A method is disclosed for directly preparing alkali metal aluminum hydrides such as NaAlH4 and Na3AlH6 from either the alkali metal or its hydride, and aluminum. The guide supports the band in a tilted orientation relative to a dispensing outlet of a liquid dispenser. A user is provided with, based at least in part on the collected information, an indication of relevant data. Moreover, the power supply apparatus sets an initial frequency used when starting to control the output voltage of the piezoelectric transformer to the target voltage, within a frequency range between the two identified frequencies. The data structure contains a pair of pointers, which includes a first pointer to a code to be executed for the compensation function, and a second pointer to a stack frame of a closest lexically enclosing scope of a declaration of the compensation function in a computer program text. The from field may be the \u201cFROM:.