Abstract: A method and apparatus implementing the method, which is not dependent on monitoring the electrical impedance of the lead, detects imminent structural failure of an electrical lead in an implanted medical device, such as an implantable cardioverter-defibrillator (ICD) or a pacemaker. The approach is to monitor directly the mechanical load loss of the lead (a measure of the loss of structural integrity of the lead) rather than, as in the prior art, to infer it from the electrical impedance.

Abstract: In a method and apparatus for detecting a crack in a human tooth, especially one covered by a restoration, such as a crown, the approach is to stress the suspect tooth and, by means of acoustic emission techniques, analyze the characteristics of the resultant acoustic emission from the tooth. To aid the identification of a crack from the acoustic emission signal, a baseline may be obtained by performing this procedure at a time when the tooth is known not be cracked, e.g., when a restoration is placed on it. This baseline acoustic emission signature is recorded. This procedure is repeated at intervals. The subsequent measurements are compared with the baseline to identify changes that indicate the initiation and growth of a crack. The invention includes apparatus for implementing the method. The approach is to integrate the acoustic emission pulser and sensor into commercially available dental instruments, e.g., a tooth polisher and a water syringe.

Abstract: A method and apparatus implementing the method, which is not dependent on monitoring the electrical impedance of the lead, detects imminent structural failure of an electrical lead in an implanted medical device, such as an implantable cardioverter-defibrillator (ICD) or a pacemaker. The approach is to monitor directly the mechanical load loss of the lead (a measure of the loss of structural integrity of the lead) rather than, as in the prior art, to infer it from the electrical impedance.

Abstract: A method and apparatus implementing the method, which is not dependent on monitoring the electrical impedance of the lead, detects imminent structural failure of an electrical lead in an implanted medical device, such as an implantable cardioverter-defibrillator (ICD) or a pacemaker. The approach is to monitor directly the mechanical load loss of the lead (a measure of the loss of structural integrity of the lead) rather than, as in the prior art, to infer it from the electrical impedance.

Abstract: In a method and apparatus for detecting a crack in a human tooth, especially one covered by a restoration, such as a crown, the approach is to stress the suspect tooth and, by means of acoustic emission techniques, analyze the characteristics of the resultant acoustic emission from the tooth. To aid the identification of a crack from the acoustic emission signal, a baseline may be obtained by performing this procedure at a time when the tooth is known not be cracked, e.g., when a restoration is placed on it. This baseline acoustic emission signature is recorded. This procedure is repeated at intervals. The subsequent measurements are compared with the baseline to identify changes that indicate the initiation and growth of a crack. The invention includes apparatus for implementing the method. The approach is to integrate the acoustic emission pulser and sensor into commercially available dental instruments, e.g., a tooth polisher and a water syringe.

Abstract: A method and apparatus implementing the method, which is not dependent on monitoring the electrical impedance of the lead, detects imminent structural failure of an electrical lead in an implanted medical device, such as an implantable cardioverter-defibrillator (ICD) or a pacemaker. The approach is to monitor directly the mechanical load loss of the lead (a measure of the loss of structural integrity of the lead) rather than, as in the prior art, to infer it from the electrical impedance.

Abstract: A low-cost, multi-axis, quasi-random vibration system includes pneumatically driven vibrators coupled to a resonating, self-attenuating shaker structure to achieve a frequency spectrum and acceleration-level control of a broadband quasi-random vibration output in the frequency range, for example, from 40 Hz to 2 kHz for vibration testing of equipment. The shaker structure consists of flexible interconnected structures whose primary or driving structure acts to mechanically process the vibratory input of the coupled vibrators and whose supporting or driven structure supplies a further vibrational processing to supply the test item with multi-axis multimodal input. Automatic control and pseudo-random modulation of air pressure of the pneumatic vibrators provide closed-loop broadband acceleration-spectrum control and spectrum smearing to enhance frequency content and to prevent the shaker from locking onto any particular vibration frequency, especially a natural frequency of the shaker.

Abstract: A high power, cw, high pressure, electrically excited flowing gas laser is disclosed wherein a laser excitation transverse to the direction of gas flow is initiated by a uniform electron beam perpendicular to the gas flow direction. Laser gas supplied to a plenum chamber at a pressure substantially greater than atmospheric pressure is conditioned by a perforated plate nozzle to flow through the laser cavity in a uniform stream at the desired subsonic velocity. A variable angle diffuser is provided downstream from the laser cavity to decelerate and compress the laser gas before exhausting it into the ambient atmosphere such that at the downstream end of the laser excitation region the laser gas is maintained at a pressure slightly lower than atmospheric pressure.

Abstract: A subsonic flow aerodynamic window in a high energy gas laser, which seals off the laser optical cavity from the ambient gas, while minimizing the degradation of the laser output beam. Since the flow of the aerodynamic window is subsonic, gas consumption and degradation of the laser output beam are minimized.