Physical Science International Journal

Technical and Commercial Losses in the West African Interconnected Electricity Network: Challenges and Prospects

Mohamed Lamine Kourouma — 2026-04-13

In the West African region, power system integration through the West Africa Power Pool (WAPP) is a strategic initiative aimed at enhancing energy security and facilitating cross-border electricity trade. Despite significant progress in regional interconnections, the efficiency and financial performance of electricity networks remain severely constrained by high levels of technical and commercial losses. Recent assessments indicate that average technical losses reach approximately 9.1%, while non-technical (commercial) losses account for nearly 21%, revealing persistent structural deficiencies in network operation and management. Technical losses are primarily driven by aging infrastructure, overloaded transmission and distribution lines, inadequate maintenance practices, and the limited deployment of advanced monitoring and control systems such as SCADA and smart grid technologies. Commercial losses, on the other hand, result from inaccurate metering and billing systems, illegal connections, electricity theft, and low revenue collection rates, often compounded by weak governance and insufficient regulatory enforcement.

Addressing these challenges requires a comprehensive and coordinated approach, including network modernization through digitalization and smart metering, capacity building for utility operators, harmonization of regulatory frameworks across WAPP member states, and increased consumer awareness regarding responsible electricity consumption. Implementing such measures would significantly reduce system losses, improve the financial sustainability of power utilities, enhance supply reliability, and strengthen subregional energy cooperation in West Africa.

Study of D+3He and T+3He Reactions by Using Double Folding Potential at Astrophysical Relevant Energies

Nur Mohammad — 2026-04-13

Aims: The microscopic double folding potential is more superior over the conventional square-well potential as it more realistic to represents the nuclear interactions and the introduction of an imaginary potential provides an effective and compact way to model absorption in nuclear well.

Study Design: The computations of nucleus-nucleus potential are implemented in the framework of double folding model function with DDM3Y-Reid and DDM3Y-Paris effective N-N interaction. Among different kind of the effective interaction, the so-called DDM3Y interaction was used in the double folding potential calculations.

Methodology: At astrophysical energy regime, the study of the nuclear fusion cross-sections is formidable on account of the massive vastness of the Coulomb barrier, yield in a minute worth of the fusion cross-section. All achievement in the results on S-function towards light particles can gives a clear insights about Big Bang nucleosynthesis. Presently, we have theoretically examined the E dependence of S-function and nuclear fusion σ(E) for fusion reaction of light nuclei for ³He(D,P)⁴He and ³He(T,N+P)⁴He nuclear system using complex potential with Coulomb repulsive potential.

Results: The calculation of the cross section and S-function cooked in the foundation of the SRTM potential function approach.

Conclusion: Theoretical computed results matched with the experimental results.

Effect of Geomagnetic Storms on Space Weather during the Ascending Phase of Solar Cycle 24

C. M. Tiwari — 2026-04-17

Space weather disturbances are significantly influenced by geomagnetic storms, which arise from intensified solar wind-magnetosphere coupling. This study examines the correlative dynamics of solar activity indicators (Sunspot Number, F10.7 index), interplanetary parameters (solar wind plasma speed, IMF scalar B), and planetary geomagnetic activity (Dst, Ap, auroral electrojet indices) during this extraordinary space weather regime. A statistical methodology based on correlation analysis and linear regression techniques is employed using multi-source observational datasets (e.g., OMNI database and geomagnetic indices) to quantify relationships among these parameters. The analysis reveals a profound disassociation between solar activity eruption rate and terrestrial storm intensity. Even though solar activity indicators, like sunspot numbers, showed strong increases in solar activity towards solar maximum, equatorial ring current activity (Dst index) was notable for its lack of strong excursions (Dst ≤ -100 nT). This is attributed to the extraordinary expansion of Coronal Mass Ejections (CMEs) in the low-pressure solar wind, leading to a dilution of internal magnetic flux. The study concludes that geomagnetic activity was dominated by the kinematic energy of moderate-speed solar wind streams, as opposed to solar magnetic flux emergence. The kinematic energy of solar wind streams was responsible for sustaining localized high-latitude auroral substorms throughout this extraordinary space weather regime. The equatorial magnetic field was found to be undisturbed.

