Controlled Fe substitution through the Solid State Synthesis (argon condition) at the B site in the BaMn 1 x FeₓO 3 δ metal oxide system leads to significant improvements in the electrocatalytic activities for both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). When the iron content goes up, the crystal structure changes from hexagonal polytypes (4H BaMnO 3 δ , 10H BaMn 1/2 Fe 1/2 O 3 δ , and 10H BaMn 1/3 Fe 2/3 O 3 δ ) to a monoclinic perovskite type structure in BaFeO 3 δ . This change in structure is accompanied by a significant improvement in electrochemical performance. Compared to Mn rich compositions, BaFeO 3 δ has much lower overpotentials, less charge transfer resistance, higher current densities, and faster reaction kinetics. The results show how important it is to change th e amount of Fe in order to change the electronic structure and catalytic activity of perovskite oxides that are common on Earth. This study demonstrates that the world's second most abundant and cheapest metal, Fe induced structural reorganization, is a vi able approach for the development of high performance catalysts for water splitting, especially in the hexagonal structural framework, which is less investigated.
The energy, exergy and economic analysis of a mixed-mode natural convection solar tunnel dryer for drying banana slices is presented. The collector, drying chamber and chimney energy and exergy are analysed for a load of 3.75 kg of fresh banana slices. Further, the economic analysis in terms of Net Present Value (NPV), Profitability Index (PI), the Payback Period (PB) and the Discounted Payback Period are presented. Drying experiments were done in a period of two days. During the experiment, solar radiation varied from 206.1 W/m2 to 934.5 W/m2; drying chamber temperature varied from 51.7ºC to 81.84ºC while the ambient temperature varied from 21.7ºC to 31.9ºC. The relative humidity ranged from 4.63% to 28.46% for the drying chamber and, 14.9% to 31.8% for the ambient. Under these conditions, the moisture content of the bananas was reduced from 73.89% to 14.27% in seven hours of drying on the first day. Energy and exergy efficiencies ranged from 5.56% to 57.32%, and 0.33% to 2.81%, respectively on Day 1. For Day 2 the energy and exergy efficiencies were from 14.15% to 59.16%, and 0.75% to 3.76%, respectively. For the drying chamber, the efficiency increased gradually in the first two hours to a maximum of 5.36%, corresponding to the period when there was maximum evaporation. The chimney, which is a bare flat plate type without glazing and insulation, lost heat from its surfaces. Nonetheless, it generated enough buoyancy to move air through the dryer. With the solar dryer lifespan of 10 years and the Discounted Payback Period of four years, the project is attractive and worth investing in.
Analyzing from the micro level of the basic unit of environmental protection industry -- enterprise, this paper takes relevant information of more than 8000 key enterprises in China's environmental protection industry from 2018 to 2020 as the big data training samples, and uses BP neural network method to identify the key production factors that have great impact on the output of the whole China's environmental protection industry and its main subdivisions. The results show that China's environmental protection industry is still in the growing stage in the current stage, with significant capital pulling, technological innovation driving, and management innovation also plays an important role. There are differences in the performance of water, air and solid waste in the environmental protection industry. In detail, R&D expenses from the government plays the most important role in water pollution prevention and control industry. Technology innovation plays the most important role in air pollution prevention and control industry. And staff play the most important role in solid waste treatment and resource recycling industry.
The rise of the unconventional oil and gas (UOG) industry over the last two decades has transformed the domestic energy outlook but raised concerns over environmental impacts. With the evolution of Environmental Social Governance (ESG) reporting allowing for a transparent view of oilfield operations, the evaluation of corporate sustainability has become increasingly feasible. Even with increased reporting, there have been very few quantifiable metrics for sustainable water management practices in the UOG industry due to the focus being primarily on methane emissions in recent years. This study aims to provide a practical, quantitative, and concise method (two-parameter based - Quadrant Plot) to evaluate UOG operators' performance in minimizing the negative impacts of freshwater use for drilling and fracking. Parameters (%Freshwater and %Salt Water Disposal) used in this performance matrix have been optimized to gather as much information as possible and while being compatible with operators' existing data collection. This study discusses how the Quadrant Plot could quantify the water performance using private and public data from over 20 unconventional oil and gas operators. This quantitative assessment not only enables the determination of a static performance score but also allows for the depiction of changes in performance over time.
