Wayne D. Jennings

Relative Frequency of Ultrasound Diagnoses in Patients Referred for Ophthalmic Ultrasound

An ultrasound diagnostic coding system was developed that permitted entry of diagnoses into a programmable calculator, thus permitting rapid information retrieval of patients with a specific diagnosis or diagnoses as well as the number of patients with a specific diagnosis. Cataract, vitreous opacity, trauma, choroidal disease, and retinal detachment were the most common diagnoses made. Only 7.2% of the patients had a normal ultrasound, indicating that ultrasound examination is a test probably underutilized by ophthalmologists.

Performance and surface analysis of tapered bearings lubricated with a manual transmission fluid

The comparative tribological performance of a series of tapered bearings lubricated with a fully formulated manual transmission fluid (MTF) and its PAO base oil was obtained using a KRL thrust bearing tester. Bearing performance was based on the successful completion of an eight hour test procedure created for the KRL tester. Optical microscopy was used to conduct textural analyses on the body contact areas of tested rollers while X-ray photoelectron spectroscopy (XPS) depth profiles were used to collect surface film composition at the previously mentioned contact area. The KRL results indicated that the MTF operated at lower temperatures and performed better than the PAO. This difference was ascribed to the enhanced thermal stability of the additive packages used in the fluid. The optical analyses detected a series of dark bands at the body contact area of all tested rollers indicative of the presence of an EP/AW surface film. XPS depth profiles of the base oil indicated that it generated a mixture of organic carbon and iron oxide which proved ineffective under more severe test conditions. In contrast, the profile of the MTF included a mixture of carbonate, borate, sulfide, phosphates and oxide throughout the film. Finally, the combination of thermal stability and EP/AW film composition was attributed to the better performance of the MTF.

High Resolution Imaging of Filtered Ultrasonic Echo Responses

Several years ago we developed a high resolution ultrasonic B-scanner for general purpose diagnosis, but specifically oriented for use in ophthalmology.1 In the special case of ophthalmology, high resolution is necessary because of the small size of the eye and the amount of detail required for the diagnosis. High axial resolution (.3mm) was achieved through the use of wideband transducers operating at a nominal frequency of 10MHz. Adequate lateral resolution (approximately 1mm) resulted through the use of focused ultrasonic beams.

High Resolution Instantaneous U1trasonic Spectrum Analysis I: Theoretical Considerations

Several researchers are attempting to use Ultrasonic Spectroscopy as an aid to diagnosis thruugh tissue characterization (1,2) Users of ultrasonic spectroscopy seek to develop ultrasonic tissue signacures or fingerpring spectra of the wide variety of normal and abnormal tissues that can exist in the human body. In addition, fundamental relations between the tissue structure and its ultrasonic frequency response are being sought.