Publications by authors named "A G Kyriazis"

Besides major advantages for telecommunication applications, vertical-cavity surface-emitting lasers (VCSELs) have attracted interest for their potential for neuro-inspired computing, frequency comb generation, or high-frequency spin oscillations. In the meantime, strain applied to the laser structure has been shown to have a significant impact on the laser emission properties such as the polarization dynamics or birefringence. In this work, we further explore the influence of strain on VCSELs and how this effect could be used to fine-tune the laser wavelength.

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Article Synopsis
  • Observing the curing reaction of epoxy resins is crucial for ensuring quality in fibre composite production, with electrical impedance spectra being a key monitoring method.
  • Impedance spectra reveal physical changes during curing: early stages are dominated by ionic conductivity and electrode polarization, while dipole relaxation takes over later; evaluating across an entire frequency spectrum is more effective than focusing on a single frequency.
  • A proposed frequency-dependent model simplifies the interpretation of complex raw spectral data, achieving a relative error of only 2.3% with five parameters, while indicating the need for changing key indicators as the curing process progresses.
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The ability to measure the degree of cure of epoxy resins is an important prerequisite for making manufacturing processes for fibre-reinforced plastics controllable. Since a number of physical properties change during the curing reaction of epoxy resins, a wide variety of measurement methods exist. In this article, different methods for cure monitoring of epoxy resins are applied to a room-temperature curing epoxy resin and then directly compared.

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Unlabelled: This paper investigates the dynamic conditional linkages between the Eurostoxx50, and the Eurostoxx600 and its sub-indices with COVID-19 deaths, gold, and crude oil. The Dynamic Conditional Correlations (DCC) methodology is employed and the period examined spans from 22 January 2020 until 10 July 2020. Econometric outcomes reveal that the European stock indices are modestly-to-strongly linked with gold in a positive direction and this prevents them from abrupt falls during the pandemic.

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Monitoring process parameters in the manufacture of composite structures is key to ensuring product quality and safety. Ideally, this can be done by sensors that are embedded during production and can remain as devices to monitor structural health. Extremely thin foil-based sensors weaken the finished workpiece very little.

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