A first attachment portion has a first closed aperture defining a circular ring portion that extends over a first circumferential range of at least 180 degrees of arc that is symmetrically disposed relative to an axis. The current DAC is configured with individual column decoders for even and odd rows of current unit cells, thus allowing for independent control of adjacent rows. A service element providing a complete function is a service offering. The present invention further relates to a process for preparing the catalysts detailed above and to a process for preparing carboxamides by reacting carbonitriles with water in the presence of the present catalyst.