Operational application of a universal turbulence measuring system Final report

Aeronautical turbulence measuring apparatus - gust loadin

Low Precision Table Based Complex Reciprocal Approximation

International audienceA recently proposed complex valued division algorithm designed for efficient hardware implementations requires a prescaling step by a constant factor. Techniques for obtaining this prescaling factor have been mentioned by the authors, which serves to justify the feasibility of the algorithm but is inadequate for obtaining efficient implementations. Table based solutions are formulated in this paper for obtaining the prescaling factor, a low precision reciprocal approximation for a complex value, using techniques adopted from univariate function approximations. Two separate designs are proposed, one using a single table (a reference design) and another using generalized multipartite tables. The main contribution of this work is the extension of generalized multipartite table methods to a function of two variables. The multipartite tables derived were up to 67% more memory efficient than their single table counterparts

Automated data collection system applied to Hall effect and resistivity measurements

Automated Hall effect and resistivity apparatus for studying electrical transport properties of semiconductor

Radiation effects on silicon solar cells Final report, Dec. 1, 1961 - Dec. 31, 1962

Displacement defects in silicon solar cells by high energy electron irradiation using electron spin resonance, galvanometric, excess carrier lifetime, and infrared absorption measurement

Surface temperature mapping with infrared photographic pyrometry for turbine cooling investigations

Surface temperature mapping with infrared photographic pyrometry for turbine cooling investigation

Development of improved thermoelectric mater- ials for spacecraft applications final summary report, 29 jun. 1964 - 29 jun. 1965

Thermoelectric materials for spacecraft applications - optimization of bismuth-antimony alloys and ag-sb-fe-te-se system alloys for thermoelectric cooling in space environmen

The chemical and magnetic structural characterisation of magneto-resistive devices using x-ray techniques

The academic and industrial interest in magnetic data storage has been fuelled by the information age. The number of applications for magnetic thin-films has increased rapidly, along with the popularity of using X-ray techniques as a tool by which to characterise them. Structural characterisation is a key process to their development and understanding, correlating chemical and magnetic structure to magneto-transport. In this thesis a number of magneto-resistive devices are studied, including spin-valves, magnetic tunnel junctions and magnetic multilayers. The credence of using grazing incidence X-ray techniques for characterisation is initially demonstrated by accounting for variations in MR from nominally identical spin-valves, through observing subtle fluctuations in the pinning NiO layer thickness. The study of magnetic tunnel junctions has revealed discrepancies in barrier thickness as measured by X-ray reflectivity and through fits to the 1-V profile using Simmons’ model. This demonstrates localised tunnelling and the inaccuracy of 1-V modelling in determining average barrier thickness. Specular reflectivity and diffuse analysis have also determined a far larger than expected level of intermixing across Al bilayer interfaces with Al on X and X on Al, where X are transition metals from groups 3,4 and 5 of the periodic table. AF coupled multilayers are studied using polarised neutron reflectivity, the results of which have been compared directly with the relatively new technique: resonant soft X- ray magnetic scattering (SoXMaS). Specular and diffuse scattering studies reveal striking discrepancies between the two techniques, due to differences between the relative magnetic to chemical cross sections. Simulations further demonstrate SoXMaS and its sensitivity to magnetic structure. Finally, reflectivity data from Co/Cu Bragg peaks are used to calculate the refractive index of Co across the Co Lm and Ln edge under different magnetisation orientations