Owing to a coding error in the electronic source file of this paper, certain expresssions were printed incorrectly. These are corrected at the following places.Page 6, section 2, line 3: βN 1Page 6, section 2, paragraph 2, line 20: 0 m 4Page 8, nine lines above section 3: βN (> 1.5)Page 8, section 3.2, line 8: (6.107 t 6.1083 s)Page 10, section 4.1, lines 4, 5: (κ 1.8) and/or high triangularity (δ 4.5)Page 10, caption of figure 8, last line: (d/a 1.3)Page 11, section 4.2, line 6: d/a 1.3These corrections have been made in the online version.