534 research outputs found

    Gamification techniques for raising cyber security awareness

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    Due to the prevalence of online services in modern society, such as internet banking and social media, it is important for users to have an understanding of basic security measures in order to keep themselves safe online. However, users often do not know how to make their online interactions secure, which demonstrates an educational need in this area. Gamification has grown in popularity in recent years and has been used to teach people about a range of subjects. This paper presents an exploratory study investigating the use of gamification techniques to educate average users about password security, with the aim of raising overall security awareness. To explore the impact of such techniques, a role-playing quiz application (RPG) was developed for the Android platform to educate users about password security. Results gained from the work highlightedthat users enjoyed learning via the use of the password application, and felt they benefitted from the inclusion of gamification techniques. Future work seeks to expand the prototype into a full solution, covering a range of security awareness issues

    Ionic and electronic properties of the topological insulator Bi2_2Te2_2Se investigated using β\beta-detected nuclear magnetic relaxation and resonance of 8^8Li

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    We report measurements on the high temperature ionic and low temperature electronic properties of the 3D topological insulator Bi2_2Te2_2Se using ion-implanted 8^8Li β\beta-detected nuclear magnetic relaxation and resonance. With implantation energies in the range 5-28 keV, the probes penetrate beyond the expected range of the topological surface state, but are still within 250 nm of the surface. At temperatures above ~150 K, spin-lattice relaxation measurements reveal isolated 8^8Li+^{+} diffusion with an activation energy EA=0.185(8)E_{A} = 0.185(8) eV and attempt frequency τ01=8(3)×1011\tau_{0}^{-1} = 8(3) \times 10^{11} s1^{-1} for atomic site-to-site hopping. At lower temperature, we find a linear Korringa-like relaxation mechanism with a field dependent slope and intercept, which is accompanied by an anomalous field dependence to the resonance shift. We suggest that these may be related to a strong contribution from orbital currents or the magnetic freezeout of charge carriers in this heavily compensated semiconductor, but that conventional theories are unable to account for the extent of the field dependence. Conventional NMR of the stable host nuclei may help elucidate their origin.Comment: 17 pages, 12 figures, submitted to Phys. Rev.

    Future perspectives for alkali-activated materials: from existing standards to structural applications

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    The production of cement and concrete contributes significantly to global greenhouse gas emissions. Alkali-activated concretes (AACs) are a family of existing alternative construction materials that could reduce the current environmental impact of Portland cement (PC) production and utilisation. Successful applications of AACs can be found in Europe and the former USSR since the 1950s and more recently in Australia, China and North America, proving their potential as construction materials. However, their utilisation is limited presently by the lack of normative and construction guidelines. Raw materials’ non-uniform global availability and variable intrinsic properties, coupled with the lack of specific testing methods, raise questions regarding reproducibility and reliability. The mechanical and chemical behaviour of AACs has been investigated extensively over the past decades, strengthening its potential as a sustainable substitute for traditional PC-based concrete. Although a wide amount of studies demonstrated that AACs could meet and even exceed the performance requirements provided by European design standards, a classification of these broad spectra of materials, as well as new analytical models linking the chemistry of the system components to the mechanical behaviour of the material, still need further development. This report gives an overview of the potential of alkali-activated systems technology, focusing on the limitations and challenges still hindering their standardisation and wider application in the construction field

    Energy transfer in pendant perylene diimide copolymers

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    We report the synthesis, characterisation and polymerisation of two novel asymmetric perylene diimide acrylate monomers. The novel monomers form a sensitiser–acceptor pair capable of undergoing Förster resonance energy transfer, and were incorporated as copolymers with tert-butyl acrylate. The tert-butyl acrylate units act as spacers along the polymer chain allowing high concentrations of dye while mitigating aggregate quenching, leading to persistent fluorescence in the solid state at high concentrations of up to 0.3 M. Analysis of fluorescence kinetics showed efficient energy transfer between the optically dense sensitiser and the lower concentration acceptor luminophores within the polymer. This reduced reabsorption within the material demonstrates that the copolymer-scaffold energy transfer system has potential for use in luminescent solar concentrators

    Beam-Normal Single Spin Asymmetry in Elastic Electron Scattering off 28^{28}Si and 90^{90}Zr

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    We report on a new measurement of the beam-normal single spin asymmetry AnA_{\mathrm{n}} in the elastic scattering of 570 MeV transversely polarized electrons off 28^{28}Si and 90^{90}Zr at Q2=0.04GeV2/c2Q^{2}=0.04\, \mathrm{GeV}^2/c^2. The studied kinematics allow for a comprehensive comparison with former results on 12^{12}C. No significant mass dependence of the beam-normal single spin asymmetry is observed in the mass regime from 12^{12}C to 90^{90}Zr.Comment: Submitted for publication to Physics Letters

    Depth-resolved measurement of the Meissner screening profile in a niobium thin film from spin-lattice relaxation of the implanted β\beta-emitter 8^{8}Li

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    We report measurements of the Meissner screening profile in a Nb(300 nm)/Al2_{2}O3_{3} thin film using 8^{8}Li β\beta-detected nuclear magnetic resonance (β\beta-NMR). The NMR probe 8^{8}Li was ion-implanted into the Nb film at energies \leq 20 keV, corresponding to mean stopping depths comparable to Nb's magnetic penetration depth λ\lambda. 8^{8}Li's strong dipole-dipole coupling with the host 93^{93}Nb nuclei provided a "cross-relaxation" channel that dominated in low magnetic fields, which conferred indirect sensitivity to the local magnetic field via the spin-lattice relaxation (SLR) rate 1/T11/T_{1}. From a fit of the 1/T11/T_{1} data to a model accounting for its dependence on temperature, magnetic field, and 8^{8}Li+^{+} implantation energy, we obtained a magnetic penetration depth λ0\lambda_{0} = 51.5(22) nm, consistent with a relatively short carrier mean-free-path \ell = 18.7(29) nm typical of similarly prepared Nb films. The results presented here constitute an important step towards using 8^{8}Li β\beta-NMR to characterize bulk Nb samples with engineered surfaces, which are often used in the fabrication of particle accelerators.Comment: 16 pages, 4 figure
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