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AbstractRecently, modern power systems depend heavily on MicroGrids (MGs), which can accommodate Distributed Energy Resources (DERs) economically and with high flexibility. MGs integrated with DERs can assist in enhancing energy security, significant cost savings, and reduction in emission of greenhouse gases. In this paper, the assessment of operating performance of proposed MG system with DERs is employed to investigate the multi‐objective problems of cost optimization and economic scheduling. A grid‐connected Micro‐grid (MG) combined with solar photovoltaic (PV), wind turbine (WT), fuel cell (FC), and Battery Energy Storage System (BESS) is implemented to model the problem. This proposed model is considered as a test system for cost optimization and battery charging/discharging optimization. The developed framework is presented as multi‐objective function with constraints that can be tackled using an effective optimization technique. The above stochastic multi‐objective problem is optimized using various commonly used Physics based Meta‐heuristic techniques such as Simulated Annealing (SA), Harmony Search (HS), Slime Mold Algorithm (SMA), Gravitational Search Algorithm (GSA), Black Hole Optimization (BHO), Sine Cosine Algorithm (SCA), Multiverse optimization (MVO) and Lightning Search Algorithm (LSA). The assessment of the aforementioned physics‐based optimization techniques used on the proposed MG test system is compared using the results. According to the analysis, Black Hole Optimization (BHO) and Lightning Search Algorithm (LSA) both provide greater cost savings overall and for battery charging, respectively. The suggested optimization methods will take the BESS charging/discharging pattern and total cost savings into account.

Polymer-based multicolor emissive materials have growing demand due to their potential applications in various fields such as full-color displays, bioimaging, and light sources because of their processability and high stability. Herein, we report dual-color emissive hybrid materials based on biocompatible poly(l-lactide) and polyethylene glycol-modified two-dimensional layered double hydroxide quantum dots (PEG-LDHQDs). The morphology of polymer films tunes the spatial distribution of QDs within the polymer matrix, modulating the energy transfer between the QDs and affording the dual emission behavior in the aggregated states. The amorphous hybrid films show single emission (blue) from the finely dispersed QDs (mostly isolated) within the polymer matrix. In contrast, dual emission (blue and red) was observed when the polymer was crystallized due to the possible accumulation of QDs at the interface of crystalline and amorphous phases in the lamellar structure. Furthermore, the dual emission could be enhanced by the aggregation of QDs on the pores of the breath figure pattern constructed on the surface of the hybrid film.

In this paper, a comparison of power system frequency response is conducted for a simple modelled power system with primary frequency control being provided either by synchronous generators or by inverter-based Battery Energy Storage (BES) systems. Mathematical models of conventional governor and turbine are developed, representing conventional synchronous generator frequency control, and are used to illustrate system frequency response for a range of typical conventional generating units. A mathematical model of a power-electronics interfaced Li-ion BES system is developed and used to represent a non-synchronous inverter-based generator with primary frequency control capabilities. MATLAB/Simulink is used to build a model of a small power system, and simulations are carried out with at a range of typical conventional synchronous generating units with a nonsynchronous generating unit in the power system. The simulation results demonstrate that the BES can be used for primary frequency control providing a faster and better response. BES is also capable of almost eliminating frequency overshoot and reducing 70% of settling time while providing primary frequency control in power system with various types of conventional synchronous generating units and a nonsynchronous generating unit.

AbstractIn the present study, effect of internals and other hydrodynamic variables on pressure drop and expansion ratio were examined. The parameters studied include inlet air flow rate, bed height, spacing of internal, column diameter and percentage open area. Disc promoters of three different percentages of open area (48.03%, 55.15%, 66.26%) were used. The pressure drop was found to increase significantly with increase in bed height and decrease with open area of internals. As the spacing was decreased, the pressure drop increased first and then decreased due to effective breaking of bubbles in the presence of internals. The expansion ratio was seen to decrease significantly with decrease in the internal spacing and decrease in open area of internals. Correlations for pressure drop and expansion ratio have been found using dimensional analysis. The calculated values of pressure drop and expansion ratio were compared with experimental values. Several models have been developed using the Artificial Neural...

Abstract To improve the conversion efficiency of thermophotovoltaic devices, we designed a thermophotovoltaic system based on an InAs/InGaAsSb/GaSb three-junction tandem cell. The tandem cell can recover photons in the wavelength range of 200–3650 nm and therefore enhance the output power of the system. To further improve system performance, we designed a multilayer circular truncated cone metamaterial emitter matching the tandem cell. Existing TPV systems based on multi-junction tandem PV cells can achieve conversion efficiencies of 33.3%–41%, while the thermophotovoltaic system coupled with the multilayer circular truncated cone metamaterial can recover more photons of 1.44 mol/(m2·s) and achieve a higher conversion efficiency of 52.8% at 1773 K. The thermophotovoltaic system designed here demonstrates an extremely high energy conversion efficiency and has good application prospects.

Heat stress and cold stress have a negative influence on cattle welfare and productivity. There have been some studies investigating the influence of cold stress on cattle, however the emphasis within this review is the influence of heat stress on cattle. The impact of hot weather on cattle is of increasing importance due to the changing global environment. Heat stress is a worldwide phenomenon that is associated with reduced animal productivity and welfare, particularly during the summer months. Animal responses to their thermal environment are extremely varied, however, it is clear that the thermal environment influences the health, productivity, and welfare of cattle. Whilst knowledge continues to be developed, managing livestock to reduce the negative impact of hot climatic conditions remains somewhat challenging. This review provides an overview of the impact of heat stress on production and reproduction in bovines.

AbstractIn the present study, we analyze a field-based seven-year data series of surface mass-balance measurements collected during 2011/12 to 2017/18 on Naradu Glacier, western Himalaya, India. The average annual specific mass balance for the said period is − 0.85 m w.e. with the maximum ablation of − 1.15 m w.e. The analysis shows that the topographic features, south and southeast aspects and slopes between 7 to 24 degrees are the reasons behind the maximum ablation from a particular zone. The causes of surface mass balance variability have been analyzed through multiple linear regression analyses (MLRA) by taking temperature and precipitation as predictors. The MLRA demonstrates that 71% of the observed surface mass balance variance can be explained by temperature and precipitation. It clearly illustrates the importance of summer temperature, which alone explains 64% variance of surface mass balance. The seasonal analysis shows that most of the surface mass balance variability is described by summer temperature and winter precipitation as two predictor variables. Among monthly combinations, surface mass balance variance is best characterized by June temperature and September precipitation.