SDG07 Affordability and clean energy

An energy optimized approach for the design of wireless sensor networks

Thu, 01 Jan 2026 00:00:00 GMT

An energy optimized approach for the design of wireless sensor networks Masopoga, Makwena Idah In today's data-driven world, we need to ensure reliable wireless access as it is vital. The increasing demand for data connectivity has significantly raised power consumption in wireless networks. Wireless Sensor Networks (WSNs), which rely on battery power, face significant challenges due to this vulnerability. WSNs are widely utilized in various applications, including environmental monitoring, healthcare, industrial machinery, and security. Extending their operational lifetime is crucial for ensuring sustainable network performance. The primary limitation of WSNs lies in their energy-constrained nature. As nodes run out of energy, they begin to fail, resulting in reduced network coverage, connectivity, and throughput. While numerous protocols and algorithms have been proposed to extend network lifetime, overcoming power limitations remains a significant challenge. Existing heuristic approaches provide near-optimal solutions but are often impractical for real-time implementation. The goal of this research is to develop and assess energy-efficient algorithms that minimize power consumption and prolong the lifespan of WSNs. The specific objectives are to design an algorithm that optimizes energy usage through efficient routing and clustering, to balance energy consumption among nodes, reducing the likelihood of premature node failures, and to improve network throughput. This study adopts a simulation-based approach to evaluate the proposed algorithm. An energy-aware protocol is implemented to evenly distribute network workload and minimize energy wastage. The research contributes by demonstrating that heuristic solutions can be enhanced to achieve near-optimal performance, closing the gap between offline optimization and practical, real-time deployment. Simulation results indicate that the proposed algorithm improves network lifetime and energy efficiency. Specifically, it achieves over 50% improvement in First Node Death (FND), 14% improvement in Last Node Death (LND), and 37% overall energy savings compared to conventional approaches. These results confirm that better energy balancing significantly enhances WSN sustainability and supports their long-term use across diverse applications.

Measurement of heavy ion induced x-ray production cross sections in metallic targets at MeV energies

Mon, 01 Apr 2019 00:00:00 GMT

Measurement of heavy ion induced x-ray production cross sections in metallic targets at MeV energies Masekane, Masedi Carington Experimental X-ray production cross sections (i.e. probability of X-ray generation in a target by an incoming MeV ion) are useful not only for fundamental ion beam – matter interaction studies, but also for the development of new ion beam materials analysis techniques such as Heavy Ion Particle Induced X-ray Emission (HI-PIXE) spectroscopy. Unfortunately, while theoretical predictions of X-ray production cross sections due to light (Z<6) projectile ions are generally in good agreement with experiment, this is not the same for heavier projectiles. Experimental studies show that heavy ions induce higher X-ray yields in targets compared to light ions of the same velocity, which implies higher sensitivity for Heavy Ion PIXE. There is therefore a need for substantial experimental data to improve theoretical models. This dissertation presents measurements carried out at the iThemba Laboratory for Accelerator Based Sciences (LABS) to determine X-ray production cross sections in Vanadium (V), Zirconium (Zr) and Tin (Sn) metal oxide films due to carbon and chlorine MeV ion beams at an ion velocity range of 0.1-1.0 MeV/u. The measured cross sections are compared to predictions by the modified Plane Wave Born Approximation (PWBA) and the ECPSSR theory that takes into account; the energy loss (E) of the projectile due to Coulomb deflection (C) by the target atom, and the perturbed-stationary state (PSS) and relativistic nature (R) of the target atoms’ inner shell. The observed agreements and discrepancies between experiment and theory are discussed in terms of the atomic ionization mechanisms for each projectile-target collision.

Modeling of the solar radiation output in the Democratic Republic of Congo

Wed, 01 Apr 2026 00:00:00 GMT

Modeling of the solar radiation output in the Democratic Republic of Congo Lusamba Yangindu, Dieudonné The Democratic Republic of Congo is not only a geological contrast but also an energy contrast, as it possesses a great hydroelectric potential capable of satisfying its own needs and those of many African countries. However, according to the most optimistic studies, the electrification rate in the Democratic Republic of Congo is less than 19%. Photovoltaic solar energy therefore represents a viable solution to help meet national energy needs. Accurate knowledge of solar irradiance is essential for proper sizing and optimization of photovoltaic systems. This study aims to establish general statistical models to predict solar irradiance (kWh/m²/day) as a function of sunshine duration (h/day) for any province of the Democratic Republic of Congo. Global solar irradiance data were obtained from RETScreen through the Renewable Energy Atlas of the DRC, while sunshine duration data were collected from the European Centre for Medium-Range Weather Forecasts. Five models (linear, quadratic, cubic, logarithmic, and exponential) were developed using the least squares method and validated using normalized statistical errors (NMAE, NMBE, NRMSE), the Nash–Sutcliffe efficiency criterion (NS), and the coefficient of determination (R²). Two scenarios were analyzed: scenario 1: excluding the provinces of Nord and Sud Kivu, and scenario 2: including these provinces. By excluding these provinces, the quadratic and cubic models explained 88% and 93% of the relationship between annual average sunshine duration and solar irradiance, respectively. Including them reduced performance, with R² ≈ 0.70, indicating that additional climatic variables may be required. A national sunshine duration heat map identifying four main exposure zones was also produced, supporting photovoltaic planning across the Democratic Republic of Congo.

A study of synchronisation in the classical phase-oscillator model of an electrical power grid

Sun, 01 Feb 2026 00:00:00 GMT

A study of synchronisation in the classical phase-oscillator model of an electrical power grid Olivier, Christiaan In this work, we study synchronisation in power grids using a classical phase oscillator model that can be thought of as a variant of the famous Kuramoto model for coupled phase oscillators. In the recent literature, the connection between a Kuramoto-like model and power grids has been made by Filatrella, Nielsen and Pedersen. Here, we will show that this connection goes much further back, to the so-called Classical Model of power grids that was introduced in 1951 by the work of Boast and Rector. We also observe that in 2018, Arinushkin and Anishchenko developed a Kuramotolike model for power grids in which, for the first time, there appear non-negligible phase-lag parameters as a result of the Kron reduced approximation. Although a single phase-lag (or frustration) parameter had been introduced much earlier in the so-called Kuramoto-Sakaguchi model (from 1986), Arinushkin and Anishchenko were the first to introduce multiple phase-lag parameters into a Kuromoto-like model for power grids. Unfortunately, our attempts to replicate their results soon revealed that they used a too-large, fixed time step for the numerical time integration of their equations, and that this led them to make several erroneous conclusions about the grid which they modelled. Therefore, in Chapter 3, we give a detailed critique of the 2018 paper by Arinushkin and Anishchenko. Then, in a follow-up work by Arinushkin and Vadivasova, from 2021, we observe that use was made of nonlinear damping to control the synchronicity of the Kron reduced grid. In this case, we were able to reproduce all the results of Arinushkin and Vadivasova. We were able to develop a more efficient proportional control scheme, based on the global order parameter. Our proposed control scheme and its results were presented at the 2023 International Conference on Electrical, Computer, and Energy Technologies (ICECET). The resulting conference proceeding is included here, in slightly revised form, as Chapter 4. Finally, in Chapter 5, we provide a brief summary of our main findings and some suggestions for future work.