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The use of iron waste in concrete is now of considerable importance, mainly because of the benefits for the environment and for improving the strength of concrete. The increased and unused of this industrial byproducts represents a challenge for the environment and human health. This article experimentally explores the influence of utilizing iron powder waste and iron fibers in concrete in order to enhance the thermophysical properties of concrete and reduce the environmental impact resulting from iron waste. The aim of this work is to study the thermophysical properties (thermal conductivity, volumetric heat capacity, thermal diffusivity and thermal effusivity) of concrete with waste iron powder and iron fibers for application in building construction. The iron powder waste was added to the concrete with different percentages of 0%, 5%, 15%, 20% and 25% respectively as a partial replacement of sand. The iron fibers were added with mix proportions including 1.0%, 1.5%, 2.0% and 2.5% by volume of concrete, and in two different arrangements, uniform and random. The thermal conductivity and the volumetric heat capacity of these samples were measured experimentally in the dry state at ambient temperature (20 °C), and at 28 days of age. The effect of the integration of iron powder and fiber on thermal properties was analysed.

This critical review delves into the impact of Computational Fluid Dynamics (CFD) modeling techniques, specifically 2D, 2.5D, and 3D simulations, on the performance and vortex dynamics of Darrieus turbines. The central aim is to dissect the disparities apparent in numerical outcomes derived from these simulation methodologies when assessing the power coefficient ( C p ) within a defined velocity ratio (λ) range. The examination delves into the prevalent turbulence models shaping C p values, and offers insightful visual aids to expound upon their influence. Furthermore, the review underscores the predominant rationale behind the adoption of 2D CFD modeling, attributed to its computationally efficient nature vis-à-vis the more intricate 2.5D or 3D approaches, particularly when gauging the turbine's performance within the designated λ realm. Moreover, the study meticulously curates a compendium of findings from an expansive collection of over 250 published articles. These findings encapsulate the evolution of pivotal parameters, including C p , moment coefficient ( C m ), lift coefficient ( C l ), and drag coefficient ( C d ), as well as the intricate portrayal of velocity contours, pressure distributions, vorticity patterns, turbulent kinetic energy dynamics, streamlines, and Q-criterion analyses of vorticity. An additional focal point of the review revolves around the discernment of executing 2D parametric investigations to optimize Darrieus turbine efficacy. This practice persists despite the emergence of turbulent flow structures induced by geometric modifications. Notably, the limitations inherent to the 2D methodology are vividly exemplified through compelling CFD contour representations interspersed throughout the review. Vitally, the review underscores that gauging the accuracy and validation of CFD models based solely on the comparison of C p values against experimental data falls short. Instead, the validation of CFD models rests on time-averaged C p values, thereby underscoring the need to account for the intricate vortex patterns in the turbine's wake—a facet that diverges significantly between 2D and 3D simulations. In a bid to showcase the extant disparities in CFD modeling of Darrieus turbine behavior and facilitate the selection of the most judicious CFD modeling approach, the review diligently presents and appraises outcomes from diverse research endeavors published across esteemed scientific journals. [ABSTRACT FROM AUTHOR]

Acknowledgments Moreover, we would like to thank all the institutions and personnel involved in operating the Iberarray temporary seismic networks in Iberia and North Africa, and ORFEUS/EIDA for the available data. [Extracted from the article]

The following study aims at investigating the 2D distribution of the seismic wave attenuation based on the quality factor of the seismic coda waves in the northern part of Morocco. In this regard, the waveforms of 66 local earthquakes have been analyzed. The waveforms were recorded from 26 broadband seismic stations deployed by the Scientific Institute of Rabat during 2008, through the different structural domains. The coda wave seismic quality factor (QC) has been extracted through the application of the back-scattering model proposed by Aki and Chouet (1975) using four central frequencies (1.5, 3, 6, and 12 Hz) and through four lapse time windows (30, 40, 50, and 60 s). Additionally, spatial distribution maps of the quality factor of the coda waves, for this region, were generated. The study area, based on the 2D maps of the quality factor, has revealed the existence of several stable anomalies of the QC values for all frequencies and for all windows used, Al-Hoceima and Nador regions for instance, and has shown that all territory under study can be divided into five different zones. The comparison of the spatial variations of the seismic wave attenuation, geological, and geophysical characteristics of the Northern Morocco shows that the seismic attenuation correlates with the seismic activity, the position of the fault zones, the heat flow, and the Cenozoic volcanism. Furthermore, the attenuation of the coda waves decreases with the lapse time window increasing (and accordingly with the depth of the seismic wave penetrating). Such behavior in the Q-factor may indicate that the upper part of the lithosphere is more heterogeneous compared to the lower layers. These results can be used not only for scientific research, but also in the practice domain for the calculation of the earthquake source parameters or in the mapping of seismic hazard. [ABSTRACT FROM AUTHOR]