• International Journal of Highway Engineering
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• v.10 no.2
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• pp.183-191
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• 2008

This study evaluated influence of the loading head dimension on characteristics of deformation strength ($S_D$) of asphalt mixtures. Kim test and Wheel tracking (WT) test were conducted to evaluate $S_D$ characteristics with relation to WT results for various mixtures. The $S_D$ values and coefficient of variation of $S_D$ values of r=10mm were smaller than those of r=10.5mm. It was also found that $S_D$ values obtained using r=10mm loading head showed high correlations with rut parameters of WT test. It was indicated that the aggregate size and radius (r) of round cut were statistically significant variables on $S_D$ at = 0.05 level in the analysis of variance. However, in interaction of r and aggregate size showed no significance within $10{\sim}19mm$ aggregate size at the same level. Therefore, it was concluded that the diameter (D) of 40mm and the bottom edge radius (r) of 10mm was suitable dimension of loading head for deformation strength test.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.2
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• pp.87-96
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• 1995

The cutting force is the most important variable to understand the mechanics of ultra-precision machining. Most dynamometers, however, monitor the static cutting force only. But it is necessary to measure the dynamic cutting force to clarify the machinability of the material, the formation of the chip, chatter and the wear of the tool. In this research, measurement of the dynamic cutting force in order to clarify the machin-ability of the material, the formation of the chip, chatter and the wear of the tool has been conducted. A combined-type dynamometer which could measure the static cutting force and the dynamic cutting force by use of strain gauges and a piezo-film accelerometer has been developed. An analysis of the dynamometer also has been carried out.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.23-24
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• 2013

• Journal of the Korean Wood Science and Technology
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• v.8 no.2
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• pp.6-8
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• 1980

Japanese larch veneer, Cryptomeria veneer and japanese cypress veneer were peeled with condition of nose bar pressure at 5%, 10%, 15%, to find the optimum nose bar pressure. 1. Optimum nose bar pressure was 15% in 2mm thickness veneer of japanese larch. 2. Optimum nose bar pressure was 5% in 2mm thickness veneer of Cryptomeria. 3. Optimum nose bar pressure was 15% in 2mm thickness veneer of japanese cypress.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1654-1660
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• 2009

Two different cutting-oils from H and B companies which are sold as an eco-friendly cutting-oils were selected and the biodegradability of these commercially available cutting-oils was evaluated by the sequencing batch reactor (SBR) processes. The cutting-oil wastes ($H_1$) pre-treated by coagulation/flocculation was used as an influent to SBR. When the F/M ratio was operated 0.04 to 0.08kgCOD/kgMLSS d, removals of $BOD_5$and $COD_{Cr}$were above 97% and 91%, respectively. T-N and T-P removals were above 76% and 81%, respectively. If the diluted cutting-oil wastes ($B_1$) was used as an influent of the SBR, $COD_{Cr}$removals were above 77% at the F/M ratio of 0.01-0.02kgCOD/kgMLSS d. After the cutting-oil wastes was treated by coagulation/ flocculation ($B_2$), $COD_{Cr}$removals was above 85%. If the pre-treated cutting-oil wastes were mixed with a synthetic wastewater ($B_3$) and fed into the SBR in order to mimic the real wastewater treatment plant situation, $BOD_5$and $COD_{Cr}$removals were above 97%, 91%, respectively. T-N and T-P removals were above 79% and 76%. The ratio between $BOD_5$and $COD_{Cr}$, ($COD_{Cr}$-$BOD_5$)/$COD_{Cr}$, indicating the biodegradability of effluent of the SBR, was calculated to 85% and 61%. This means that significant amounts of non-readily-biodegradable organic compounds in the effluent of $H_1$, $B_3$are still present.

• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.2
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• pp.139-152
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• 2008

A series of numerical experiments were carried out to simulate the rock cutting behavior by TBM disc cutter in a given took condition. AUTODYN-3D, a commercial program capable of simulating three-dimensional dynamic failure, was utilized to carry out the numerical tests over four different disc cutter spacing conditions. After modelling three-dimensional geometries of disc cutter and rock specimen, the linear cutting tests by a disc cutter were simulated for eight different types of rocks. The numerical result, that is the optimum cutter spacing for isotropic rocks had the good agreements with those from linear cutting test. However, for relatively anisotropic or jointed rocks, the specific energy obtained from the numerical tests was almost two-times bigger than the real linear cutting results. Therefore, to simulate cutting procedures for anisotropic rocks realistically, further studies would be necessary.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.5 no.1
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• pp.79-83
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• 2001

We find a cutting formula of the Diamond wheel with two radii.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.02a
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• pp.231-238
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• 2002

미세 절삭에 의한 마이크로 형상가공 및 이를 이용한 미세금형 가공기술개발을 위하여 절삭 공구를 이용한 기계적 미세 가공법에 대한 고찰과 더불어 shaping, end-milling, drilling 등의 가공이 가능한 기계적 미세 가공시스템을 구성하고 이를 이용한 미세 치형 그루브와 미세 격벽 등 미세 형상 구조의 금형 개발을 위한 가공실험을 수행하였다. 본 실험에서는 먼저 shaping 방식으로 세 종류의 다이아몬드 바이트를 사용하여 알루미늄, PMMA, Nickel, 황동 등의 소재에 pitch $150{\mu}m$, 높이 $8{\mu}m$ 내외의 미세 치형의 금형 코어를 가공하였고, 다음으로 Z축에 air spindle을 설치하여 $\phi0.2mm$의 end-mill(WC)을 사용하여 황동 소재에 깊이 $200{\mu}m$, 폭 $200{\mu}m,\;100{\mu}m,\;50{\mu}m,\;30{\mu}m$의 두께 변화를 주어 미세 격벽에 대한 가공실험을 하였다. 미세 구멍가공실험으로는 drilling 전용장비를 구성하여 $\phi0.6\~0.15mm$의 drill공구로 SM45C와 세라믹$(Si_3N_4-BN)$ 소재에 스텝이송방식에 의한 미세 구멍 가공 실험을 실시하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.1000-1003
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• 2001

This paper presents the numerical analysis and experimental verification to know the metal cutting burr formation mechanism in face milling operation. Finite element method are applied to predict the 2-D burr formation process prediction. Face milling process are adjusted to analyze the characteristics of burr shapes according to various cutting conditions. The cutting parameters were investigated with cutting speed, feed rate, depth of cut. Through the experiments various burr types are classified according to its shape and properties.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.347-350
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• 2003

Many researches on the prediction of cutting forces of ball-end mil is have been achieved since before several decades ago. These kinds of researches have been concentrated on the study on how to make the prediction equations for the cutting forces based on 2-D cutting experimentation. The results of them were really good and impressive. But it's not proper to practical uses for industrial fields, because if sculptured surface were to be machined, then it would be very difficult to understand the complicated kinematical interaction between the sculptured surface and the flutes of a ball-end mill. So, we propose the method for solving these kind of problems using existed commercial CAD/CAM software; Unigraphics. Furthermore, the modification of tool path which is done off line is offered to increase the precision of cutting.