Abstract: A subterranean sampling system of the direct push type that employes an elongated push tube in combination with hydraulic means to force the push tube down through subterranean strata includes an improved sampler unit which basically includes a sample retaining cylinder surrounding an elongated slotted tube with a pierce member at the distal end and, at the proximal end, a tube guide member plus an adapter unit by which the sampler unit is connected to the lower end of the push tube. The system enables a new fluid sampling method in which the sampler unit is manipulated by the push tube into three modes. In the first mode, the slotted tube is within the cylinder so none of its slots extend proximally of the cylinder and no ambient fluid can enter. In the second mode, the slotted tube is moved out of the cylinder so only some of its slots extend proximally of the cylinder whereby ambient fluid may enter the cylinder.

Abstract: An orthodontic bracket assembly for bonding to the surface of a tooth is disclosed. The assembly includes a pad and an archwire bracket. A plurality of cavities are provided in the tooth abutting surface of the pad. The walls of the cavities are provided with an irregular surface texture to enhance the bonding between the tooth and the orthodontic bracket. In the preferred embodiment the bracket is cast. The external surface of the bracket is smoothed in a tumbling operation in which the particle size of the abrasive is chosen so that the cavity walls are not subjected to treatment but are left in their irregular, as-cast state. Also disclosed is a method for preparing the mold to produce the cavities in the tooth-abutting surface of the pad.

Abstract: An orthodontic bracket assembly for bonding to the surface of a tooth is disclosed. The assembly includes a pad and an archwire bracket. A plurality of cavities are provided in the tooth abutting surface of the pad. The walls of the cavities are provided with an irregular surface texture to enhance the bonding between the tooth and the orthodontic bracket. In the preferred embodiment the bracket is cast. The external surface of the bracket is smoothed in a tumbling operation in which the particle size of the abrasive is chosen so that the cavity walls are not subjected to treatment but are left in their irregular, as-cast state. Also disclosed is a method for preparing the mold to produce the cavities in the tooth-abutting surface of the pad.