Abstract:
MRI/RF compatible leads include at least one conductor, a respective conductor having at least one segment with a multi-layer stacked coil configuration. The lead can be configured so that the lead heats local tissue less than about 10 degrees Celsius (typically about 5 degrees Celsius or less) or does not heat local tissue when a patient is exposed to target RF frequencies at a peak input SAR of at least about 4 W/kg and/or a whole body average SAR of at least about 2 W/kg. Related leads and methods of fabricating leads are also described.
Abstract:
A device for fatigue testing an implantable medical device having a compression assembly and a first bending assembly. The compression assembly supports first and second portions of the implantable medical device so as to apply a compression force to the implantable medical device along a compression axis and at a compression angle. The first bending assembly is configured to apply a first bending force onto the implantable medical device to move the first portion of the implantable medical device about a first bending axis with respect to the second portion of the implantable medical device. The first bending assembly is coupled with the compression assembly such that the compression angle remains substantially constant regardless of the position of the first portion of the implantable medical device with respect to the second portion of the implantable medical device.
Abstract:
A testing apparatus for a joint includes a support structure for engaging a first part a joint, an adapter for engaging a second part of the joint, a load assembly coupled with the adapter for applying a load onto the adapter and a drive assembly coupled with the adapter. Operation of the drive assembly causes angulation and rotation of the adapter relative to the support structure, which in turn causes angulation and rotation of the first and second parts of the joint relative to one another.
Abstract:
A method is disclosed of using external polymeric analytical techniques to predict in-vivo polymeric performance, more particularly, viscoelastic property characterization for performance modeling of biomedical devices that incorporate a polymeric component and are load-bearing during service. Time-Temperature Superposition can be used to accelerate external testing of pertinent properties. Boltzmann's superposition provides a mathematical methodology for determining the time-dependent strain that develops in response to an imposed stress history. The modeling of the present invention provides an opportunity to describe and predict behavior of the device during in-vivo service, as well as it providing a basis for evaluating alternate “candidate” polymers for use in the construction of the device.
Abstract:
A system for sensing a property of a fluid comprises a fluid channel operable to receive the fluid therein, a flexible arm having a free end positioned within at least a portion of the fluid channel, a fluid actuator disposed sufficiently close to the flexible arm such that actuation of the fluid actuator induces movement of the flexible arm when the fluid is present, and a deflection sensing system operable to quantifiably detect movement of the flexible arm.
Abstract:
A test device for a foldable object is provided. The device comprises a frame, an external balloon and an internal balloon. The external balloon is disposed on the frame, and the internal balloon is disposed on an inner surface of the foldable object. When the internal balloon expands, it provides a first thrust to unfold the foldable object, and when the external balloon expands, it provides a second thrust to fold the foldable object. A folding test on a foldable object is performed accordingly.
Abstract:
An apparatus (10) for testing attachment features (26,28,30,32) of components (12,14) comprises a first member (16) having a first end (18), a second end (20), a first edge (22) and a second edge (24). The first edge (22) has a first firtree slot (26) to receive a first component (12) and the second edge (24) has a second firtree slot (28) to receive a second component (14). The first component (12) has a firtree attachment feature (30) to fit the first slot (26) and the second component (14) has a firtree attachment feature (32) to fit the second slot (28). The first end (18) of the first member (16) has flanges (34,36) extending laterally and the second end (20) of the first member (16) has flanges (38,40) extending laterally such that the first member (16) is substantially H-shaped in cross-section. First load means (42) apply a load on the first component (12) and second load means (44) apply a load on the second component (14) substantially in the opposite direction to the load on the first component (12). The apparatus may be used to test firtree attachments for turbine blades and discs.
Abstract:
A control system for a failure mode testing system is described. The control system employs at least one control algorithm that enables the testing system to be operated at optimal pressure and frequency levels in order to generate a desired system response, such as a desired energy level and desired slope of the fast Fourier transform of the system response. Also described are a pressure dither system and a frequency ringing system for enhancing the operation of the actuator cylinders of the failure mode testing system. All three of the systems can be incorporated, either singularly or in combination, into a computer software program that can be employed to operate and control the failure mode testing system.
Abstract:
A test assembly structure having a first specimen support, a displacement mechanism joined to the first specimen support and a second specimen support. A loading assembly is joined to the second specimen support and configured so as to engage a specimen held by the second specimen support with a specimen held by the first specimen support. A self-reacting structure is joined to the loading assembly having a flexure substantially rigid in the direction of loading of the loading assembly and substantially compliant in the direction of displacement of the displacement mechanism. A second flexure can be configured to support the second specimen support and/or loading assembly on a base. The second flexure is substantially compliant in the direction of loading of the loading assembly and substantially rigid in the direction of displacement of the displacement mechanism.
Abstract:
A method and method of estimating fatigue life of a structure is disclosed. In one embodiment, the method may include determining strain on the structure using a plurality of gauges positioned on the structure. The method may also include detecting a parameter of the structure with a plurality of sensors positioned on the structure. Further, the method includes converting the detected parameter and the determined strain to proportional loads acting on the structure and transforming the proportional loads to coordinate system data associated with the structure. Based on the coordinate system data, the fatigue life of the structure may be estimated.