This experiment was carried out to compare the effects of feeding commercial formula feed and rice straw separately (control) versus a total mixed ration (TMR) on productivity of Hanwoo steers in late stage of fattening and on ruminal fermentation characteristics and digestibilities. Ruminal digesta from the cannulated cattle were sampled at 0, 1, 2, 3, 5, 8 hour after feeding.The steers fed TMR consumed 7.4kg per day and there was no difference between feeding systems. Daily weight gain was not significantly (P>0.05) between feeding systems, however, TMR group showed lower daily gain than control group. The amount of feed consumption per kg weight gain was higher in TMR group than control group (10.5kg and 9.7kg, respectively), resulting in a greater efficiency of feed utilization for gain. In the result of appearance rates of quality grade A were 33% higher for TMR group than those in control group. Appearance rates of grade 1 showed 56% and 75% when fed the control and TMR, respectively.Digestibilities of dry matter, crude protein, crude fiber and gross energy for TMR treatment were significantly higher (P<0.01) than those of control. Prior to feeding (0 h) and each subsequent hour, the TMR resulted in higher rumen pH (P<0.05) when compared with control ration. The concentration of NH3-N for TMR treatment maintained at higher level up to 8hr after feeding, especially increased up to 28.2mg/ during 1 2 hour which was two times (P<0.05) more than control. The amount of total VFA showed same trends between feeding systems. However, the ratios of branched chained fatty acid such as iso-butyric acid and iso-valeric acid for TMR treatment were significantly(P<0.01) higher than control for 3 5hr. Results showed that TMR in these trials is effective feeding system for fattening Hanwoo steers in the respect of ruminal characteristics, total tract digestibility and productivities.

This study has analyzed the effect of noise sources of power seat slide adjuster on sound quality and human sensitivity through statistical methods. First, sound quality analysis using sound quality metrics was performed to analyze objective data. Next, the subjective evaluation of sound quality was performed by a jury test. There were two types of sound sources used for the jury test; one was two original sounds measured in the operating test and the other one was eight virtual sound sources that were produced by amplifying a specific frequency of original sounds. It was designed to derive the causal relationship between each noise source and human sensitivity. Thirdly, we analyzed the correlation between the sound quality metrics and the sound pressure level of the noise source through the factor analysis. As a result, four independent variables were derived. Lastly, stepwise regression analysis was performed using four independent variables and the results of the jury test. The derived regression models had considerable explanatory power. From this, it was possible to understand the influence of the noise source of the seat slide adjuster on the sound quality and human sensitivity.

Heat pipes have been recently in use for cooling purposes in various fields, including electronic circuit boards and vehicle parts that generate large amounts of heat. In order to minimize the loss of heat transferred, there is a need to maximize the contact area of the working fluid. This study produced a square tube multi-channel heat pipe to replace the existing circular pipe type to maximize the internal surface area thereof. This expands the surface, allowing the working fluid to come into contact with a wider area and enhancing thermal radiation performance. A mold for the production for such a product was designed, and finite element simulation was performed to determine whether production is possible.

This paper performed a numerical analysis study of the cutting characteristics when drilling a taper hole whose upper and lower diameters are different, that is, a pilot hole. 3-dimensional drilling analysis was performed using a commercial code, and these results were used to determine analytically and compare the cutting temperature, the phenomenon of cutting chip formation, deformation and pressure, etc., for the tools, chips, and specimens during cutting. Also, cutting force and the required energy were calculated and compared. To verify the results of analysis, a cutting dynamometer was used to analyze 3-axis cutting force. Results of analysis showed that the specimen maintained a temperature of approximately 650• , with rapid cooling after chips were formed from the specimen. The tool reached a maximum of 700• , similarly to the chips. It is expected that these results will be utilized to optimize cutting processes and work conditions when drilling holes.