BACKGROUND AND PURPOSE The prevalence of facet joint signal change in acute/subacute lumbar vertebral body compression fractures is unknown. We hypothesized that facet joint signal change on MR imaging is more common in facet joints associated with an acute/subacute lumbar compression fracture than those associated with normal vertebral bodies or ones that have a chronic compression fracture. ...

The method of defining quantum joint probabilities of two events is applied to a multimode system of trapped Bose-condensed atoms. The coherent modes are generated by modulating the trapping potential with an alternating field with a frequency in resonance with a transition frequency between two coherent modes. The system is subjected to nondestructive measurements randomly influencing the phas...

Enhanced finite elements are elements with an embedded analytical solution that can capture detailed local fields, enabling more efficient mesh independent finite element analysis. In earlier research, this method was applied to adhesively bonded joints. The adherends were modeled as composite Euler-Bernoulli beams, and the adhesive layer was modeled as a bed of linear shear and normal springs....

Hybrid composite-metal stacks (HCMS) combine metal alloys and composite materials are used in the manufacturing maintenance of aircrafts. Drilling is an important process necessary for installing rivets fuselages. This work sought to identify influence cooled compressed air high-speed cutting (HSC) on drilling multi-material joints with different configurations. Among factors observed type (car...

In this paper a new control strategy is introduced for tip trajectory tracking of flexible-joint manipulators driven by harmonic drives. The proposed controller incorporates friction compensating torque (FCT) and composite controller torque (CCT), which compensate for the friction in the harmonic drives and the flexibility of the joints, respectively. The FCT is a new controller which includes ...

Composite bonded structure is a prevalent portion of today’s aircraft structure. Adequate bond integrity critical aspect fabrication and service, especially since many structural bonds are for flight safety. Over the last decade, non-destructive evaluation techniques have improved but still cannot detect structurally weak that exhibits full adherend/adhesive contact. The result expensive time-c...