A numerical approach for ventilated disc brake with holes is carried out to investigate the effect of holes on the heat transfer characteristics. The numerical simulation code STAR-CCM+ is utilized to calculate flow and temperature fields with polyhedral meshes. The steady state results show that the holes make the flow velocity on the outer surface increasing, which induce the improvement of convective heat transfer on the outer surface. In the ventilated channel with holes, the convective heat transfer can be reduced due to the inflow of hot air through holes. In unsteady state, the disc has reached the highest temperature in 1,8s since the brake was engaged. The surface of disc without holes has maximum temperatures along the ventilated channels, while the surface temperatures of dis with holes are uniform.

Weed control ís the most ímportant íssue ín organíc farmíng systems that límít crop growth and theír yíeld. Fíeld experíments were conducted ín organíc soybean (Glycine max Merrí/l) to evaluate the weed suppressíon effects of salt and seawater treatment. Weed populatíon and fresh weíght were monítored after 6 weeks of saft and seawater treatments. The most ímportant weeds were Dígítaría sanguínalís, Portulaca oleracea, Tradescantía reflexa and Chenopodíum album var. centrorubrum, but also 6 other specíes were observed ín soybean arable fíeld. Soybean crops under seawater or theír solíds applicatíon were well grown. The results treated wíth salts and seawater índícate decreases by 13.4-30.8% ín weed densíty and by 18.0-43.2% ín theír fresh weíght and soíl hardness íncreases of up to 2.1-fold. Salt and seawater províded good addítíonal weed control, but they were caused a seríous problem ín deteríoratíon of soíl physícal propertíes.