Chouaib Doukkali University

In this work, a new isatin derivative, namely 1-[2-(diethylamino)ethyl]-1H-indole-2,3-dione (5-HEI), was synthesized and its inhibitory effect on carbon steel in hydrochloric acid solution was estimated by gravimetric measurements, electrochemical impedance spectroscopy (EIS) and electrochemical potentiodynamic polarization. The steel surface was analyzed by SEM. The results obtained showed that this isatin derivative acts as an effective corrosion inhibitor for carbon steel in 1 M HCl, with an inhibition efficiency of 93.9% achieved with 1 mM after 6 hours of immersion at 303 K. Polarization curves suggested that 5-HEI acted as a mixed inhibitor. Charge transfer resistance values increased with increasing inhibitor concentration, as demonstrated by electrochemical impedance spectroscopy. The adsorption of 5-HEI onto the steel surface obeyed El-Awady's kinetic/thermodynamic model. Thermodynamic studies have indicated that the main mechanism controlling corrosion inhibition by 5-HEI involves a chemisorption process.

The development of numerical simulation software enables the modeling of complex physical phenomena that are difficult to detect in printed parts within the fused deposition modeling (FDM). However, simulating all possible combinations of process parameters, across factors and levels, remains time-consuming and computationally expensive. The use of numerical design of experiments (NDoE) is a relevant approach, as it enables the optimization and establishment of correlations between printing parameters and the associated physical phenomena. In this study, the influence of different printing temperatures (melting temperature, build-plate temperature, and ambient temperature) on polymer diffusion kinetics, filament coalescence (neck formation), and the resulting porosity is investigated numerically. The analysis is based on a two-dimensional numerical model that incorporates heat transfer and Schneider’s equations for crystallization simulation using multi-physics software. From these results, it is possible to evaluate filament coalescence, the degree of inter-filament healing, and interfacial porosity. Each parameter is analyzed separately to determine its individual influence on the phenomenon being investigated, and then the thermal interactions between these parameters are evaluated to better understand their combined effect on the physical mechanisms. The results indicate that higher build-plate temperatures, as well as prolonged exposure to processing ambient temperature, enhance inter-filament diffusion and reduce residual porosity. Moreover, changing the printing orientation from 0° to 90° leads to a significant increase in the degree of healing, rising from 0.55 to 0.71. In contrast, increasing the deposition temperature has only a limited effect on the initiation and development of these phenomena.

Mullite (Al6Si2O13), an aluminosilicate with remarkable thermal and dielectric properties, is a promising material for advanced electronic applications. This study focuses on a sintered mullite composite and examines its structural, morphological, dielectric, and electrical properties. X-ray diffraction and scanning electron microscopy analyses confirm a well-defined crystalline structure and a homogeneous microstructure. Impedance spectroscopy measurements reveal a high relative permittivity at low frequencies, dominated by interfacial and jump polarization mechanisms. Electrical conductivity follows Jonscher's double-power law, reflecting mixed ionic and electronic conduction due to contributions from grains and grain boundaries. Analysis of the Nyquist diagrams shows a marked decrease in resistances with increasing temperature: The grain resistance decreases from 21.87 M Omega to 4.85 M Omega, while that of the grain boundaries decreases from 89.44 M Omega to 5.94 M Omega between 450 degrees C and 900 degrees C. In addition, the relative permittivity increases sharply with temperature, from 25 & times; 103 to 350 & times; 103 at 1 kHz and from 200 to 1 & times; 103 at 1 MHz over the same temperature range, highlighting the dominant influence of temperature and low frequencies on polarization mechanisms. These results confirm the strong potential of sintered mullite for electronic applications. The activation energy of the grain and grain boundary were determined to be Ea,g = 0.18 eV and Ea,bg = 0.22 eV, respectively.

Drought is an increasing concern in Morocco’s semi-arid regions, where water resources are under growing pressure from climate variability and land degradation. Most previous studies on drought monitoring in Morocco have examined meteorological or hydrological dimensions separately, overlooking vegetation dynamics. This fragmented approach limits the ability to capture the full spectrum of drought impacts across natural and managed ecosystems. This study assesses drought dynamics in the Ahmed El Hansali Dam basin, located in the Upper Oum Er-Rbia watershed, during 1975–2023. The novelty of this research lies in the long-term, combined assessment of meteorological, hydrological, and remote sensing indices at the basin scale, providing one of the most comprehensive drought evaluations for Morocco’s inland watersheds. A multi-index approach combining Standardized Precipitation Index (SPI), Streamflow Drought Index (SDI), and Normalized Difference Vegetation Index (NDVI) was applied to assess meteorological, hydrological, and vegetation responses to drought. Meteorological data from five stations, hydrological inflows at the dam, and Landsat-derived NDVI composites were utilized. The SPI and SDI revealed a marked increase in drought frequency and severity beginning in the early 1990s, with the most critical period between 2020 and 2023. SPI values below − 1.5 and SDI near − 1.6 confirmed intensifying precipitation deficits and declining inflows. The NDVI showed moderate interannual variability with lower values during drought years, though weak correlation with SPI and SDI suggests that vegetation response is influenced by altitude, land cover, and soil water retention, and agricultural practices including irrigation. Spatial analyses highlighted the greater resilience of forested highlands compared to lower-elevation agricultural areas. Overall, the combined use of these three indices offers a robust picture of drought evolution in the basin. By bridging the gap between single-dimension studies and proposing a comprehensive multi-source monitoring framework, this work provides a more holistic understanding of drought impacts and delivers actionable insights for water resource managers and policymakers.

The transition zone between the Anti-Atlas Mountains and the Sub-Mesetian domain in Morocco is one of the most significant structural provinces at the northwestern side of the West African Craton, recording a long and complex geodynamic evolution that spans from the Pan-African orogeny to the Alpine deformations. In this framework, the present study aims to integrate high-resolution geophysical (Airborne Magnetic and Frequency Electromagnetic Methods) and field data to provide new insights into the tectonic evolution of this area. The results reveal new insights into the structural framework and tectonic evolution of the northern Saghro-Ougnat axis, underscoring its complex polyphase geodynamic history. The region’s evolution was governed by several major tectonic episodes associated with the Pan-African, Variscan, and Alpine orogenies. During the Precambrian, this area underwent a major NW-SE compressional phase that deformed the Lower Ediacaran Saghro Group, followed by successive extensional events, oriented NE-SW and later NW-SE, which controlled the emplacement and deposition of the Upper Ediacaran Ouarzazate Group. During the Cambrian, the tectonic regime shifted toward extension, producing a mosaic of north-tilted fault blocks linked to crustal thinning and differential subsidence. Subsequently, during the Variscan Orogeny, a renewed compressional regime reactivated and inverted pre-existing extensional structures. This deformation produced prominent E-W-oriented thrust zones south of the Tisdafine Basin, marking the trace of the South Meseta Fault, which is a major tectonic boundary separating the Anti-Atlas block from the Sub-Mesetian block. During the Meso-Cenozoic, the area experienced a renewed NNW-SSW extensional regime, which controlled the initiation and development of Atlasic rifting. This phase was later overprinted by compressional deformation associated with the Alpine Orogeny, resulting in crustal shortening, fault reactivation, and the structuring of the present-day Atlas system. The resulting structural map thus delineates the architecture and configuration of the northern Saghro-Ougnat axis, providing a clearer understanding of its role within the broader tectonic framework of the transition zone between the Anti-Atlas and Sub-Mesetian domains.