A customer illumination aperture structure for lithographic exposure is disclosed, including a central part and at least one off-axis part around the central part. The apparatus comprises a break-in head that is removably attached to a drive shaft to which a polishing head that holds the semiconductor wafer is normally attached. Various methods for directly determining the progress of erosion of an airfoil of a turbine blade are also provided. Each energy-absorbing, head-impact mechanism absorbs energy of an impact with its associated headliner by a passenger of the vehicle. The valve is displaceable by pressing the ends between a closed configuration in which the pistons block liquid from the cavity from entering the interstitial space, and a dispensing configuration in which the interstitial space is aligned with the passage and the spout to allow liquid from the cavity to reach the spout. In particular, the present invention is directed to herbicidal compositions or formulations, as well as their methods of use, which comprise N-phosphonomethylglycine or a herbicidal derivative thereof, a pyridine analog or a herbicidal derivative thereof, and optionally one or more suitable surfactants, with N-phosphonomethylglycine being in excess relative to the pyridine analog.