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Abstract Recent literature highlights the potential of animal pollinator-dependent (PD) crops in enhancing food and nutrition security, although there is a lack of detailed household-level estimates. In this study, we investigate the nutrient composition, productivity, and contribution of PD and pollinator-independent (PI) crops to household nutrition in four sub-Saharan African (SSA) countries. We also evaluate the impact of reallocating resources from PI crops to PD crops on nutrient deficiencies, utilizing nationally representative panel data from three waves and over 30,000 household-year observations. Our findings reveal that PD crops exhibit higher micronutrient content per unit, albeit with lower macronutrient content compared to PI crops. PI crops have higher yield of calories per hectare while PD crops have higher vitamin A yield per hectare. However, protein and iron yield for PD and PI crops varies across countries. PI crops predominantly contribute to macronutrients and iron, while PD crops significantly contribute to vitamin A production. Our econometric results demonstrate that increasing the cultivation of PD crops relative to PI crops reduces the prevalence of nutrient deficiencies and increases crop income without compromising macronutrients production. This suggests that greater investment in PD crop production can be an integral approach to achieving nutrition security in SSA.

Abstract This paper presents a QV-based approach called Critical Voltage-Reactive Power Ratio (CVQR) index to assess the voltage instability tendencies of power system buses with increase in renewable energy (RE) penetration within the power system. The buses are thus ranked according to the order in which they are impacted by increase in renewable energy penetration. Simulations were performed using DIgSILENT PowerFactory and result analyses were done with MATLAB. The developed CVQR index has been employed to assess the effect of increasing RE generation on grid voltage stability. This index provides information on the voltage instability tendencies of all non-slack buses of the RE-integrated grid and the buses are ranked from the weakest to the strongest. The rankings obtained from the developed CVQR has been compared with five commonly-used indices and the result of the comparison verifies the accuracy of the proposed index. IEEE 14-bus and IEEE 39-bus New England systems have been used to evaluate the proposed CVQR index and various scenarios of RE system combinations and placements have been considered. Voltage collapse condition is indicated whenever the CVQR index associated with any bus becomes positive (CVQR > 0). This index can as well be applied to other power system networks. The overall ranking of the buses based on the CVQR index can provide insights on the most appropriate location for large inductive loads or compensating devices, which can either absorb or inject reactive power into the power system, thereby influencing the system’s voltage stability.

Abstract This paper investigates the application of large-scale solar photovoltaic (SPV) system for voltage stability improvement of weak national grids. Large-scale SPV integration has been investigated on the Nigerian power system to enhance voltage stability and as a viable alternative to the aged shunt reactors currently being used in the Nigerian national grid to mitigate overvoltage issues in Northern Nigeria. Two scenarios of increasing SPV penetration level (PL) are investigated in this work, namely, centralized large-scale SPV at the critical bus and dispersed large-scale SPV across the weak buses. The voltage stability of the system is evaluated using the active power margin (APM) also called megawatt margin (MWM) derived from Active Power–Voltage (P–V) analysis, the reactive power margin (RPM) and the associated critical voltage–reactive power ratio (CVQR) index obtained from Reactive Power–Voltage (Q–V) analysis. All simulations are carried out in DIgSILENT PowerFactory software and result analyses done with MATLAB. The results show that with centralized SPV generation for the case study system, the highest bus voltage is able to fall within acceptable limits at 26.29% (1000 MW), while the dispersed SPV achieves this at 21.44% (800 MW). Also, the dispersed SPV scenario provides better voltage stability improvement for the system as indicated by the MWM, RPM and the CVQR index of the system. Therefore, this work provides a baseline insight on the potential application of large-scale SPV in weak grids such as the Nigerian case to address the voltage stability problems in the power system while utilizing the abundant solar resource to meet the increasing energy demand.

Abstract The 1,l/-bis(2-phenylethan-1-ol)ferrocene, 1-butyl-3-methylimidazolium hexafluoro phosphate (BMPF6) and NiO-SWCNTs were used to modify carbon paste electrode (BPOFc/BMPF6/NiO-SWCNTs/CPE), which could act as an electro-catalytic tool for the analysis of N-acetylcysteine in this work. The BPOFc/BMPF6/NiO-SWCNTs/CPE with high electrical conductivity showed two completely separate signals with oxidation potentials of 432 and 970 mV for the first time that is sufficient for the determination of N-acetylcysteine in the presence of theophylline. The BPOFc/BMPF6/NiO-SWCNTs/CPE showed linear dynamic ranges of 0.02–300.0 μM and 1.0–350.0 μM with the detection limit of ~ 8.0 nM and 0.6 μM for the measurement of N-acetylcysteine and theophylline, respectively. In the second part, understanding the nature of interaction, quantum conductance modulation, electronic properties, charge density, and adsorption behavior of N-acetylcysteine on NiO–SWCNTs surface from first-principle studies through the use of theoretical investigation is vital for designing high-performance sensor materials. The N-acetylcysteine molecule was chemisorbed on the NiO–SWCNTs surface by suitable adsorption energies (− 1.102 to − 5.042 eV) and reasonable charge transfer between N-acetylcysteine and NiO–SWCNTs.