Stability Analysis of the Mg2Si Phase in AA 6061 Aluminum Alloy

AbstractThe spent MTR fuel elements, manufactured with the aluminum-based alloy AA 6061, are stored under water in interim storage basins. In such conditions the AA 6061 is susceptible to degradation by localized corrosion processes which might be related to the behavior of second-phase particles present in the alloy.According to its electrochemical behavior, the second-phase particles present in AA 6061 can be classified into cathodic or anodic in relation to the aluminum matrix.In order to investigate the stability of the Mg2Si phase, which dissolves in high purity water, immersion and polarization tests were carried out in alkaline solutions. SEM and EDS were used to analyze the second-phase particles after the tests.It was determined that Mg2Si phase particles are stable in solutions of pH 8 to 14, and undergo selective magnesium dissolution from pH 7 to lower values

Hardy spaces for a class of singular domains

We set a framework for the study of Hardy spaces inherited by complements of analytic hypersurfaces in domains with a prior Hardy space structure. The inherited structure is a filtration, various aspects of which are studied in specific settings. For punctured planar domains, we prove a generalization of a famous rigidity lemma of Kerzman and Stein. A stabilization phenomenon is observed for egg domains. Finally, using proper holomorphic maps, we derive a filtration of Hardy spaces for certain power-generalized Hartogs triangles, although these domains fall outside the scope of the original framework

Amplified spontaneous emission and efficient tunable laser emission from a substituted thiophene-based oligomer

We investigated gain and lasing in spin-coated films of a soluble substituted oligothiophene. With increasing excitation power, the photoluminescence spectra show a clear line narrowing due to amplified spontaneous emission. We measure a low threshold (20 μJ cm−2) for line narrowing and a large gain cross section (6×10−16 cm2), indicating that this molecule is a promising active material for organic solid-state lasers. As a demonstrator, we realize a transverse electromagnetic (TEM00) single-mode laser with tunable emission from the yellow to the red (a range of 37 nm), with a pump threshold as low as 18 μJ cm−2 and efficiency of 1.9%. These results are among the best so far reported for organic lasers

Direct extraction of oil from sunflower seeds by twin-screw extruder according to an aqueous extraction process: Feasibility study and influence of operating conditions

The objective of this study was to evaluate the feasibility of an aqueous process to extract sunflower seed oil using a co-rotating twin-screw extruder. Aqueous extraction was carried out using whole seeds and the influence of the operating conditions on oil yield was examined. Operating conditions included screw profile, screw rotation speed, and input flow rates of sunflower seeds and water. Liquid/solid separation required the addition of a lignocellulosic residue upstream from the filtration zone. However, even with maximum fiber input flow, drying of the cake meal did not improve. The lixiviation of the sunflower seeds was also incomplete. The aqueous extraction of the oil was more efficient in the twin-screw extruder than the reference trial conducted in a batch reactor. The best oil extraction yield obtained was approximately 55% and the residual oil content of the cake meal was approximately 30%. The hydrophobic phases produced were oil-in-water emulsions. These emulsions were stabilized by phospholipids and proteins at the interface, which are natural surface-active agents co-extracted during the process

Electro-responsivity in electrolyte-free and solution processed Bragg stacks

Achieving an active manipulation of colours has huge implications in optoelectronics, as colour engineering can be exploited in a number of applications, ranging from display to lightning. In the last decade, the synergy of the highly pure colours of 1D photonic crystals, also known as Bragg stacks, with electro-tunable materials have been proposed as an interesting route to attain such a technologically relevant effect. However, recent works rely on the use of liquid electrolytes, which can pose issues in terms of chemical and environmental stability. Here, we report on the proof-of-concept of an electrolyte free and solution-processed electro-responsive Bragg stack. We integrate an electro-responsive plasmonic metal oxide, namely indium tin oxide, in a 1D photonic crystal structure made of alternating layers of ITO and TiO2 nanoparticles. In such a device, we observed a maximum of 23 nm blue-shift upon the application of an external bias (10 V). Our data suggest that electrochromism can be attained in all-solid state systems by combining a judicious selection of the constituent materials with device architecture optimisation. This journal i

Fully direct written organic micro-thermoelectric generators embedded in a plastic foil

Organic materials have attracted great interest for thermoelectric applications due to their tuneable electronic properties, solution processability and earth-abundance, potentially enabling high-throughput realization of low-cost devices for low-power energy harvesting applications. So far, organic thermoelectricity has primarily focused on materials development, with less attention given to integrated generators. Yet, future applications will require the combination of efficient generators architectures and scalable manufacturing techniques to leverage the advantages of such promising materials. Here we report the realization of a monolithic organic micro-thermoelectric generator (μ-OTEG), using only direct writing methods, embedding the thermoelectric legs within a plastic substrate through a combination of direct laser writing and inkjet printing techniques. Employing PEDOT:PSS for the p-type legs and a doped fullerene derivative for the n-type ones, we demonstrate a μ-OTEG with power density of 30.5 nW/cm2 under small thermal gradients, proving the concrete possibility of achieving power requirements of low-power, distributed sensing applications

Correction: Near-infrared emitting single squaraine dye aggregates with large Stokes shifts

Correction for 'Near-infrared emitting single squaraine dye aggregates with large Stokes shifts' by G. M. Paternò et al., J. Mater. Chem. C, 2017, 5, 7732–7738

Subpicosecond photoinduced Stark spectroscopy in fullerene-based devices

Published versio

Roadmap on semiconductor-cell biointerfaces.

This roadmap outlines the role semiconductor-based materials play in understanding the complex biophysical dynamics at multiple length scales, as well as the design and implementation of next-generation electronic, optoelectronic, and mechanical devices for biointerfaces. The roadmap emphasizes the advantages of semiconductor building blocks in interfacing, monitoring, and manipulating the activity of biological components, and discusses the possibility of using active semiconductor-cell interfaces for discovering new signaling processes in the biological world