The increasing demand for Prunus africana resources is an opportunity for its conservation and commercial use to support livelihoods in Africa. The objective for this study was to investigate major steps to advance production of P. africana for long-term commercial use in Uganda. Specific objectives were to explore potential production schemes, setbacks in production and strategies to advance it. The study was done by review of literature, documents and interviews with experts. Results indicated Agroforestry and large plantations to be useful schemes for production. Identified setbacks are: low trade in P. africana, unknown returns from production, competing land uses, long growth period, limited market assurance and information. The lack of a resource assessment for P. africana in forests contributes to its low trade which undermines related economic benefits for national development and incentives to commercial production. We propose that a national Quantitative resource assessment of P. africana in forests is one of the crucial steps that should be undertaken to carefully organise and advance sustainable trade to provide rational incentives for commercial production. Subsequently, production should be localised in suitable sites and producers be organised into cooperatives. Further research to improve returns from commercial production of P. africana is needed.
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This paper assesses wind resource characteristics and energy yield for micro wind turbines integrated on noise barriers. An experimental set-up with sonic anemometers placed on top of the barrier in reference positions is realized. The effect on wind speed magnitude, inflow angle and turbulence intensity is analysed. The annual energy yield of a micro wind turbine is estimated and compared using data from a micro-wind turbine wind tunnel experiment and field data. Electrical energy costs are discussed as well as structural integration cost reduction and the potential energy yield could decrease costs. It was found that instantaneous wind direction towards the barrier and the height of observation play an influential role for the results. Wind speed increases in perpendicular flows while decreases in parallel flow, by +35% down to −20% from the reference. The azimuth of the noise barrier expressed in wind field rotation angles was found to be influential resulted in 50%–130% changes with respect to annual energy yield. A micro wind turbine (0.375 kW) would produce between 100 and 600 kWh annually. Finally, cost analysis with cost reductions due to integration and the energy yield changes due to the barrier, show a LCOE reduction at 60%–90% of the reference value. https://doi.org/10.1016/j.jweia.2020.104206
Assigning gates to flights considering physical, operational, and temporal constraints is known as the Gate Assignment Problem. This article proposes the novelty of coupling a commercial stand and gate allocation software with an off-the-grid optimization algorithm. The software provides the assignment costs, verifies constraints and restrictions of an airport, and provides an initial allocation solution. The gate assignment problem was solved using a genetic algorithm. To improve the robustness of the allocation results, delays and early arrivals are predicted using a random forest regressor, a machine learning technique and in turn they are considered by the optimization algorithm. Weather data and schedules were obtained from Zurich International Airport. Results showed that the combination of the techniques result in more efficient and robust solutions with higher degree of applicability than the one possible with the sole use of them independently.
