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Intensification of Climate Extremes in the Sudanian Zone of Benin: Diagnosis Based on ETCCDI Indices Intensification des Extrêmes Climatiques Dans le Domaine Soudanien au Bénin: Diagnostic Basé Sur les Indices Etccdi

ynoptic stations over the period 1981-2025. Extreme rainfall and temperature events were determined using XLSTAT 2018 for the computation of 20 ETCCDI indices derived from Rclimdex 2.0, coupled with the Mann-Kendall trend test. A marked spatial variability in annual precipitation (PRCPTOT) was evidenced, with totals ranging from 750 to 2,000 mm yr-1; the highest accumulations were observed in the southern sector (Savalou, Glazoue, Ouesse), while the lowest values (746-913 mm) were recorded in the extreme north (Karimama and Malanville). Extreme indices further corroborate this intensification: RX5day reached 90-110 mm, R99p exceeded 115 mm, R95p ranged between 60 and 100 mm, while R1day surpassed 35 mm day-1 and the Simple Daily Intensity Index (SDII) exceeded 9 mm day-1 in the southeastern part. Analysis of temperature extremes at Parakou indicated significant increases in tropical nights (TR = 2.15; p = 0.03) and warm nights (TN90p = 4.13; p < 0.001), alongside rising extreme maximum values (TXX = 2.18; p = 0.03; TNX = 2.11; p = 0.03). Furthermore, cold spell duration indices (CSDI) exhibited a significant decline (Z = -3.75; p < 0.001). In contrast, at Kandi, the trends were more moderate, with an increase in warm nights (TN90p = 2.86; p = 0.004) and a significant decrease in extreme minima (TNN = -2.65; p = 0.008). These climatic and bioclimatic trends underscore the vulnerability of human health and point toward the need for sustainable, resilient adaptation strategies for local populations. Resume-L'analyse des indices climatiques ETCCDI au niveau des stations du domaine soudanien au Benin a montre l'intensification des extremes pluviometriques et thermometriques. Les donnees utilisees sont les releves de pluies et de temperatures (maximales et minimales) journalieres de 22 postes pluviometriques et de deux stations synoptiques sur la periode de 1981-2025. Les extremes de pluies et de temperature ont ete determines a l'aide du logiciel XLSTAT 2018 pour le calcul de 20 indices de l'ETCCDI a partir de Rclimdex 2.0 et du test de tendance de Mann-Kendall. Une forte variabilite spatiale des precipitations annuelles (PRCPTOT) est mise en evidence, avec des cumuls de 750 a 2 000 mm/an, les plus eleves observes au sud (Savalou, Glazoue, Ouesse) et de 746-913 mm, les plus faibles a l'extreme nord (Karimama et Malanville). Les indices extremes confirment cette intensification : RX5day atteint 90-110 mm, R99p depasse 115 mm, R95p varie entre 60 et 100 mm, tandis que R1day depasse 35 mm/jour et que le SDII atteint plus de 9 mm/jour au sud-est. L'analyse des extremes de temperature a montre qu'a Parakou, les indices revelent une hausse significative des nuits tropicales (TR = 2,15 ; p = 0,03) et des nuits chaudes (TN90p = 4,13 ; p < 0,001), accompagnee d'une augmentation des valeurs maximales extremes (TXX = 2,18 ; p = 0,03 ; TNX = 2,11 ; p = 0,03). En outre, les vagues de froid (CSDI) ont baisse significativement (Z = -3,75 ; p < 0,001). Par contre, a Kandi, l'evolution est plus moderee avec la hausse des nuits chaudes (TN90p = 2,86 ; p = 0,004) et la baisse significative des minima extremes (TNN = -2,65 ; p = 0,008). Cette tendance climatique et bioclimatique renseigne sur la vulnerabilite de la sante humaine et oriente vers les perspectives de strategies resilientes durables des populations.

Experimental Assessment of Compact Holographic Lens Imaging Systems for In-Plane Displacement Measurements

Arasad Ali Khan

Coherent imaging systems using holographic lenses have demonstrated significant potential in speckle metrology for diffraction-limited imaging performance free of all monochromatic aberrations. In this work, a compact four-hololens system has been investigated for in-plane displacement measurement and compared with two-hololens and double-aperture two-hololens imaging systems. Experimental results obtained using holographic lenses with a typical f-number 7.1 demonstrate that by employing an appropriate recording and reconstruction geometry for holographic lenses, the four-hololens configuration provides higher measurement sensitivity, reducing the minimum measurable in-plane displacement than the existing two-hololens systems.

