Abstract: Drill bits are provided. The drill bits are of the fixed-cutter, rotary-type. The drill bits have a plurality of blades having cutting elements disposed therealong. Junk slots are formed between the respective blades. A knife opening is formed in at least two of the junk slots. Preferably, the knife openings are disposed substantially transverse to a longitudinal axis of the drill bit. The drill bit also has one or more ribbon cutters. The ribbon cutters cyclically protrude through knife openings in the junk slots in order to facilitate the fragmentation of cuttings ribbons moving through the junk slots during a drilling operation.

Abstract: Drill bits are provided. The drill bits are of the fixed-cutter, rotary-type. The drill bits have a plurality of blades having cutting elements disposed therealong. Junk slots are formed between the respective blades. A knife opening is formed in at least two of the junk slots. Preferably, the knife openings are disposed substantially transverse to a longitudinal axis of the drill bit. The drill bit also has one or more ribbon cutters. The ribbon cutters cyclically protrude through knife openings in the junk slots in order to facilitate the fragmentation of cuttings ribbons moving through the junk slots during a drilling operation.

Abstract: Apparatus and methods for determining thickness and refractive index of thin films and bulk materials are provided. Such apparatus may include a sample support adapted to hold a sample in close contact with the base of a prism, a thermal controller that regulates the temperature of the sample, a light source operable to direct incident light at a variety of incident angles the base of the prism, and a detector positioned to receive output light from the prism. The output light has intensity variations as a function of incident angle. Sample thickness and refractive index may be determined from the intensity variations.

Abstract: Adhesive-backed graphite foil rings (62,64) are suited to forming a seal between a metal gasket plate (12) and adjacent pipe flanges (40, 42). To form the rings, a thin layer of adhesive (74) is applied in the form of a coating to a flexible graphite sheet (70). A release liner (80) may be applied over the adhesive layer. The rings (62,64) are cut from the adhesive coated flexible graphite sheet. In one method, the rings are die cut while leaving the release liner intact. After removal of extraneous material, a plurality of the rings remain attached to the release liner and can be peeled away from the liner as needed. In another method, a central cut-out portion (102) from a large adhesive-backed ring is later used to form a smaller adhesive-backed ring.