The experimental data from the central composite design runs were utilized for mathematical models far the drilling characteristics containing linear, quadratic and interactive effects of the parameters such as volume fraction of TiC in the composites, drill speed, feed rate and drill diameter. The models were developed via stepwise selection where the insignificant effects were removed using t-test. The models were subjected to optimization of maximizing drill life and satisfying the other constraints.

[ ] alloys with Al, B or Nb were prepared by an advanced consolidation process that combined mechanical alloying with pulse discharge sintering (complex forming) to improve the mechanical properties. Their microstructure and mechanical properties were investigated. The alloys fabricated by complex forming method showed very fine microstructure when compared with the sample sintered from commercial powders. Alloys made from powders milled in Ar gas had fewer silica or alumina phases as compared to their counterparts sintered from powders milled in air. In densification of the sintered body, addition of B was more effective than Al or Nb. Both Victors hardness and tensile test indicated that the alloy fabricated by the complex forming method showed better properties than the sample sintered from commercial powders. The Al added alloy sintered from the powders milled in air had the superior mechanical properties due to the suppression of and formation of fine particles.

The VOCs discharge characteristics of miscellaneous assembly metal manufacture & metal processing industries, in the SihwaㆍBanwol Industrial Complex, were analyzed according to detailed categories per industry, as based on the Korea Standard Industrial Classification, by comparing the conditions before and after the installation of process and prevention facilities. The average concentration of benzene was highest in the metal heat treatment industry (28921) whereas that of toluene was highest in the painting & membrane treatment industry (28923). In addition, with respect to prevention facilities, our evaluation proved that the decreased efficiency was worse for the discharge facilities of pollutants from the plating industry (28922) and painting & miscellaneous membrane treatment industry (28923), with some exceptions, while most facilities showed no decreased efficiency. Therefore, it is believed that an accurate survey of the conditions of administration/operation facilities will need to be conducted, and the decreased efficiency will also need to be evaluated so that adequate prevention facilities can be reviewed and selected.