Numerical Study of the Thermal Behavior of a Wall Built with Different Materials in a Hot and Dry Climate

Jean Marie Compaore — 2026-04-18

This article presents a numerical study of the thermal behavior of walls made from different materials in a hot and dry climate, constituting a first step of thesis work. The main objective is to analyze the temperature evolution inside walls built of hollow cement blocks and local materials (CEB, CLB, and adobe), in order to identify the least performing material in terms of thermal insulation, with a view to subsequently improving its properties. The governing equations were solved using the finite element method, implemented in the COMSOL Multiphysics software (version 5.3). The study was structured around two axes: the analysis of the temperature evolution at the internal and external surfaces of the walls, and the study of the influence of the position of a cement and plaster-based coating layer on the thermal behavior of the walls. The results obtained indicate that temperature peaks are significantly higher in hollow cement block walls (38.55°C) than in those built with local materials [35.07-35.23°C]. These observations show that hollow cement block presents low thermal performance in Sahelian zones, due to its high capacity to rapidly accumulate heat. In perspective, future work will aim to propose solutions to improve the thermal performance of this material.

Experimental Validation of a COMSOL Multiphysics Model of Hygrothermal Transfer in a Bioclimatic Building with a Domed Roof

Kabore Arouna — 2026-04-30

The building sector is one of the most energy-intensive and has the most impact on the environment, due to the use of cement for the manufacture of cinder blocks and concrete. Earth-based materials, thanks to their good thermal inertia, combined with a good choice of roof shape, such as domed roofs, are an alternative for reducing energy consumption and improving thermal comfort. To highlight the hygrothermal performance of earthen buildings with domed roofs, numerical modelling and simulation are used. Modeling is a tool that allows to predict physical phenomena in the building and the modeler must ensure the model's ability to predict them accurately before any simulation. The objective of this study is to experimentally validate a numerical model describing the hygrothermal transfers in an earthen building built with a hemispherical dome roof. The numerical model is implemented in the Comsol Multiphysics software. The meteorological data of the site, the air temperature, the relative humidity of the indoor environment and the temperatures of the interior and exterior surfaces of the building walls are measured. The data acquisition system consists of thermocouples, solarimeters and moisture meters, and this data is processed with Excel and Origin Pro software. Comparison of the simulated data and the measured data shows good agreement. The evaluation of the validation indicators shows that the NMBE values are between -5.63% and 0.3%, the CVRMSE between 0.75% and 7.42% and R2 between 76% and 96%. These values meet the limits recommended by ASHRAE Guideline 14 and show that the model can be used to reliably simulate internal and external thermal variations in the building while highlighting the effects of thermal inertia in the building walls. This research thus proposes a validated model that can be used in future parametric studies and for the optimization of the thermal performance of buildings.

Impact of Tortuosity on Species Transport in PEMFCs Gas Diffusion Layers

Enonsi Augustin Leode — 2026-04-30

Proton exchange membrane fuel cells (PEMFCs) are electrochemical systems that directly convert the chemical energy of hydrogen into electricity, offering high energy efficiency and low environmental impact. Within these systems, the gas diffusion layer (GDL) plays a critical role in ensuring efficient reactant transport and uniform current distribution.

This study examines the influence of GDL tortuosity on PEMFC performance. A numerical model, incorporating the Maxwell-Stefan transport laws for multi-species diffusion, the Butler-Volmer equation for electrochemical kinetics, and Darcy’s law for flow in porous media, was developed using COMSOL Multiphysics. The main originality of this work lies in the explicit analysis of anisotropic tortuosity, contrasted with the isotropic case, in order to evaluate its effects on species transport and current density distribution.

