Boundary Strategy for Optimization-based Structural Damage Detection Problem using Metaheuristic Algorithms

The present paper proposes a new strategy namely Boundary Strategy (BS) in the process of optimization-based damage detection using metaheuristic algorithms. This strategy gradually neutralizes the effects of structural elements that are healthy in the optimization process. BS causes the optimization method to find the optimum solution better than conventional methods that do not use the proposed BS. This technique improves both aspects of the accuracy and convergence speed of the algorithms in identifying and quantifying the damage. To evaluate the performance of the developed strategy, a new damage-sensitive cost function, which is defined based on vibration data of the structure, is optimized utilizing the Shuffled Shepherd Optimization Algorithm (SSOA). Different examples including truss, beam, and frame are investigated numerically in order to indicate the applicability of the proposed technique. The proposed approach is also applied to other well-known optimization algorithms including TLBO, GWO, and MFO. The obtained results illustrate that the proposed method improves the performance of the utilized algorithms in identifying and quantifying of the damaged elements, even for noise-contaminated data

A Physics-based Metaheuristic Algorithm Based on Doppler Effect Phenomenon and Mean Euclidian Distance Threshold

Doppler Effect (DE) is a physical phenomenon observed by Doppler, an Austrian mathematician, in 1842. In recent years, the mathematical formulation of this phenomenon has been used to improve the frequency equation of the standard Bat Algorithm (BA) developed by Yang in 2010. In this paper, we use the mathematical formulation of DE with some idealized rules to update the observer velocity existing in the Doppler equation. Thus, a new physics-based Metaheuristic (MH) optimizer is developed. In the proposed algorithm, the observers’ velocities as the algorithm’s search agents are updated based on the DE equation. A new mechanism named Mean Euclidian Distance Threshold (MEDT) is introduced to enhance the quality of the observers. The proposed MEDT mechanism is also employed to avoid the locally optimum solutions and increase the convergence rate of the presented optimizer. Since the proposed algorithm simultaneously utilizes the DE equation and MEDT mechanism, it is called the Doppler Effect-Mean Euclidian Distance Threshold (DE-MEDT) metaheuristic algorithm. The proposed DE-MEDT algorithm’s efficiency is evaluated by solving well-known unconstrained and constrained optimization problems. In the unconstrained optimization problems, 23 well-known optimization functions are used to assess the exploratory, exploitative, and convergence behaviors of the DE-MEDT algorithm

Liquid-Assisted Mechanochemical Synthesis of LiI-Doped Sulfide Glass Electrolyte

Inorganic solid electrolytes (ISEs) gain tremendous attention during the past decade for application in energy storage. Among different classes of ISEs, sulfides are particularly appealing due to their higher ionic conductivity, ductility, and lower density compared with oxides. However, most of the preparation methods proposed so far require either the time-consuming mechanical ball-milling process or the energy-consuming high-temperature solid-state reaction. Herein, a new and fast liquid-assisted approach to synthesize LiI-doped glassy Li$_{2}$S-P$_{2}$S$_{5}$ (LPS) with excellent electrochemical and morphological features is reported. The obtained solid electrolyte offers an ionic conductivity of 1.2 mS cm$^{-1}$ at room temperature and establishes a rather stable interphase with lithium. These enable rather high critical current densities (up to 1 mA cm$^{-2}$), as well as enhanced cathode active material utilization in solid-state lithium metal cells

High loading CuS-based cathodes for all-solid-state lithium sulfur batteries with enhanced volumetric capacity

Transition metal sulfides have shown to improve the performance of lithium-sulfur batteries both with liquid and solid electrolytes. In this work, the beneficial effect of copper sulfide for enabling high areal capacity lithiumsulfur all-solid-state batteries is shown. Copper sulfide-carbon (CuSC) and three different copper sulfide-sulfurcarbon (CuSS) composites are investigated as positive electrodes in all-solid-state lithium-sulfur batteries. The composites are prepared via facile and low-cost mechanochemical ball-milling. It is found that the CuS/C ratio greatly influences the redox properties of the CuSC cathode. Scanning electron microscopy, ex-situ X-ray diffraction, and galvanostatic cycling were also conducted to evaluate the CuSS composite electrodes in Li|LiI-Li$_{3}$PS$_{4}$|CuS–S–C solid-state cells. High mass loading cells made using these composite electrodes deliver capacities as high as 1600 mAh g$^{-1}$$_{(CuS+S)}$ and 7 mAh cm$^{-2}$ at 20 °C. The higher density of CuS also leads to larger volumetric capacities, up to 3900 mAh cm$^{-3}$$_{(CuS+S)}$, thus enabling a potential energy density gain up to 15% with respect to a conventional Carbon–Sulfur cathode

Job Burnout, Stress, and Satisfaction among Emergency Nursing Staff after Health System Transformation Plan in Iran

