A thermoplastic molding composition that features good mechanical properties as well as processability is disclosed. The interior space within the sealed foil is evacuated and charged with sufficient water to saturate the wick through a copper tube which is then hermetically sealed, producing the working core of a flat plate heat pipe. Each reference memory cell may store a reference bit and each packet of m memory cells may store m bits of the associated block, when m is greater than 1, with different parities.