Tuning the band gap of the CIGS solar buffer layer Cd1-xZnxS (x=0—1) to achieve high efficiency

To evaluate the impact of zinc sulfate (ZnSO4) concentration on the structural properties of the films, Cd1-xZnxS thin films were formed on glass substrates using chemical bath deposition (CBD) in this study. The effect of ZnSO4 precursor concentration on the surface morphology, optical properties, and morphological structure of the Cd1-xZnxS films was investigated. To study the impact of zinc doping content on the performance metrics of Cu(In1-xGax)Se2 (CIGS) cells in the experimental group and to improve the buffer layer thickness, simulations were run using one-dimensional solar cell capacitance simulator (SCAPS-1D) software.     

Structural, electrochemical and cycling properties of Nb5+ doped LiNi0.8Co0.1Mn0.1O2 cathode materials at different calcination temperatures for lithium-ion batteries

LiNi0.8Co0.1Mn0.1O2 cathode material is prepared by sol-gel method and the effects of Nb5+ doping and different calcination temperatures on cathode materials were deeply investigated. Structural and morphological characterizations revealed that the optimal content of 1 mol% Nb5+ can stabilize layered structures, mitigate Ni2+ migration to Li layers, improve lithium diffusion capacity, and reduce lattice expansion/shrinkage while cycling. And calcination temperature at 800 °C can not only ensure good morphology, but also suppress the mixed discharge of lithium and nickel in the internal structure. Electrochemical performance evaluation revealed that Nb5+ doping improves the discharge-specific capacity of the material, which is conducive to ameliorating its rate capability and cycle performance. And the material at 800 °C exhibits the highest discharge specific capacity, the best magnification performance, low polarizability, and the best cycle reversibility.     

A neural network controller for load following operation of nuclear reactors

Nuclear reactors are in nature nonlinear and their parameters vary with time as a function of power level, fuel burnup, and control rod worth. Therefore, these characteristics must be considered if large power variations occur in power plant working regimes (for example in load following conditions). In this paper a neural network controller (NNC) is presented. A robust optimal self-tuning regulator (ROSTR) response is used as a reference trajectory to determine the feedback, feedforward and observer gains of the NNC. The NNC displayed good stability and performance for a wide range of operation as well as considerable reduction in computation time in regard to ROSTR and fuzzy logic controller (FAROC).     

Effect of preheating and annealing temperature on the microstructure and optoelectronic properties of CZTS films prepared by sol-gel method

The effects of different preheating and annealing temperatures on the surface morphology, microstructure, and optical properties of Cu2ZnSnS4 (CZTS) thin films are investigated by controlling the preheating and annealing temperatures. The prepared thin films were characterized using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and ultra-violet-visible (UV-Vis) spectroscopy techniques. XRD and Raman spectroscopy showed that a Kesterite structure with a selective orientation along the (112) peak was generated, and the thin films produced at a preheating temperature of 300 °C and annealing temperature of 570 °C had fewer secondary phases, which was beneficial for improving the performance of the solar cells. SEM confirms that the crystallite size increases and then decreases as the temperature increases, and the largest and most uniform crystallite size with the smoothest surface is generated at the above preheating and annealing temperatures. UV-Vis measurements show that the thin films generated at the above temperature have the lowest transmittance and the lowest optical band gap value of 1.46 eV, which is close to the optimal band gap value for solar cells and is suitable as an absorber layer material.     

Enhanced functionality of Scots pine sapwood by in situ hydrothermal synthesis of GdPO4·H2O:Eu3+ Composites in woods matrix

Luminescent lanthanide-doped phosphates have never been introduced as potential materials for wood functionalization. Wood–ceramic composites (WCC) may enable the extensive use of wood in construction due to different functionalization. Hence, this work proposes the inorganic GdPO₄·H₂O:Eu³⁺ compound as an alternative and innovative method to increase wood chemical resistance and confer new optical properties. Scots pine (Pinus sylvestris L.) sapwood – ceramic composite was obtained through in situ hydrothermal synthesis and compared with the untreated sapwood specimens. The enhanced characteristics of the WCC samples were demonstrated using scanning electron microscopy (SEM), x-ray computed micro-tomography (μCT), and thermogravimetric (TG) analysis. Optical properties were determined by luminescence analysis.     

Untangling parameters: A formalized framework for identifying overlapping design parameters between two disciplines for creating an interdisciplinary parametric model

Employing an interdisciplinary approach in design is an important part of the future of architecture. Therefore, taking a step toward better understanding the overlaps between disciplines, and formalizing the process of integration between disciplines accelerates progress in the field. In examining an interdisciplinary design approach using computational design and simulation tools, while considering shell structures as a special case for spanning large-span roofs, structural and daylighting discipline are considered. The aim is to understand what are the design parameters that co-exist in the structural and daylighting design disciplines, and how may these parameters be implemented in a parametric model created by designers. The parametric model that includes discipline specific parameters can later be used for interdisciplinary performance-based design. Implementing design parameters calls for an understanding of the ways in which parameters affect design and performance. This research considers the application of parametric design methods at the early stages of design for designing high-performance buildings.     

Improvement of maximum power point tracking in photovoltaic arrays in different environments using hybrid algorithms

When the photovoltaic(PV) system is generating PV power, the partial shading(PS) condition will cause multiple peaks in the power-voltage curve, and changes in light intensity and ambient temperature will cause the curve to shift. Traditional maximum power point tracking(MPPT) methods, such as the incremental conductance(INC) method, have the problem of being trapped in the local optimal solution. Biomimetic optimization algorithms, such as particle swarm optimization(PSO), have problems with os...     

Effect of complexing agent concentration on properties of CdZnS thin films in ammonia-thiourea system

In this paper, the effects of different concentrations of complexing agent (ammonia) on the surface morphology, composition, structure and photoelectric properties of CdZnS films were studied. The results of X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible spectrum showed that the surface morphology of the films became worse and the content of zinc decreased significantly with the increase of ammonia concentration. The crystalline phase of CdZnS films was not influenced by the ammonia concentration. Because the film has good absorbance, transmittance greater than 70% and band gap width between 3.5 eV and 3.07 eV, it is suitable to be used as a buffer layer for solar cells. CdS, ZnO and Zn(OH)2 were found in the precipitates at the bottom of the solution, and the formation of these precipitates affected the properties of the CdZnS films.     

A survey of distributed optimization

In distributed optimization of multi-agent systems, agents cooperate to minimize a global function which is a sum of local objective functions. Motivated by applications including power systems, sensor networks, smart buildings, and smart manufacturing, various distributed optimization algorithms have been developed. In these algorithms, each agent performs local computation based on its own information and information received from its neighboring agents through the underlying communication network, so that the optimization problem can be solved in a distributed manner. This survey paper aims to offer a detailed overview of existing distributed optimization algorithms and their applications in power systems. More specifically, we first review discrete-time and continuous-time distributed optimization algorithms for undirected graphs. We then discuss how to extend these algorithms in various directions to handle more realistic scenarios. Finally, we focus on the application of distributed optimization in the optimal coordination of distributed energy resources.