Structural characterization of a first-generation articulated-truss joint for space crane application

A first-generation space crane articulated-truss joint was statically and dynamically characterized in a configuration that approximated an operational environment. The articulated-truss joint was integrated into a test-bed for structural characterization. Static characterization was performed by applying known loads and measuring the corresponding deflections to obtain load-deflection curves. Dynamic characterization was performed using modal testing to experimentally determine the first six mode shapes, frequencies, and modal damping values. Static and dynamic characteristics were also determined for a reference truss that served as a characterization baseline. Load-deflection curves and experimental frequency response functions are presented for the reference truss and the articulated-truss joint mounted in the test-bed. The static and dynamic experimental results are compared with analytical predictions obtained from finite element analyses. Load-deflection response is also presented for one of the linear actuators used in the articulated-truss joint. Finally, an assessment is presented for the predictability of the truss hardware used in the reference truss and articulated-truss joint based upon hardware stiffness properties that were previously obtained during the Precision Segmented Reflector (PSR) Technology Development Program

Paravertebral block: anatomy and relevant safety issues.

Paravertebral block, especially thoracic paravertebral block, is an effective regional anesthetic technique that can provide significant analgesia for numerous surgical procedures, including breast surgery, pulmonary surgery, and herniorrhaphy. The technique, although straightforward, is not devoid of potential adverse effects. Proper anatomic knowledge and adequate technique may help decrease the risk of these effects. In this brief discourse, we discuss the anatomy and technical aspects of paravertebral blocks and emphasize the importance of appropriate needle manipulation in order to minimize the risk of complications. We propose that, when using a landmark-based approach, limiting medial and lateral needle orientation and implementing caudal (rather than cephalad) needle redirection may provide an extra margin of safety when performing this technique. Likewise, recognizing a target that is not in close proximity to the neurovascular bundle when using ultrasound guidance may be beneficial

11. SUPPLEMENTARY NOTES 5. FUNDING NUMBERS

OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of thi

Structural Characterization of a First-Generation Articulated-Truss Joint for . . .

(Maximum 200 words) A first-generation space crane articulated-truss joint was statically and dynamically characterized in a configuration that approximated an operational environment. The articulated-truss joint was integrated into a test-bed for structural characterization. Static characterization was performed by applying known loads and measuring the corresponding deflections to obtain load-deflection curves. Dynamic characterization was performed using modal testing to experimentally determine the first six mode shapes, frequencies, and modal damping values. Static and dynamic characteristics were also determined for a reference truss that served as a characterization baseline. Load-deflection curves and experimental frequency response functions are presented for the reference truss and the articulated-truss joint mounted in the test-bed. The static and dynamic experimental results are compared with analytical predictions obtained from finite element analyses. Load-deflection res..