South Eastern Kenya University "SEKU" is a public university with its main campus located in Kwa Vonza, Kitui County, Kenya.It was formerly South Eastern University College "SEUCO", a constituent college of The University of Nairobi prior to its award of Charter in 2013.The Vice Chancellor of SEKU is Prof. Geofrey M. Muluvi.
High-purity germanium (HPGe) detectors are essential for high-resolution gamma-ray spectroscopy in high-energy physics (HEP, e.g., 50 keV–10 MeV), neutrino physics, and rare event searches. However, their performance is often limited by charge trapping, non-uniform electric fields, and material inhomogeneities. This is particularly for interactions occurring at greater depths within the detector. Our paper proposes a simulation idea to understand the interactions, while the detection depth is changed. The aim is to improve charge collection efficiency (CCE) for HEP applications. To confirm this model, we used a p-type HPGe detector with a z-direction doping gradient. The simulation models a 20-mm-long, 15-mm-radius HPGe crystal. The contacts assume the standard fabrication processes of lithium-ion diffusion and boron-ion implantation for both n⁺ and p⁺ contacts, respectively. An impurity gradient, increasing along the z-axis, is credited for enhanced internal electric field at greater detector depths. This improves carrier drift and reduces trapping losses. Using the isotropic charge carrier model and Boggs trapping model at 78 K, the simulation predicts near-complete CCE in deeper regions, where conventional uniform doping fails. Experimentally, a p-type HPGe detector, similar to the simulated one and cooled by liquid nitrogen, is evaluated using non-collimated gamma-ray sources (241Am, 57Co, 137Cs, 60Co) at 5.7 cm and 9.6 cm source-to-detector distances. The results show high efficiency and resolution for shallow, low-energy interactions, but significant efficiency loss for deeper, high-energy gamma rays. These findings validate the simulation and highlight the benefits of depth-engineered doping for optimizing CCE.
The urgent challenge of climate change calls for innovative energy solutions that reduce greenhouse gas emissions and strengthen system resilience. Solar thermal technology, when enhanced by advanced fluid dynamics, offers a promising pathway towards sustainable clean energy. This study simulates the performance of hybrid nanofluids, specifically copper and titanium dioxide nanoparticles dispersed in water, to improve heat transfer efficiency in parabolic solar thermal collectors. The governing nonlinear partial differential equations describing mass, momentum, energy, concentration, and magnetic induction are reduced to ordinary differential equations using similarity transformations and solved using MATLAB's collocation based bvp4c solver. The model assumes two-dimensional laminar flow, thermal equilibrium between fluid phases, and temperature dependent hybrid nanofluid properties. Parametric analysis shows that Brownian diffusion and thermophoresis significantly influence velocity, temperature, and nanoparticle concentration, while Prandtl and thermal Grashof numbers strongly govern convective transport and MHD coupling. The findings provide deeper physical insight into hybrid nanofluid dynamics under electromagnetic influences and support the optimization of solar thermal collectors for enhanced thermal performance. The study contributes to Sustainable Development Goals 13 by advancing efficient and climate resilient clean energy technologies.
The agricultural sector, a vital industry for human survival and a primary source of food and raw materials, faces increasing pressure due to global population growth and environmental strains. Productivity, efficiency, and sustainability constraints are preventing traditional farming methods from adequately meeting the growing demand for food. Precision farming has emerged as a transformative paradigm to address these issues. It integrates advanced technologies to improve decision making, optimize yield, and conserve resources. This approach leverages technologies such as wireless sensor networks, the Internet of Things (IoT), robotics, drones, artificial intelligence (AI), and cloud computing to provide effective and cost-efficient agricultural services. Smart sensor technologies are foundational to precision farming. They offer crucial information regarding soil conditions, plant growth, and environmental factors in real time. This review explores the status, challenges, and prospects of smart sensor technologies in precision farming. The integration of smart sensors with the IoT and AI has significantly transformed how agricultural data is collected, analyzed, and utilized to optimize yield, conserve resources, and enhance overall farm efficiency. The review delves into various types of smart sensors used, their applications, and emerging technologies that promise to further innovate data acquisition and decision making in agriculture. Despite progress, challenges persist. They include sensor calibration, data privacy, interoperability, and adoption barriers. To fully realize the potential of smart sensors in ensuring global food security and promoting sustainable farming, the challenges need to be addressed.
There is a decline in crop yields due to climate change. Drought and low-soil-fertility-tolerant crops could enhance food production. The objective of this study was to assess the effects of rainfall patterns and soil properties on yields of sorghum landraces. Rainfall and yield data were obtained from the Ministry of Agriculture and the meteorological department. Soil properties from farmers' farms and experimental sites were determined. Experiments were laid out in a Randomized Complete Block Design. Accessions were grown in selected locations in the Eastern, Nyanza and Coastal regions. Data were subjected to analysis of variance using R statistical software. Reduced rainfall periods recorded low yields. However, on station (2019), yields were higher, though rainfall was very low. Farmers' farms recorded pH (6.3–6.8), OC (0.6–1.2%), phosphorus (36.5–50.0ppm), nitrogen (0.1–0.2%) and potassium (1.1–1.6 Cmol/kg). Sodium was highest in the east (0.8 Cmol/kg), calcium (4.0 Cmol/kg), and magnesium (1.4 Cmol/kg) in Nyanza. Manganese and copper were highest in Nyanza, while high iron and zinc were observed in eastern and coastal regions, respectively. At planting, Taita Taveta farm recorded significantly high nitrogen, whereas phosphorus and calcium were highest in KALRO Katumani. Kitaakya ivuui Makueni (b) and Nyakabala Siaya (a) performed best in at least two regions. Though rainfall had an impact on yields, optimum agronomic practices and accession yield potential increased yields under low rainfall. Low on-farm yields could be attributed to low organic carbon and nitrogen. Use of accessions with high yield potential could enhance food security under low moisture and nutrient-depleted soils.
Marine pollution threatens ocean ecosystems and human health through eutrophication, bioaccumulation, and habitat degradation. This article discusses chemical contaminants, nutrient pollution and eutrophication, marine debris, ocean noise pollution, global and regional hotspots of ocean pollution, the impact of pollution on marine biodiversity, mitigation strategies and global effects, restoration and cleanup efforts, and challenges and future outlooks in marine pollution. The excess nutrient levels disturb ecological balances, cause harmful algal blooms, and threaten biodiversity and coastal economies. While plastic pollution has received widespread attention, marine debris also includes non-plastic materials such as metal, glass, rubber, and textiles. Ocean noise pollution, primarily from shipping, seismic exploration, and military sonar, significantly disrupts marine ecosystems by interfering with the communication, navigation, and behavioral patterns of marine species. The buildup of plastic gyres such as the Great Pacific Garbage Patch is a key contributor to global ocean pollution. Remote polar regions can also show significant accumulation of pollutants due to long-distance marine and atmospheric transportation. Multi-faceted and integrated approaches, such as global regulatory frameworks, technological innovation, waste management improvement, and public engagement, are required to decrease ocean pollution. The growing awareness of marine pollution, especially for plastic debris, has fueled the pick-up trash before it disperses into the open ocean. Meanwhile, ecosystem restoration, ranging from mangrove replanting to coral reef rehabilitation, is crucial in rebuilding degraded marine habitats and promoting resilience to subsequent environmental and climatic pressures.