The results show that increasing tortuosity significantly limits reactant diffusion, leading to a reduction in cell performance of up to 20-80 % at low current densities. Polarization curve analysis indicates a decrease in cell efficiency as tortuosity increases. In addition, anisotropic tortuosity induces spatial heterogeneities in diffusion pathways, resulting in non-uniform current density distribution and further performance losses. These findings highlight the critical role of GDL microstructure in PEMFC operation and provide practical insights for the design and optimization of GDL materials. Specifically, controlling tortuosity and its anisotropy can improve reactant transport, enhance efficiency, and increase the durability of fuel cells under realistic operating conditions.

Dynamics of the Subsolar Position of the Earth's Magnetopause during Geomagnetic Storms Originating from CIRs in the Descending Phase of Solar Cycle 24

Boukary Damiba — 2026-05-05

This study focuses on the dynamics of the subsolar position ( , in Earth radii ) of the magnetopause in response to events originating in corotating interaction regions (CIRs) during the declining phase of solar cycle 24. Based on analyses using the models developed by Shue et al. (1998), Liu et al. (2015) and Lin et al. (2010), we quantify the impact of mechanical and electromagnetic couplings on this boundary. We analyse these dynamics based on the north–south component of the interplanetary magnetic field ( B_z, in nT ), the total interplanetary magnetic field strength ( B, in nT ), the dynamic pressure of the solar wind (P_d, in nPa ), and the magnetic pressure (P_m, in nPa ). Additionally, we consider the normalised solar wind–magnetosphere coupling index (N), derived from the Newell et al. (2007) function and scaled by a normalisation factor of 10⁻⁴. Analysis of the temporal profiles across the different phases of the CIR storms studied reveals progressive and oscillatory variations in the magnetopause's subsolar position (R_o ). Our results reveal significant compressions, with a reduction in R_o amplitude ranging from 0.9 R_e to 5 R_e . The main minimum R_o reached during these CIR events studied is 6.4 R_e , pushing the magnetopause below the geosynchronous orbit (6.6 R_e ). The originality of this study lies in the joint application of cross-correlation, Granger causality, and Bootstrap, an approach that allows dissociating the information-contribution delay (Granger causality) from the time required for the maximum physical adjustment of R_o to the various constraints imposed by solar drivers. Granger causality analysis reveals that predictability is not always immediate: while it is instantaneous for certain drivers, it takes between 14 and 21 minutes for past values of to P_d improve the prediction of R_oduring the CIR event of 27 March 2017, and 18 to 20 minutes for the intensity of the interplanetary magnetic field B in the event of 20 January 2016. Regarding physical adjustment, while the responses to and the coupling index (N) are immediate across all six events, the analysis reveals remarkable inertia in the other parameters. The adjustment to the B_z constraint took 33 min to reach its maximum during a specific event. In the six CIR events studied, the adjustment of R_o to the IMF B intensity constraint was slow, with delays ranging from 10 minutes to more than 2 hours (8 min to 130 min). These prolonged delays, particularly well captured by the Lin and Liu models, indicate a hysteresis effect and a slow, global reconfiguration of magnetospheric currents.

Energy Valorization of the Palm Stem: Composition, Potential and Applications in Guinea

Mohamed Lamine Kourouma — 2026-05-02

Biomass derived from palm trees represents a renewable energy resource that remains largely underexploited in Guinea, despite its abundance and local availability. Among its components, the palm stem, or stipe, offers significant energy potential due to its lignocellulosic structure, primarily composed of cellulose, hemicellulose, and lignin, which are key elements for biomass energy valorization. Several studies have shown that this type of biomass exhibits thermochemical properties comparable to those of conventional woody residues commonly used for energy production. This article provides a scientific analysis of the energy composition of the palm stem, its physicochemical properties, and its main valorization pathways, including direct combustion, carbonization, and gasification, while considering the economic, environmental, and energy-specific context of Guinea. The results indicate that, despite a high moisture content in the fresh state, characteristic of tropical biomass, the palm stem exhibits, after proper drying and conditioning, a calorific value comparable to conventional wood. Thus, this biomass represents a credible and sustainable alternative for thermal and electrical energy production, particularly in rural areas of Guinea, where access to centralized grids remains limited and decentralized biomass-based energy solutions offer a strategic lever for local development.