Sustainability and multifunctionality for next-generation construction materials

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Numerical Simulation of Turbulent Flow Through a Straight Square Duct

Turbulent duct flows are investigated using large eddy simulation at bulk Reynolds numbers, from 4410 to 250,000. Mean secondary flow is found to reveal the existence of two streamwise counter-rotating vortices in each corner of the duct. Turbulence-driven secondary motions that arise in duct flows act to transfer fluid momentum from the centre of the duct to its corners, thereby causing a bulging of the streamwise velocity contours towards the corners. As Reynolds number increases, the ratio of centreline streamwise velocity to the bulk velocity decreases and all turbulent components increase. In addition, the core of the secondary vortex in the lower corner-bisector tends to approach the wall and the corner with increasing Reynolds number. The turbulence intensity profiles for the low Reynolds number flows are quite different from those for the high Reynolds number flows. Typical turbulence structures in duct flows are found to be responsible for the interactions between ejections from wall and this interaction results in the bending of the ejection stems, which indicates that the existence of streaky wall structures is much like in a channel flow

"Women's rights, the European Court and Supranational Constitutionalism"

This analysis examines supranational constitutionalism in the European Union. In particular, the study focuses on the role of the European Court of Justice in the creation of women’s rights. I examine the interaction between the Court and member state governments in legal integration, and also the integral role that women’s advocates – both individual activists and groups – have played in the development of EU social provisions. The findings suggest that this litigation dynamic can have the effect of fueling the integration process by creating new rights that may empower social actors and EU organizations, with the ultimate effect of diminishing member state government control over the scope and direction of EU law. This study focuses specifically on gender equality law, yet provides a general framework for examining the case law in subsequent legal domains, with the purpose of providing a more nuanced understanding of supranational governance and constitutionalism

Heliophysics and Amateur Radio:Citizen Science Collaborations for Atmospheric, Ionospheric, and Space Physics Research and Operations

The amateur radio community is a global, highly engaged, and technical community with an intense interest in space weather, its underlying physics, and how it impacts radio communications. The large-scale observational capabilities of distributed instrumentation fielded by amateur radio operators and radio science enthusiasts offers a tremendous opportunity to advance the fields of heliophysics, radio science, and space weather. Well-established amateur radio networks like the RBN, WSPRNet, and PSKReporter already provide rich, ever-growing, long-term data of bottomside ionospheric observations. Up-and-coming purpose-built citizen science networks, and their associated novel instruments, offer opportunities for citizen scientists, professional researchers, and industry to field networks for specific science questions and operational needs. Here, we discuss the scientific and technical capabilities of the global amateur radio community, review methods of collaboration between the amateur radio and professional scientific community, and review recent peer-reviewed studies that have made use of amateur radio data and methods. Finally, we present recommendations submitted to the U.S. National Academy of Science Decadal Survey for Solar and Space Physics (Heliophysics) 2024–2033 for using amateur radio to further advance heliophysics and for fostering deeper collaborations between the professional science and amateur radio communities. Technical recommendations include increasing support for distributed instrumentation fielded by amateur radio operators and citizen scientists, developing novel transmissions of RF signals that can be used in citizen science experiments, developing new amateur radio modes that simultaneously allow for communications and ionospheric sounding, and formally incorporating the amateur radio community and its observational assets into the Space Weather R2O2R framework. Collaborative recommendations include allocating resources for amateur radio citizen science research projects and activities, developing amateur radio research and educational activities in collaboration with leading organizations within the amateur radio community, facilitating communication and collegiality between professional researchers and amateurs, ensuring that proposed projects are of a mutual benefit to both the professional research and amateur radio communities, and working towards diverse, equitable, and inclusive communities

Combined Experimental and Computational Prediction of the Piezoresistivity of Alkali-Activated Inorganic Polymers

The incorporation of smart building materials into construction will improve the working life of structures and infrastructure around the globe. Unfortunately, conventional smart building materials are cost-prohibitive because of the self-sensing additives required. Alkali-activated inorganic polymers are a promising low-cost and environmentally friendly alternative that exhibit intrinsic self-sensing properties, without the need for self-sensing additives. An improved methodology has been developed to quantify the self-sensing piezoresistivity of these materials. Experimental measurements reveal a strong intrinsic piezoresistivity up to 12%. The results agree with a first-principles model of the theoretical piezoresistivity of an alkali-activated inorganic polymer from the quantum mechanical perturbation theory. This first-of-its-kind computation provides a mechanistic explanation for the origin of intrinsic piezoresistivity in inorganic polymers

Experimental Investigation of a RQL Burner with Jet in Cross Flow Fuel Injection - Characterization of the Reating Flow Field at Realistic Operating Conditions

Future rich-burn/quick-quench/lean-burn (RQL) burners for aero engines face the challenge to further reduce the emission of soot. Alternative ways of fuel injection are therefore in the focus of modern RQL combustion systems. This contribution aims to investigate experimentally the influence of fuel injection on the reacting flow field, with the emphasis on soot production in the primary zone. For the test, a Rolls-Royce prototype burner was used in two different configurations which differ only in the axial location of jet in cross flow fuel injection and thereby provoke different ways of fuel atomization. In the upstream configuration the burner features characteristics of a pre-filming airblast atomizer. Whereas with the fuel tip in downstream position solely Jet-in-Cross-Flow fuel atomisation is expected. The burner was tested at realistic aero engine combustor conditions (p30=9.28 bar, T30=603 K, AFR=7.6). Several optical measurement techniques were used to characterise the reacting flow field. Their difficult application in a rich burn environment is described briefly. The structure of the reacting flow field is illustrated by ParticleImage-Velocimetry (PIV). Planar Mie scattering and Planar Laser-Induced Fluorescence (PLIF) are used to characterise the placement of liquid and gaseous fuel respectively. The location and structure of heat release zones are captured in terms of OH* and CO2* chemiluminescence. Finally LaserInduced-Incandescence (LII) is used to obtain three dimensional soot distributions in the primary zone. On this basis 20% less soot was measured for the upstream configuration at the axial location of maximal soot concentration. This remarkable difference could be attributed to the different placement of liquid fuel and the resulting better mixing

Suppression of ionospheric irregularity due to auroral particle impact

The VISIONS-2 35.039 sounding rocket was launched from Ny-Ålesund, Svalbard, on 7 December 2018 at 11:06 UT, and traveled overhead of the cusp aurora. The payload reached an apogee of 806.6 km and provided measurements of the electric field (E) and electron density (Ne ) with a high sampling rate of 6,250 Hz. The high-sampling-data make it possible to estimate the horizontal structure of E and Ne on scales ranging from meters to kilometers scale. The horizontal variation in the electron density and electric field (ΔNe /Ne and ΔE) and integrated power of Ne and E (ΣPNe and ΣPE) for 1–10, 10–100, and 100–1,000 Hz range were derived. The derived values were compared with the 557.7 and 630.0 nm emission intensities obtained from an all-sky camera installed in Ny-Ålesund projected at the footprint of the rocket, which was calculated by tracing the Earth's magnetic field line from the rocket altitude to the emission layer. ΔNe /Ne , ΔE, ΣPNe, and ΣPE increased with the 630.0 nm emission intensity. Of particular interest is the lower level irregularity was observed when the 557.7 nm emission intensity exceeded 4.5 kR compared with other time interval. This may suggest that particle impact ionization created sufficient Pedersen conductance in the E-region to short the F-region current. This short-circuit seemed to cause the suppression of the irregularities in the F-region and lower level irregularities were also observed in the rocket altitude