Experimental Assessment of a Compact Four-Hololens Imaging System Using Holographic Lenses from Glass and Emulsion Sides for In-Plane Displacement Measurement

Arasad Ali Khan

To achieve diffraction-limited imaging over extended objects with negligible monochromatic aberrations, coherent imaging systems based on two identical holographic lenses in a conjugate arrangement have gained considerable attention in speckle metrology. However, the measurement sensitivity, defined as the minimum measurable in-plane displacement of a two-hololens system, is limited by the f-number of the holographic lenses. To overcome the dependency of measurement sensitivity on f-number of holographic lenses, the use of a double-aperture four-hololens system is investigated. Holographic lenses are employed from both emulsion and glass sides in the four-hololens system. Experiments were performed using holographic lenses recorded with a typical f-number of 7.1 and inter-beam recording angles of 11° and 18° between the plane and spherical recording beams. The experimental results demonstrate that holographic lenses recorded with a larger inter-beam recording angle provide high measurement sensitivity, while the use of holographic lenses from emulsion and glass sides has no significant effect on the in-plane displacement measurement. Furthermore, employing holographic lenses on both the emulsion and glass sides facilitates the easy alignment of the holographic lenses within the four-hololens system.

Natural Frequencies and Vibration Modes of an Aeronautical Axial Compressor Blade and Disk

Julia Dantas Gomes, Geraldo Creci

This article presents the natural frequencies and vibration modes of the blade and disk of the first stage of an axial compressor from a 5-kN thrust aeronautical gas turbine. The determination of the natural frequencies and vibration modes of these components enables an assessment of their dynamic behavior relative to the operating range, aiming to avoid resonance. There are no analytical solutions for the natural frequencies and vibration modes of structures with such complex geometries; therefore, calculations are performed using numerical computer simulations with Ansys® finite element software. To ensure the reliability of the results, the software is calibrated using simple beams for which analytical solutions exist. After verifying excellent agreement between the analytical solutions and the numerical computational results provided by Ansys® for simple beams, the same methodology is applied to the blade and disk of the first-stage axial compressor, which feature complex geometries. The results obtained for the blade and disk of the aeronautical axial compressor under study show excellent consistency - given the geometry and material used - and allow for an assessment of the components' dynamic behavior to prevent resonance-related issues.

Determination of Time Step and Grid Size Based on the Formulation Conditions of the Fundamental Hydrodynamic Equations for Time-Series Numerical Water Wave Modeling

Syawaluddin Hutahaean

The formulation of the fundamental hydrodynamic equations is based on two key assumptions. The first arises from the derivation of the Euler momentum conservation equation, which assumes that the temporal and spatial increments (dt, dx) are sufficiently small for the Taylor series expansion to be truncated after the first-order terms. The second assumption is associated with the continuity equation, in which the fluid-particle velocity is assumed to remain constant over the small time interval dt. Based on these two assumptions, two optimization equations are formulated with two unknowns, time step and grid size (dt, dx). Solving these equations provides the optimal time step and grid size for numerical simulations. The resulting values are consistent with the assumptions underlying the derivation of the fundamental hydrodynamic equations while also satisfying the requirement of sufficiently small discretization intervals imposed by numerical methods. The proposed approach enables more accurate numerical simulations of challenging wave conditions, particularly during wave breaking and post-breaking propagation.

A Meta-Synthesis of Murabahah Accounting Practices in Sharia-Compliant Entities Worldwide

This study aims to explore global Murabahah accounting practices and develop a structured conceptual understanding of how these practices are implemented within Sharia entities. This study adopts a meta-synthesis approach by systematically reviewing qualitative studies related to Murabahah accounting practices. Relevant literature was identified through searches in the Scopus and Google Scholar databases. The study followed six analytical stages of meta-synthesis. From an initial pool of 105 articles, 20 studies that met the research criteria were selected for in-depth analysis. The findings indicate varying levels of Sharia compliance, with some institutions demonstrating partial or inconsistent adherence to Murabahah accounting standards. These variations reflect structural and ethical challenges in the implementation of Murabahah accounting. Drawing on Al-Ghazali’s ethical framework, the study argues that Murabahah accounting practices should not only comply with technical accounting standards but must also incorporate Akhlaq (moral integrity) and ethical conduct consistent with Sharia principles. This research is limited to the analysis of existing qualitative studies in order to construct a conceptual framework of Murabahah accounting practices. Future research should employ qualitative field studies to explore the dimensions and indicators underlying Murabahah practices, followed by quantitative testing to evaluate the role of moral ethics (Akhlaq) and Sharia compliance in shaping Murabahah accounting practices. This study contributes to the Islamic accounting literature by highlighting the ethical dimension of Murabahah accounting. It introduces the integration of Akhlaq as a moral foundation to reduce deviations from Sharia principles in Murabahah contracts within Islamic financial institutions.