A laboratory program to develop improved grazing incidence X-ray optics

Grazing incident double reflection X-ray telescop

Presence metadata in the Internet of Things challenges and opportunities

The Internet of Things is an emerging computing paradigm that promises to revolutionise society. The widespread capture and aggregation of data from sensors and smart devices combined with processing using machine learning in cloud computing platforms provides unrivalled insights into our environment. In addition to the numerous benefits (smart healthcare, cities, transportation, etc.) such insights potentially jeopardise the privacy of individuals, organisations, and society as whole. This is despite UK and EU regulations attempting to mitigate the risk of individuals’ data exposure and the impact of it on their security. To demonstrate the exploitation of metadata and its threat to privacy, this paper presents Meta-Blue, a Bluetooth Low Energy metadata capture, analysis, and visualisation tool. The results of a case study are combined with an overview of literature on IoT privacy to provide a holistic overview of the challenges and opportunities presented by IoT metadata

Recurrence Spectroscopy in Time-Dependent Fields

Closed-orbit theory is a semiclassical technique for explaining the spectra of Rydberg atoms in external fields. We derive an alternative version of closed-orbit theory that applies when the external fields are time dependent. We compare the results of this theory with experiments on lithium atoms in a weak oscillating electric field

Evolution of suprathermal seed particle and solar energetic particle abundances

We report on a survey of the composition of solar-wind suprathermal tails and solar energetic particles (SEPs) including data from 1998 to 2010, with a focus on 2007 to 2010. The start of solar cycle 24 included several SEP events that were unusually He-poor. We conclude that these He-poor events are more likely related to Q/M-dependent spectral variations than to seed-particle composition changes. We also find that the quiet-time suprathermal Fe/O ratio during the 2008-2009 solar-minimum was dramatically lower (Fe/O ≤ 0.01) than earlier due in part to very low solar activity, but also suggesting contributions from an oxygen-rich source of suprathermal ions of unknown origin

Float zone processing in a weightless environment

Results are given for investigations into: (1) the physical limits which set the maximum practical diameters of Si crystals that can be processed by the float-zone method in a near weightless environment, and (2) the economic impact of large, space-produced Si crystals on the electronics industry. The stability of the melt is evaluated. Heat transfer and fluid flow within the melt as dependent on the crystal size and the degree and type of rotation imparted to the melt are studied. Methods of utilizing the weightless environment for the production of large, stress-free Si crystals of uniform composition are proposed. The economic effect of large size Si crystals, their potential applications, likely utilization and cost advantages in LSI, integrated circuits, and power devices are also evaluated. Foreseeable advantages of larger diameter wafers of good characteristics and the possibilities seen for greater perfection resulting from stress-free growth are discussed

Continuing data analysis of the AS/E grazing incidence X-ray telescope experiment on the OSO-4 satellite

The work to correct and extend the calculation of the theoretical solar X-ray spectrum produced during earlier OSO-4 data analysis is reported along with the work to formulate models of active regions, and compare these models with the experimental values. An atlas of solar X-ray photographs is included, and solar X-ray observations are correlated with the solar wind

Heavy Crane Foundations on Soft Clay

A very large mobile crane was used to lift a 3,150 kN steam generator through the roof of the containment building of a nuclear power plant. The maximum load on the crane was 19.8 MN, giving a track pressure of almost 600 kPa. Soil conditions were stiff clay underlain by softer clay. This paper describes the bearing capacity and settlement analysis performed to establish a suitable shallow foundation for the crane. The foundation load test confirmed that soil conditions had been adequately defined and that the foundation design was satisfactory

Extracting Classical Trajectories from Atomic Spectra

We describe how to reconstruct individual classical trajectories from spectroscopic data. The ac dipole moment of a trajectory can be found from the effect of an oscillating field on the spectrum. The inverse Fourier transform of such data yields the component of the electron trajectory along the direction of the oscillating field. We demonstrate the method by experimentally extracting z(t) for two electron trajectories that influence the Stark spectrum of Rydberg lithium. Within the experimental resolution, the reconstructed orbits agree well with classical predictions