A white solid was precipitated when ozone was introduced into the solution containing Al2 (SO4) 3 (NH4) 2SO4·24 H2O as the starting material. When ozone was introduced, pH of the solution decreased. The solid was identified as β-Al203.31120 by X-ray diffraction analysis. The transition energy 4H from β-Al203.3 H2O to 77-Al203 was determined using commercial β-Al2O3·3H2O (i) and β-Al2O3·3H2O (ii) obtained in this study. The ΔH determined were about 23. 3 mcal/ mg for (i) and 21.3 mcal/mg for (ii), respectively. Grain size distribution was determined, and the grain size of β-Al2O3·3H2O (ii) was in the range of 0.3μm to 4. 0 μm. The grain having 0.3μm occupied about 30% and this distribution pattern in compared with the starting material did not change even they were calcined at the temperatures for production of η-or α-Al2O3.
Measurements of the drag (Fη) of brush and pressure (Fυ) applied on it of Newtonian fluid have been quantitatively made under various brushing conditions using an apparatus consisting of a reciprocator, two-dimensional dynamometer and others. The equations derived to correlate Fη, and Fυ with rheological properties of paints were discussed with these results, and it is concluded that Fη and Fυcould be expressed by Fη=a1 A·η·υ/h+b1 (_??_α1>0) Fυ=a2 B·η·υ/h2+b2 (_??_ α2<0) or Fυ=a3α3A·η·υ/h+b3 (_??_α3<0) where A is contact area of brush, B is brush width, η is viscosity of fluid, υ is brush speed, h is wet film thickness, a's are correcting coefficients and b's are constants concerning the horizontal and vertical components of the initial forces applied on brush to bend.