Metal oxide materials are known for their ability to store thermochemical energy through reversible redox reactions. Metal oxides provide a new category of materials with exceptional performance in terms of thermochemical energy storage, reaction stability and oxygen-exchange and uptake capabilities. However, these characteristics are predicated on the right combination of the metal oxide candidates. In this study, metal oxide materials consisting of pure oxides, like cobalt(II) oxide, manganese(II) oxide, and iron(II, III) oxide (Fe₃O₄), and mixed oxides, such as (100 wt.% CoO, 100 wt.% Fe₃O₄, 100 wt.% CoO, 25 wt.% MnO + 75 wt.% CoO, 75 wt.% MnO + 25 wt.% CoO) and 50 wt.% MnO + 50.wt.% CoO), which was subjected to a two-cycle redox reaction, was proposed. The various mixtures of metal oxide catalysts proposed were investigated through the thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), energy dispersive X-ray (EDS), and scanning electron microscopy (SEM) analyses. The effect of argon (Ar) and oxygen (O₂) at different gas flow rates (20, 30, and 50 mL/min) and temperature at thermal charging step and thermal discharging step (30–1400 °C) during the redox reaction were investigated. It was revealed that on the overall, 50 wt.% MnO + 50 wt.% CoO oxide had the most stable thermal stability and oxygen exchange to uptake ratio (0.83 and 0.99 at first and second redox reaction cycles, respectively). In addition, 30 mL/min Ar–20 mL/min O₂ gas flow rate further increased the proposed (Fe,Co,Mn)Ox mixed oxide catalyst’s cyclic stability and oxygen uptake ratio. SEM revealed that the proposed (Fe,Co,Mn)Ox material had a smooth surface and consisted of polygonal-shaped structures. Thus, the proposed metallic oxide material can effectively be utilized for high-density thermochemical energy storage purposes. This study is of relevance to the power engineering industry and academia.

Health impact assessments of ambient particulate matter remain far less developed in sub-Saharan African cities, despite fine particulate matter (PM_2.5) being a significant contributor to premature mortality globally. This study quantified the public health burdens of adult mortality associated with long-term PM_2.5 exposure in Addis Ababa, Ethiopia, under different counterfactual air quality scenarios. Hourly PM_2.5 data were collected across nine monitoring stations from 2022 to 2023. AirQ+ tool was utilized to estimate attributable natural-cause and cardiovascular disease (CVD) mortality among adults aged ≥ 30 years. Spatial analysis showed mean concentrations ranging from 15 µg/m³ to 33 µg/m³, with an overall mean of 26.74 µg/m³, exceeding the WHO annual guideline by more than fivefold. Seasonal peaks occurred from June to August and diurnal maxima at 7:00 AM. In 2022, attributable natural-cause deaths ranged from 1489 (6.16%) at the less stringent WHO Interim Target 3 (15 µg/m³) to 3169 (13.11%) at the WHO Air Quality Guidelines (5 µg/m³). In 2023, the range was 1544 (6.40%) to 3218 (13.33%). For specific chronic endpoints, PM_2.5 concentration level was responsible for between 509 and 1071 CVD deaths in 2022, and between 535 and 1126 CVD deaths in 2023 across the counterfactual scenario. These results highlight the substantial health burden posed by ambient PM₂.₅ in Addis Ababa and emphasize the urgent need for targeted interventions.

Traffic police officers represent a critical occupational group with high vulnerability to vehicular air pollution, a severe environmental health threat in rapidly urbanizing metropolises such as Addis Ababa. This cross-sectional study explored occupational exposure, protective practices, health risks, perceptions, and awareness of air-quality-associated health risks among 120 traffic police officers in Addis Ababa. The officers were mostly male (80%) and married (93.3%), with the majority (62.6%) having served for more than ten years. While vehicle emissions were consistently recognized as the main source of air pollution, critical knowledge gaps were identified, i.e., only 24.2% had received pollution-related training, fewer than half (45.8%) were aware of government policies, and just 9.2% reported collaboration with environmental authorities. Awareness of the Air Quality Index (AQI) was generally low, and regular monitoring of AQI was limited. Self-reported health symptoms were highly prevalent among participants, with cough (75.0%), eye irritation (61.7%), sneezing (58.3%), and runny nose (55.8%) being the most frequently reported. Notably, sneezing, runny nose, eye irritation, and psychological stress showed significant association with perceived pollution levels at the workplace (p < 0.05), while blood pressure, cough, difficulty concentrating, and sleep loss were not significantly associated (p > 0.05). A higher prevalence of symptoms was generally observed in groups experiencing moderate-to-very high levels of pollution. Protective measures were applied inconsistently; while 63.3% of participants reported using masks, their beliefs about the effectiveness of using masks varied. Relocation (60%) and use of face covers/glasses (13.3%) were less commonly practiced. Overall, traffic police officers are exposed to occupational air pollution, which is associated with various health symptoms. These findings highlight the need for enhanced training, clearer communication of policies, stronger institutional engagement, the provision of standardized protective masks, and the promotion of AQI utilization to reduce occupational health risks and safeguard the wellbeing of traffic police officers in Addis Ababa.

The Upper Blue Nile Basin (UBNB) in Ethiopia has a huge hydropower development potential and it covers a considerable amount of the present hydropower consumptions in the country. However, as hydropower is basically rainfall-dependent, its future sustainable utilization under climate change is highly uncertain. As a result, it is critical to identify the amount of wind energy that can be harnessed in the area since wind is a good substitute for hydropower. Nonetheless, wind energy suitability studies and potential estimations are rarely researched in the UBNB. The objective of this study is, therefore, to investigate wind farm suitability based on multi-criteria decision method using Geographic Information System (GIS) and to determine the energy potentials of those suitable areas in UBNB. Wind speed, slope, land use/land cover, distance from grids, roads, urban areas, and protected areas were considered to identify suitable wind farm sites. The relative weights of these factors were calculated and overlaid by the principle of pairwise comparison in the context of the Analytic Hierarchy Process. From the total area it was found that 1498.69 km2 was highly suitable. The suggested highly suitable areas for wind farm sites fall in the northeastern part of the study area. For wind power potential investigation, wind speed data of ten sites with 15 min intervals of four years (2017-2020) were accessed from National Meteorology Agency (NMA). And it was statistically analyzed using statistical methods and software like MS-Excel and MATLAB programs. The best Weibull parameters estimator was identified based on the statistical test results for each station. From the wind power density analysis using 15-minute interval wind speed, the highest wind power density was recorded in Wogeltena followed by Gatira. Finally, the power density was higher during dry and short rainy season and can be said that wind is a good complementary to hydropower. In conclusion, most of the wind speed data in this study were not enough for wind energy potential estimations at large scales. This may be because the meteorological stations in the study area may not be located at ideal places for wind energy potential estimations. Thus, different wind speed measuring tools (i.e. taller wind mast) are suggested for additional wind energy potential investigations. Relatively, the northeastern parts of the study area are the most promising sites discovered in this study. Hence, these areas might be regarded as feasible for various wind energy applications (i.e. grid-connected and stand-alone).