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This paper presents a hybrid Fuel Cell-based Power System (FCPS) consisting of fuel cell and hybrid Energy Storage Systems (ESSs), including a battery with high energy density and supercapacitor with high power density to overcome the sudden load demand change and improving the reliability of the delivered power. Any hybrid power system needs Energy Management Strategies (EMS) to balance the power between the different energy sources. In this paper, a comparative analysis of three energy management strategies, including the state machine control method, the classical PI control method and equivalent consumption minimization strategy (ECMS) is performed. The paper's main objective is enhancing the DC-bus voltage profile of a hybrid fuel cell/battery/supercapacitor power system equipped with the developed under-mentioned EMS by using a hybrid modified optimization technique that combines Harris Hawks optimization (HHO) and Sine Cosine Algorithm (SCA). The new hybrid HHO-SCA is employed to determine the optimal control parameters of the DC-bus voltage controller, which significantly assists in enhancing the DC-bus voltage profile as well as the performance of the applicable ESS in terms of improving efficiency and SoC. The effectiveness of the suggested control schemes is simulated using MATLAB/SIMULINK software. The simulation results confirmed that the proposed HHO-SCA is superior and efficient in improving the DC-bus voltage. • A comparative analysis of three energy management strategies is presented. • New hybrid optimization technique is developed. • Optimal tuning for the control parameters of the DC-bus voltage controller. • Enhancing the DC-bus voltage profile and some performance criteria are conducted. [ABSTRACT FROM AUTHOR]

Abstract The quantitative analysis of 18 parents and their alkyl homologs was performed in sediment samples from the central Arabian Gulf (Gulf) around Qatar Peninsula in six sequential seasons, winter 2014 to spring 2015, at 21 locations with a water depth range of 1.5–60 m. PAHs distribution was patchy with higher concentrations found inside semi-enclosed coastal areas like harbors and bays. The mean PAHs concentration was 112 ng·g−1 dry weight with a range of 0.6 to 1560 ng·g−1 and a variability coefficient of 2.4. The PAHs mean concentration was highest in the winter by a factor of 5 compared to mean summer concentration. A significant seasonal variability in the concentrations of ∑PAHs is mainly attributed to variability in the concentrations of the low molecular weight PAHs fraction and the less alkylated PAHs. Alkylated-PAHs were the most dominant PAHs comprising about 50% of the ∑PAHs, and with about 6 times higher than the mean concentrations in the winter compared to the mean summer concentration. The LPAHs concentrations correlated negatively with temperature and ∑PAHs correlated positively with % clay. Principal component analysis was used to identify sources of PAHs. PAHs in the Gulf have mixed sources with an estimated 57% from petroleum and 43% from pyrogenic sources. Coastal water hydrodynamics and lateral transport processes affect the distribution and composition of PAHs in the central Gulf. Graphical abstract Unlabelled Image Highlights • Levels of 16 PAHs and their alkyls are measured in six seasons in the Gulf. • Radical temperature caused significant loss for LPAHs in summer. • Harbors contained the highest levels of PAHs due to low exchange of water. • PCA analysis indicated that >50% of PAHs in the Gulf comes from petroleum source. • Sediments properties and water current contributed to low PAH in the central Gulf. [ABSTRACT FROM AUTHOR]

Highlights • The SIMULINK models for grid connected PV plants of 100 kW and 1 MW are constructed. • A new GMPPT algorithm based the MFO is proposed as to deal with the problem of PSC. • The GMPPT and DMPPT algorithms combination is used to enhance the PV plant behaviors. • To highlight the MFO dynamic performance, a comparative analysis is carried out. • The obtained results prove that the MFO method gives the best performances under PSC. Abstract The photovoltaic (PV) energy production depends on the conditions surrounding the PV array such as irradiance (G), temperature and the array surface state. These factors directly affect the photonic absorption and the productivity of the PV panels. The phenomenon of partial shading condition (PSC) is one of the problems that disturb the proper operation of PV plants. In the recent literature, several algorithms have been developed to solve this problem. This paper principally aims at extensively presenting the PSC problem that had been considered by numerous articles and cited in this paper. Then, the paper presents combination of two techniques, the first one is the Global Maximum Power Point Tracking (GMPPT) for 100 kW array. The second technique is the Distributed Maximum Power point tracking configuration (DMPPT) for 1 MW PV plant under PSC. This combination aims to overcome the drawbacks related to PSC and enhance the PV system performance. A novel technique GMPPT controller is proposed using Moth-Flame Optimization algorithm (MFO) as solution for PSC shading. A comparative study is performed among different MPPT algorithms such as: Classical Incremental Conductance algorithm (IC), Fuzzy Logic approach based on IC (FL), Particles Swarms Optimization method (PSO) and MFO. Simulation results prove the capability of the proposed approach for seeking the GMPPT of the PV array system. [ABSTRACT FROM AUTHOR]

Experimental study and numerical analysis on the seismic performance of grid tubular-double steel plate (GDSP) concrete composite shear wall subjected to low reversed cyclic loading were carried out in this paper. The effects of axial compression ratio, shear-span ratio, ending-configuration, strength of steel and concrete, length-to-width ratio and aspect ratio of cavity on the seismic performance of GDSP concrete composite shear wall, in terms of hysteresis curve, skeleton curve and failure mode, were investigated. The results show that the GDSP concrete composite shear wall exhibits excellent seismic performance with plump hysteresis curve, high bearing capacity and ductility. With the increase of axial compression ratio, the peak load of GDSP concrete composite shear wall increases, but the ductility decreases gradually. The numerical analysis results are consistent with the results tested. The infilled-concrete is confined by steel plates in three directions, and concrete compressive strength and ductility are significantly enhanced. The concrete sustains the compression together with steel plate, which prevents the outer double steel plate from buckling failure under compression. The length-width ratio of cavity affects the three-dimensional confine effect of the infilled-concrete. It is recommended that the length-width ratio of the end cavity take between 1.0–1.5 and the length to width ratio of the middle cavity set as 1.5–2.0. The single channel steel set at the side of the wall can significantly enhance the bearing capacity and deformation capacity. • The low reversed cyclic loading test is carried out on the grid tubular-double steel plate concrete composite shear wall. • A finite element model is developed to study the hysteresis curve, skeleton curve and failure mode of GDSP shear wall. • The effects of various parameters on seismic performance of grid tubular-double steel plate shear wall are analyzed. [ABSTRACT FROM AUTHOR]