72 research outputs found

    Design and characterization of a research electrohydraulic lithotripter patterned after the Dornier HM3

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    An electrohydraulic lithotripter has been designed that mimics the behavior of the Dornier HM3 extracorporeal shock wave lithotripter. The key mechanical and electrical properties of a clinical HM3 were measured and a design implemented to replicate these parameters. Three research lithotripters have been constructed on this design and are being used in a multi-institutional, multidisciplinary research program to determine the physical mechanisms of stone fragmentation and tissue damage in shock wave lithotripsy. The acoustic fields of the three research lithotripters and of two clinical Dornier HM3 lithotripters were measured with a PVDF membrane hydrophone. The peak positive pressure, peak negative pressure, pulse duration, and shock rise time of the focal waveforms were compared. Peak positive pressures varied from 25 MPa at a voltage setting of 12 kV to 40 MPa at 24 kV. The magnitude of the peak negative pressure varied from -7 to -12 MPa over the same voltage range. The spatial variations of the peak positive pressure and peak negative pressure were also compared. The focal region, as defined by the full width half maximum of the peak positive pressure, was 60 mm long in the axial direction and 10 mm wide in the lateral direction. The performance of the research lithotripters was found to be consistent at clinical firing rates (up to 3 Hz). The results indicated that pressure fields in the research lithotripters are equivalent to those generated by a clinical HM3 lithotripter

    Plasma Electronics

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    Contains reports on eight research projects.National Science Foundation (Grant G-24073)United States Navy, Office of Naval Research (Contract Nonr-1841(49))Lincoln Laboratory (Purchase Order DDL B-00368)United States ArmyUnited States NavyUnited States Air Force (Contract AF19(604)-7400

    Plasma Electronics

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    Contains reports on eight research projects.National Science Foundation (Grant G-24073)United States Atomic Energy Commission (Contract AF(30-1)-3285)Lincoln Laboratory (Purchase Order DDL BB-107)United States Air Force (Contract AF19(628)-500)United States Atomic Energy Commission (Contract AT(30-1)-3221

    Plasma Electronics

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    Contains reports on nine research projects.National Science Foundation (Grant G-24073)United States NavyUnited States Navy, Office of Naval Research (Contract Nonr-1841(78))United States Air Force (Contract AF19(604)-7400)Lincoln Laboratory (Purchase Order DDL B-00368)United States Arm

    Plasma Electronics

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    Contains reports on nine research projects.U. S. Air Force under Air Force Contract AF 19(604)-7400National Science Foundation under Grant G-9330U.S.Navy(Office of Naval Research)under Contract Nonr-1841(78)U. S. ArmyLincoln Laboratory, Purchase Order DDL B-00337U. S. Nav

    Plasma Electronics

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    Contains reports on twelve research projectsU. S. NavyU.S. Navy (Office of Naval Research) under Contract Nonr-1841(78)U. S. Air Force under Air Force Contract AF 19(604)-7400U. S. ArmyNational Science Foundation (Grant G-24073)Lincoln Laboratory, Purchase Order DDL B-0036

    Plasma Electronics

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    Contains research objectives and reports on six research objectives.National Science Foundation (Grant G-24073)Lincoln Laboratory, Purchase Order DDL BB-107U. S. Air Force under Contract AF 19(628)-50

    Update to Certified Medical Examiners and Screening for Obstructive Sleep Apnea

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