Introduction: Job burnout, stress, and satisfaction are linked to quality of care, patient outcomes and retention of staff. This study was conducted to determine the mentioned issues among emergency nurses.Methods: This cross-sectional study was conducted on all nurses working in the emergency departments of 10 hospitals in Tehran, Iran, in 2017. Standard questionnaires were used for gathering the data of participants regarding job burnout, stress, and satisfaction. Results: 709 (90%) participants returned the completed questionnaires (58.9% female). The mean age of the nurses was 33 (SD = 7) years. The level of job burnout was moderate in 76.1%, low in 22.5%, and high in 1.4% of the nurses. The level of burnout in the married nursing staff was lower than single nurses (3.78 ± 0.98 versus 4.14 ± 0.58, p = 0.049). The level of job satisfaction was moderate in 61.1%, low in 22.2%, and high in 16.7%. There was a significant correlation between age and job satisfaction (p = 0.027, r = 0.3). Job burnout was directly correlated with job stress (p ≤0.001, r = 0.57) and job burnout was negatively correlated with job satisfaction (p = 0.001, r = -0.41). Conclusion: More than 60% of the studied emergency nurses had moderate levels of job burnout, stress, and satisfaction. Job burnout had a direct correlation with job stress and indirect correlation with job satisfaction. Planning to reduce burnout of the emergency nursing staff seems to be necessary

Disclosing the Redox Pathway Behind the Excellent Performance of CuS in Solid‐State Batteries

Copper sulfide has attracted increasing attention as conversion-type cathode material for, especially, solid-state lithium-based batteries. However, the reaction mechanism behind its extraordinary electroactivity is not well understood, and the various explanations given by the scientific community are diverging. Herein, the CuS reaction dynamics are highlighted by examining the occurring redox processes via a cutting-edge methodology combining X-ray absorption fine structure spectroscopy, and chemometrics to overcome X-ray diffraction limitations posed by the poor material\u27s crystallinity. The mathematical approach rules out the formation of intermediates and clarifies the direct conversion of CuS to Cu in a two-electron process during discharge and reversible oxidation upon delithiation. Two distinct voltage regions are identified corresponding to Cu- as well as the S-redox mechanisms occurring in the material

An improved nine‐level switched capacitor‐based inverter with voltage boosting capability and limitation of capacitor current spikes for PV applications

To proceed to a net zero carbon world and to mitigate the environmental challenges associated with it, integration speed of renewable energy sources such as photovoltaic (PV) systems has been increased around the world. Here, an improved switched-capacitor based nine-level inverter is introduced for PV applications. This topology has several benefits such as, voltage boosting feature, using a single DC source, reduction of capacitor charging current spike and extendable input voltage. This inverter produces nine-level output voltage waveform using single power supply. This topology, using identical two capacitors in parallel with a single DC source, can boost the input voltage. In this inverter to limit spike current of capacitor charging mode, an inductor is placed in the charging path of capacitors with a parallel diode. The power losses and overall efficiency analysis of the improved inverter are considered. To verify the accurate performance of inverter under a step change on power flows, simulation results are obtained by MATLAB/Simulink software and presented. To highlight the benefits of the inverter, a comparison of improved topology with most recent topologies is performed. Finally, to verify the feasibility and performance of the improved inverter, experimental results of a 770 W grid-tied prototype are presented

The Effect of Aromatherapy with Lavender on Pain of Needle Insertion and Severity of Restless Legs Syndrome in Hemodialysis Patients; a Systematic Review and Meta-analysis

Introduction: Pain experienced during the insertion of a catheter into the arteriovenous fistula (AVF) and restless legs syndrome (RLS) are prevalent issues among Hemodialysis (HD) patients. The primary objective of this systematic review and meta-analysis was to consolidate the findings from randomized clinical trial (RCT) studies examining the impact of aromatherapy with lavender on the pain associated with AVF catheter insertion and RLS in HD patients. Methods: A systematic search was conducted on PubMed, Web of Science, Scopus, Cochrane, Embase, ClinicalTrials.gov, and Google Scholar search engine from inception to August 1, 2022, using keywords extracted from Medical Subject Headings, such as “Aromatherapy”, “Lavender”, “Arteriovenous fistula”, “Pain”, “Restless legs syndrome”, and “Hemodialysis”. Results: Finally, eleven articles were included in this systematic review and meta-analysis. The results showed that aromatherapy reduced the average pain of catheter insertion in AVF compared to the control group (Standard Mean Difference: -1.60, 95% Confidence Interval: -2.32 to -0.87, Z=4.32, I2:90.3%, P<0.001). Also, aromatherapy massage reduced the average severity of RLS compared to the control group, which was statistically significant (Weighted Mean Difference: -13.21, 95% Confidence Interval: -17.50 to -8.91, Z=6.03, I2:93.0%, P<0.001). Also, the subgroup analysis showed that lavender in the intervention group significantly decreased the pain intensity compared to the "no intervention" group (P<0.001), yet it was not significant compared to the placebo group (P=0.12). Conclusion: In summary, the findings indicate a notable reduction in catheter insertion pain in AVF and relief from RLS among HD patients through the use of lavender essential oil. As a result, future research is encouraged to include a comparison of lavender's effects with those of a placebo group