• Journal of the Korean Wood Science and Technology
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• v.49 no.4
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• pp.328-335
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• 2021

Considerable differences exist in the characteristics of size reduction and classification because of biomass species. Miscanthus sacchariflorus (M. sacchariflorus) Goedae-Uksae 1 is not used efficiently because of the imperfections of the processing technology for this biomass. Therefore, for the best use of specific biomass, improvement in the feedstock preparation of the biomass for processing, such as pellet manufacturing, is necessary. In this study, a laboratory-scale cone grinder and air classifier were designed and combined to investigate the performance of the combination system for M. sacchariflorus. The average equivalent spherical diameter of particles showed a close relationship with air velocity for air classification. The air velocity range to classify proper particles for pelletization was determined to be 6.0-6.8 m/s. The mass ratios of the collected particles to feed mass for four lengths of chopped M. sacchariflorus were 45.1%:46.1%, 39.1%:46.6%, and 44.1%:52.8% at the first, second, and third steps in simulating the multistep combination system, respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.79-83
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• 2001

A cone-shaped active magnetic bearing spindle system for high speed internal grinding is designed and tested. The cone-shaped AMB system consists of only 4 couples of magnet, it can be smaller and lighter than conventional radial-axial-type AMB system. In this paper, the cone-shaped electromagnets are designed by magnetic circuit theory, and de-coupled direct feedback PID controller is applied to control the coupled magnetic bearings. The designed cone-shaped AMB spindle system is built and constructed with a digital control system, and tested its stbility and dynamic performances. As the results of the tests, this spindle runs up to 40,000 rpm with about 5 ${\mu}{\textrm}{m}$ of runout, and the AMB system provides high damping ratio eliminating overshoot and resonance speed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.261-262
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• 2018

In this study, the quality of recycled aggregate for concrete was investigated as the number of recycled aggregate crushing cycles, grinder and crusher, peeling and crushing. First, the quality of density, absorption ratio and solid content was improved as the separation distance decreased and the number of crushing increased, depending on the number of crushing of recycled aggregate and the distance between mantle and cone cave. The quality of density, absorption ratio and solid content was improved as the wire mesh used in striking plate and the number of hammers increased, depending on the type of striking plate and the number of hammers.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.2
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• pp.121-129
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• 2017

In this study, the quality of recycled aggregate for concrete was investigated as the number of recycled aggregate crushing cycles, grinder and crusher, peeling and crushing. First, the quality of density, absorption ratio and solid content was improved as the separation distance decreased and the number of crushing increased, depending on the number of crushing of recycled aggregate and the distance between mantle and cone cave. The quality of density, absorption ratio and solid content was improved as the wire mesh used in striking plate and the number of hammers increased, depending on the type of striking plate and the number of hammers.