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KOCC의 피브릴화 특성 및 라이너판지 물성에 미치는 영향
한준규(Jun Kyu Han),황임정(Im Jeong Hwang),김진모(Jin Mo Kim),최재준(Jae Jun Choi),이용규(Yong Kyu Lee),원종명(Jong Myoung Won) 한국펄프·종이공학회 2018 펄프.종이技術 Vol.50 No.5
Fibrillation was attempted to determine the suitability of KOCC for the production of nanocellulose in order to utilize it as a high value added material, and the possibility of using fibrillated KOCC obtained therefrom as a papermaking additive was evaluated. A grinder was used for the fibrillation of KOCC. In order to investigate the fibrillation characteristics of KOCC, the changes of SEM images, Brookfield viscosity and degree of polymerization were measured. Also, the handsheets were prepared and the changes of major physical properties were investigated in order to evaluate the performance and applicability of fibrillated KOCC as an additive for linerboard manufacture. The fibrillation of KOCC was significantly delayed compared to the bleached chemical pulp, and the complete fibrillation was not achieved, probably due to the residual lignin content (kappa no. 19.36). It is difficult to produce nanocellulose without proper pretreatment. The average fiber length decreased to the level of fines at 20 times of grinding because KOCC was severely aged. As the fibrillation of KOCC proceeded, the degree of Brookfield viscosity continued to increase and the degree of polymerization showed a gradual decrease. Bulk, tear index, and burst index of paper were not significantly affected by the addition of fibrillated KOCC. However, it was found that the tensile index and stiffness could be improved by the combination of retention aid and fibrillated KOCC.
민선식,한준규,권기현,최은동,김문상,Min, Sun-sik,Han, Jun-Kyu,Kwon, Ki Hyun,Choi, Eun-Dong,Kim, Moon-Sang 항공우주시스템공학회 2008 항공우주시스템공학회지 Vol.2 No.2
Aerodynamic characteristics, such as drag and lift, play an important role in automobile design under certain speed conditions. Such characteristics are essential to design an automobile since they are directly related to automobile's performance such as passenger safety and fuel consumption. There is a huge demand for the automobile to have safe performance at high speed. Reduction in drag is also important and it could lead to the solution of air flow induced noise and dust problems. The objective of this research is to find out the aerodynamic differences between conventional side mirror and a modified one using CFD. Although drag generated around a side mirror is only about 7% of the total drag when a car runs, it is very closely related to driver's field of vision and noise generation. CFD simulation of the flowfield around a car side-view mirror was performed using a commercial code; Gambit and FLUENT.