Abstract: A mud pulser for measurement-while-drilling applications is disclosed which employs piezoelectric transducers to provide for variations in the mud flow through a mud pulser sleeve. The piezoelectric transducers used in the mud pulser are comprised of two piezoelectric elements bonded together in a bender bar transducer configuration, thin metallic sheets to improve the rigidity of the transducer and to protect the ceramic material and electrodes from the effects of abrasive drilling fluid, and simplified mounting means.

Abstract: A tubewave damper probe for the suppression of borehole tubewaves in seismic applications is disclosed. The damper probe is suspended into a borehole by means of a cable and is comprised of a housing, a gas-filled bladder within the housing, and a plurality of valves located on the housing. The damper probe operation is based on a modified Helmholtz resonator effect. The bladder is precharged before insertion into the borehole, and pressure variations within the borehole cause the bladder to expand or contract. The valves are designed such that expansion of the bladder causes the valves to close, and contraction of the bladder causes the valves to open. The valves also prevent over-expansion of the bladder.

Abstract: A analytic bone implant includes a cylindrical housing with an inner chamber designed for collecting sample of bone tissues. The outer surface of the housing is provided with a plurality of threads for securing the implant into bone tissue. The housing is further provided with a plurality of openings to allow new bone tissue to grow into a collecting basket. The openings in the housing are alignable with complementary openings in the basket. The openings on the basket are provided with sharp edges which serve as cutting blades to facilitate the removal of the bone sample. The implant includes provision for repeated access to the medullary compartment for obtaining sample of cancellous tissue for histologic and morphometric analysis.