Facile Fabrication and Developing the Structural,Optical and Electrical Properties of SiC/Y2O3 Nanostructures Doped PMMA for Optics and Potential Nanodevices

Silicon - This work aims to improve the structural, optical and electrical characteristics of silicon carbide(SiC) yttrium oxide(Y2O3) nanostructures doped poly-methyl methacrylate(PMMA) to utilize...     

Imbalance factor: a simple new scale for measuring inter-class imbalance extent in classification problems

Knowledge and Information Systems - Learning from datasets that suffer from differences in absolute frequency of classes is one of the most challenging tasks in the machine learning field. Efforts...     

Thermodynamic and economic evaluation and optimization of the applicability of integrating an innovative multi-heat recovery with a dual-flash binary geothermal power plant

Clean Technologies and Environmental Policy - Generally, a stand-alone flash-binary geothermal power plant loses most of its input energy, so its efficiency declines accordingly. Its overall...     

Seismic damage identification of moment frames based on random forest algorithm and enhanced gray wolf optimization

The present study aims to identify damage in two-dimensional (2-D) moment frames using seismic responses by combining the random forest (RF) machine classifier and the enhanced gray wolf optimizer (EGWO) metaheuristic algorithm. First, a 2-D moment frame for the dynamic analysis is simulated using the finite element method (FEM). Then, the placement of sensors is optimized using a proposed optimal sensor placement (POSP) method, which is a combination of the iterated improved reduced system (IIRS) and the binary differential evolution (BDE) optimization algorithm. The acceleration responses of the moment frame having damaged elements under 1995 Kobe earthquake are measured at the optimal sensor placement. Then, the natural frequencies and mode shapes of the structure are extracted using the auto-regressive model with exogenous input method (ARX) as a system identification method. The natural frequencies are exploited to train an RF machine learning network that can find the damaged story of the moment frame. Then, EGWO is employed to accurately locate and quantify the damaged elements of the structure. The efficiency of the proposed method is assessed through considering a six-story frame with 18 elements, a seven-story frame with 49 elements, and the experimental data of an eight-story frame for various conditions. The results show that the RF algorithm has an outstanding performance to correctly find a damaged story. Furthermore, the location and severity of damaged elements are precisely determined by EGWO algorithm. As a final outcome, it is demonstrated that the two-step proposed method is very effective in seismically identifying damage to such structures.     

Skill Optimization Algorithm: A New Human-Based Metaheuristic Technique

Metaheuristic algorithms are widely used in solving optimization problems. In this paper, a new metaheuristic algorithm called Skill Optimization Algorithm (SOA) is proposed to solve optimization problems. The fundamental inspiration in designing SOA is human efforts to acquire and improve skills. Various stages of SOA are mathematically modeled in two phases, including: (i) exploration, skill acquisition from experts and (ii) exploitation, skill improvement based on practice and individual effort. The efficiency of SOA in optimization applications is analyzed through testing this algorithm on a set of twenty-three standard benchmark functions of a variety of unimodal, high-dimensional multimodal, and fixed-dimensional multimodal types. The optimization results show that SOA, by balancing exploration and exploitation, is able to provide good performance and appropriate solutions for optimization problems. In addition, the performance of SOA in optimization is compared with ten metaheuristic algorithms to evaluate the quality of the results obtained by the proposed approach. Analysis and comparison of the obtained simulation results show that the proposed SOA has a superior performance over the considered algorithms and achieves much more competitive results.     

Influence of Curing Agents Molecular Structures on Interfacial Characteristics of Graphene/Epoxy Nanocomposites: A Molecular Dynamics Framework

This paper presents a comprehensive molecular dynamics study on the effects of the stoichiometric ratio of epoxy:hardener, hardener's linear and cyclic structure, and number of aromatic rings on the interfacial characteristics of graphene/epoxy nanocomposite. The van der Waals gap and polymer peak density as a function of the type of the hardener is calculated by analyzing the local mass density profile. Additionally, steered molecular dynamics are used to conduct normal pull-out of graphene to study the effect of the mentioned features of hardeners on the interfacial mechanical properties of nanocomposites, including traction force, separation distance, and distribution quality of reacted epoxide rings in the epoxy. Influence of the hardeners on the damage mechanism and its initiation point are also studied by analyzing the evolution of local mass density profile during the normal pull-out simulation. It is seen that stoichiometric ratio and geometrical structure of the hardeners affect the interfacial strength. It is also revealed that the hardener type can change the epoxy damage initiation point. The damage occurs in the interphase region for a higher stoichiometric ratio or cyclic structure of hardener. In comparison, for hardener's lower stoichiometric ratio and non-cyclic structure, failure begins in the epoxy near graphene layers.     

Billiards Optimization Algorithm: A New Game-Based Metaheuristic Approach

Metaheuristic algorithms are one of the most widely used stochastic approaches in solving optimization problems. In this paper, a new metaheuristic algorithm entitled Billiards Optimization Algorithm (BOA) is proposed and designed to be used in optimization applications. The fundamental inspiration in BOA design is the behavior of the players and the rules of the billiards game. Various steps of BOA are described and then its mathematical model is thoroughly explained. The efficiency of BOA in dealing with optimization problems is evaluated through optimizing twenty-three standard benchmark functions of different types including unimodal, high-dimensional multimodal, and fixed-dimensional multimodal functions. In order to analyze the quality of the results obtained by BOA, the performance of the proposed approach is compared with ten well-known algorithms. The simulation results show that BOA, with its high exploration and exploitation abilities, achieves an impressive performance in providing solutions to objective functions and is superior and far more competitive compared to the ten competitor algorithms.     

Exploration of Metal Alloys as Zero-Resistance Interfacial Modification Layers for Garnet-Type Solid Electrolytes

A solid-state battery with a lithium-metal anode and a garnet-type solid electrolyte has been widely regarded as one of the most promising solutions to boost the safety and energy density of current lithium-ion batteries. However, lithiophobic property of garnet-type solid electrolytes hinders the establishment of a good physical contact with lithium metal, bringing about a large lithium/garnet interfacial resistance that has remained as the greatest issue facing their practical application in solid-state batteries. Herein, a melt-quenching approach is developed by which varieties of interfacial modification layers based on metal alloys can be coated uniformly on the surface of the garnet. It is demonstrated that with an ultrathin, lithiophilic AgSn_0.6Bi_0.4O_x coating the interfacial resistance can be eliminated, and a dendrite-free lithium plating and stripping on the lithium/garnet interface can be achieved at a high current density of 20 mA cm⁻². The results reveal that the uniform coating on the garnet surface and the facile lithium diffusion through the coating layer are two major reasons for the excellent electrochemical performances. The all-solid-state full cell consisting of the surface modified garnet-type solid electrolyte with a LiNi_0.8Mn_0.1Co_0.1O₂ cathode and a lithium–metal anode maintains 86% of its initial capacity after 1000 stable cycles at 1 C.