PURPOSE To determine the effect of multiple autoclave sterilization cycles on the integrity of titanium plates and screws used in craniofacial reconstruction. MATERIALS AND METHODS Torque to fracture was evaluated for 36 titanium 6AL-4V (Ti 6/4) screws divided evenly into 3 groups and tested as machined (control), after 10 cycles of autoclaving or after 50 cycles of autoclaving. Sterilization...

A control system describing the dynamics of a rotating Timoshenko beam is considered. We assume that the beam is driven by a control torque at one of its ends, and the other end carries a rigid body as a load. The model considered takes into account the longitudinal, vertical, and shear motions of the beam. For this distributed parameter system, we construct a family of Galerkin approximations ...

This paper reports the design, installation and testing of a set of multilayer confocal mirrors in a side-by-side arrangement, built to increase the intensity from a molybdenum rotating-anode X-ray source. Ray-tracing experiments were performed in order to evaluate the best design parameters for the system, which are shown to be a side-by-side configuration of 100 mm length. Measurements of the...

Considered is the control and stabilizability of a slowly rotating non-homogeneous Timoshenko beam with the aid of a torque. It turns out that the beam is (approximately) controllable with the aid of the torque if and only if it is (approximately) controllable. However, the controllability problem appears to be a side-effect while studying the stabilizability. To build a stabilizing control one...

Figure 1 gives an overview of the configuration for production of pions by a proton beam impinging on a long, thin target, followed by capture of low-momentum, forward pions in a channel of solenoid magnets with rf cavities to compress the bunch energy while letting the bunch length grow, thus rotating the bunch in phase space. This configuration was conceived for a muon collider [2, 3] with a ...

New fan-beam DXA systems can detect vertebral fractures with fast, low-dose lateral scans of the vertebra from T4 to L4 in as little as 10 seconds. Vertebral fractures are the most common fracture in osteoporosis and an indication for treatment irrespective of Bone Mineral Density [1-3]. However, without a diagnostic test such as that available on fan-beam DXA systems, as many as 75% of vertebr...

We evaluate the Liénard-Wiechert field of a rotating superluminal point source numerically and show that this radiation field has the following intrinsic characteristics. (i) It is sharply focused along a narrow, rigidly rotating spiral-shaped beam that embodies the cusp of the envelope of the emitted wave fronts. (ii) It consists of either one or three concurrent polarization modes (depending ...

A new type of rotating anticathode X-ray generator has been developed, in which the electron beam irradiates the inner surface of a U-shaped anticathode (Cu). A high-flux electron beam is focused on the inner surface by optimizing the shape of the bending magnet. The power of the electron beam can be increased to the point at which the irradiated part of the inner surface is melted, because a s...

We show that superlattices can be formed in the ternary and quaternary ln(GaAl)As alloys on InP by molecular beam epitaxy without mechanical shuttering. Periodic ordering is produced by rotation of the substrate through the naturally nonuniform distribution of beam fluxes at the rotating substrate. The growth rate and substrate rotation rate together determine the superlattice period which is m...

We study the maximum temperature rise induced by a rotating or dithering Gaussian laser beam on a two-layer body. First, we derive semi-analytical solutions by solving the transient threedimensional heat equation in a semi-infinite domain with insulating surface. Second, we provide numerical solutions for a two-layer structure in a finite domain. Our results show that the maximum temperature ri...