Nuclear thermionic converter

Efficient nuclear reactor thermionic converter units are described which can be constructed at low cost and assembled in a reactor which requires a minimum of fuel. Each converter unit utilizes an emitter rod with a fluted exterior, several fuel passages located in the bulges that are formed in the rod between the flutes, and a collector receiving passage formed through the center of the rod. An array of rods is closely packed in an interfitting arrangement, with the bulges of the rods received in the recesses formed between the bulges of other rods, thereby closely packing the nuclear fuel. The rods are constructed of a mixture of tungsten and thorium oxide to provide high power output, high efficiency, high strength, and good machinability

Results of an experimental program to provide low cost computer searches of the NASA information file to university graduate students in the southeast Final report

Experimental program to provide low cost computer searches of NASA information files to university graduate student

Generalised photon sieves: fine control of complex fields with simple pinhole arrays

Spatial shaping of light beams has led to numerous new applications in fields such as imaging, optical communication, and micromanipulation. However, structured radiation is less well explored beyond visible optics, where methods for shaping fields are more limited. Binary amplitude filters are often used in these regimes and one such example is a photon sieve consisting of an arrangement of pinholes, the positioning of which can tightly focus incident radiation. Here, we describe a method to design generalized photon sieves: arrays of pinholes that generate arbitrary structured complex fields at their foci. We experimentally demonstrate this approach by the production of Airy and Bessel beams, and Laguerre–Gaussian and Hermite–Gaussian modes. We quantify the beam fidelity and photon sieve efficiency, and also demonstrate control over additional unwanted diffraction orders and the incorporation of aberration correction. The fact that these photon sieves are robust and simple to construct will be useful for the shaping of short- or long-wavelength radiation and eases the fabrication challenges set by more intricately patterned binary amplitude masks

Medical implantable devices for the controlled release of anti-TGF-beta1 in the repair of peripheral nerve injuries

The development of novel bioartificial nerve grafts which release soluble therapeutic agents, shows great promises guiding the extension of the injured axons and optimizing and improving the degree and specificity of neural outgrowth. The TGF-â family cytokines are polypeptides involved in pathogenesis of neuropathies during nerve lesion. In particular, studies carried out on TGF-â1 have demonstrated its key-role as a humoral stimulus in scar formation. The use of neutralising antibodies to this pro-fibrotic factor, incorporated and released by medical devices, could be potentially useful to get improved results in nerve repair. The aim of this study was to characterise the uptake and release of antibodies, structurally no different from the anti-TGFâ1 specific ones, by innovative constructs based on the use of biodegradable and biocompatible compounds with which to support and improve peripheral nerve repair

Sterilization of liquids by filtration and certification of probability

Sterilization of liquids by hydrosol filtratio

Observation of persistent flow of a Bose-Einstein condensate in a toroidal trap

We have observed the persistent flow of Bose-condensed atoms in a toroidal trap. The flow persists without decay for up to 10 s, limited only by experimental factors such as drift and trap lifetime. The quantized rotation was initiated by transferring one unit, $\hbar$, of the orbital angular momentum from Laguerre-Gaussian photons to each atom. Stable flow was only possible when the trap was multiply-connected, and was observed with a BEC fraction as small as 15%. We also created flow with two units of angular momentum, and observed its splitting into two singly-charged vortices when the trap geometry was changed from multiply- to simply-connected.Comment: 1 file, 5 figure