation flux or an air-mixing ratio to increase the flocculation of fibers increased long fiber ratio in the reject. In order to satisfy the both conditions of reducing long fiber loss and of increasing flotation reject, search of fractionation promoter is needed.
PDF