There is growing interest in the use of recycled materials in the building sector as a way to reduce waste and improve environmental sustainability. Polyethylene terephthalate (PET) is a thermoplastic polymer that has attracted the attention of researchers due to its application in the building industry. In the recent past, many studies have reported on the application of PET aggregates in structural lightweight concrete. This paper presents a review of the findings of 20 studies conducted between 2010 and 2022 randomly. The preliminary findings highlighted include the method of production of PET aggregates and their physical/thermal properties. The review extended further to focus on the extent of incorporation, physical properties, strength properties, and durability of concrete with PET aggregates. The substitution of PET aggregates up to 20% reflected positively on the compressive strength, while tensile and flexural strength had positive responses up to 10%. Water absorption as a measure of concrete durability increased with the addition of PET aggregates. A meta-analysis of these findings was performed using hypothesis testing (t-test and f-test) to identify significant differences between the experimental outcomes of PET incorporation in concrete. Experimental procedures with greater tolerance for PET inclusion and satisfactory concrete properties were highlighted. The paper recommends the formulation of hybrid mix proportions, developed from experimental designs with noteworthy inclusion of PET aggregates and those that attained high values of desired concrete properties. Furthermore, optimization should be performed to provide robust mix designs for high-strength or lightweight concrete with PET aggregates.

The discrepancy between the operating and design capacities of solar plants in eastern Uganda is alarming; about 35 % underperformance in solar power generation is observed. The goal of the current study is to minimize this disparity by improving the design models. Considering only cell temperature in the power generation model is responsible for the observed difference in design and operational solar power generated, the present study used a thermocouple to directly measure cell temperature, an anemometer to measure wind speed, and a solar power meter to measure irradiance. These extrinsic factors were used to modify the power generation model based only on cell temperature through the direct correlation of cell temperature, wind speed, and irradiance with solar power generation. Thus, the absence of extrinsic factors (wind speed and irradiance) in the design models is responsible for the colossal drop in solar power generated. Empirically, the missing extrinsic factors were used to transform the implicit solar power model into an explicit model. The development of a solar power generation model, multiple differential models, simulation and experimentation with a pilot solar rig served as alternate model for the prediction of solar power generation. The second-order differential model validated well with empirical solar power generated in Busitema, Mayuge, Soroti, and Tororo study areas based on RMSEs (0.6437, 0.6692, 0.2008, 0.1804, respectively), thus, narrowing the gap between the designed and operational solar power generated. Mayuge and Soroti recorded the highest solar power generation of 9.028 MW compared to Busitema (8.622 MW) and Tororo (8.345 MW), suggesting that it has a conducive site for installing future solar plants. The above results support the use of empirical explicit (triple) and second-order differential models for the design and operation of power plants.

The increasing adoption of solar photovoltaic (PV) systems plays a critical role in advancing sustainable energy, particularly in regions with limited or no grid access. However, the long-term performance, reliability, and maintainability of these systems in challenging environments remain a pressing concern. This narrative review investigates key factors impacting the sustainability of solar PV systems, focusing specifically on Uganda's Lango region. The study identifies significant challenges, including harsh environmental conditions, limited availability of certified components, and insufficient maintenance infrastructure, which collectively lead to system inefficiencies and reduced operational lifespans. To address these challenges, the review evaluates strategies such as the implementation of preventive and predictive maintenance practices, capacity-building programs for local technicians, and the introduction of government-supported policies aimed at reducing the cost of quality components. Furthermore, the findings underscore the importance of strengthening local supply chains, promoting community-led maintenance initiatives, and expanding technical support networks. The study concludes that a multi-pronged approach integrating technical, policy, and community-driven solutions is vital for enhancing the resilience, viability, and longevity of solar PV systems in resource-constrained settings. These recommendations offer actionable pathways to ensure sustained energy access and foster the broader adoption of solar PV technology in underserved regions.