Research Institute for Autonomous Precision Guided Systems

Abstract

The 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 this collection of information, including suggestions for reducing the burden, to Department of Defense. Washington Headquarters Services. Directorate for Information Under the leadership of Dr. Rogacki and Dr. Albertani there was significant progress made in delivering a hardware-in-the-loop rapid prototyping capability at the UF-REEF. Embedded systems are designed to control complex plants such as land vehicles, satellites, spacecrafts, unmanned aerial vehicles (UAVs), aircrafts, weapon systems, marine vehicles, and jet engines. They generally require a high level of complexity within the embedded system to manage the complexity of the plant under control. Hardware-in-the-Loop (HIL) simulation is a technique that is used increasingly in the development and test of complex real-time embedded systems.The purpose of HIL simulation is to provide an effective platform for developing and testing real-time embedded systems. HIL simulation provides an effective platform by adding the complexity of the plant under control to the test platform. The complexity of the plant under control is included in test and development by adding a mathematical representation of all related dynamic systems. These mathematical representations are referred to as the "plant simulation.'" The UF-REEF has established a HIL simulation capability for MAV's that will lead to a rapid prototyping capability.The Task 1 research plan included testing the visual based control system running on the cluster PCs in the REEF Visualization Lab by flying a relatively stable off the shelf slow flier (similar to MAV flight regime) in the small REEF wind tunnel and later in the large wind tunnel. The general layout of the test bed is illustrated in Fig. 2.

Effect of Magnetic Impurities in a Two-Band Superconductor: A Point-Contact Study of Mn-SubstitutedMgB2Single Crystals

“…The bulk critical temperature T c was determined by DC magnetization measurements. As reported elsewhere [5], the dependence of the lattice constants on the Mn content indicates that Mn replaces Mg in the lattice. The magnetic-field dependence of the Curie part C * of the magnetic moment M clearly indicates that Mn ions are divalent (i.e.…”

“…The complete dependence of the OPs on T A c is reported in Fig. 4 BTK fit are shown, based on the preceding discussion and on the regular trend of the OPs for T A c ≥ 18 K. In fact, the presence of a single OP in the low-T A c region would imply a sudden change in the slope of the curves around T A c = 17 K that is not justified by any observed discontinuity in the physical properties of the compound [5]. The persistence of two distinct OPs up to the highest x value indicates that Mn doping does not significantly increase non-spin-flip interband scattering.…”

“…Actually, this is also suggested by the very low Mn concentration (1.5 % at most) and by the decrease of both the OPs with T A c (while interband scattering would increase ∆ π [15]). This decrease could arise from changes in the DOSs at the Fermi level [15] and in the phonon spectra α 2 F σ,π (ω), but these two effects are certainly negligible here, because Mn is isovalent with Mg [5] and the Mn content is very small. The latter reason also allows assuming the effect of σ and π intraband non-spin-flip scattering to be much smaller than that of pair-breaking scattering in the same channels.…”

“…Substitutions with magnetic impurities (Mn, Fe) represent a class of its own because of the spin-flip pair-breaking scattering that is expected to dramatically suppress superconductivityeven though the way it does it in a two-band superconductor has never been studied experimentally. Up to now, only two successful Mn substitution in the Mg site have been reported, one in polycrystalline samples [4] and one in single crystals [5]. Here, we present the first results of point-contact spectroscopy (PCS) measurements in Mn-substituted MgB 2 single crystals grown at ETHZ, which allowed us to study the effects of magnetic impurities on the order parameters (OPs) of a two-band superconductor.…”

“…The high-quality Mg 1−x Mn x B 2 single crystals used for our measurements were grown by using the same highpressure, cubic-anvil technique set up for pure MgB 2 , and by replacing part of the Mg precursor with metallic Mn [5]. The Mn content x of each crystal was measured by EDX through a careful evaluation of the Mn/Mg ratio; the crystals are single-phase and homogeneous within ±δx (δx=0.0010).…”