bluuebunny/crossref_metadata_2025 huggingface dataset:
A Dual-Population-Based NSGA-III for Constrained Many-Objective Optimization
Authors: Geng Huantong , Zhou Zhengli , Shen Junye , Song Feifei
Published: December 2022

The main challenge for constrained many-objective optimization problems (CMaOPs) is how to achieve a balance between feasible and infeasible solutions. Most of the existing constrained many-objective evolutionary algorithms (CMaOEAs) are feasibility-driven, neglecting the maintenance of population convergence and diversity when dealing with conflicting objectives and constraints. This might lead to the population being stuck at some locally optimal or locally feasible regions. To alleviate the above challenges, we proposed a dual-population-based NSGA-III, named DP-NSGA-III, where the two populations exchange information through the offspring. The main population based on the NSGA-III solves CMaOPs and the auxiliary populations with different environment selection ignore the constraints. In addition, we designed an ε-constraint handling method in combination with NSGA-III, aiming to exploit the excellent infeasible solutions in the main population. The proposed DP-NSGA-III is compared with four state-of-the-art CMaOEAs on a series of benchmark problems. The experimental results show that the proposed evolutionary algorithm is highly competitive in solving CMaOPs.
Reflection on Value and Function of Information Technology Curriculum from the Reform of the British ICT Curriculum
Authors: Li Xinlei , Zhang Jinbao , van Braak Johan
Published: December 2022

In the context of social transformation, the needs of society and individuals for information technology are changing, and discussions on the value and function of information technology are getting more and more attention. The purpose of this research is to clarify the value problems of the information technology curriculum and its function for nurturing students in primary and secondary schools. This research adopts content analysis and comparative research methods, which focus on the process, content selection, and implementation status of information and communication technology (ICT) in the Computing curriculum of British primary and secondary schools. This research content is based on an analysis perspective of curriculum value theory from levels of social and human development, and finally formed the analysis framework of value in information technology curriculum standards. The research results analyze reasons for changes in the value orientation and practical performance of the information technology curriculum standards in Britain to help understand trends and challenges of information technology reform in different contexts. Finally, this research finds the effects of content and value changes of curriculum standards on social and student development and puts forward conclusions for the position and value of information technology in the future of learning and teaching in the context of educational informatization.
Experimental Analysis to Detect Corona COVID-19 Virus Symptoms in Male Patients through Breath Pattern Using Machine Learning Algorithms
Authors: Mayet Abdulilah Mohammad , Shukla Neeraj Kumar , Raja M. Ramkumar , Ahmad Ijaz , Aiesh Qaisi Ramy Mohammed , Al-Qahtani Ali Awadh , Taparwal Anita , Tirth Vineet , AL-Dossary Reem
Published: December 2022

In the fourth quarter of the year 2019, the planet became overwhelmed by the pandemic caused by the coronavirus disease (COVID-19). This virus imperiled human life and have affected a considerable percentage of the world population much before its early stage detection mechanisms were discovered and made available at the grassroots level. As there is no specific drug available to treat this infection, the vaccine was intended to serve as the ultimate weapon in the war against this species of coronavirus, but like other viruses, being an RNA virus, this virus also mutates continuously while it passes from one human to the other, making the development of highly potent vaccines even more challenging. This work is being sketched at the juncture when a huge percentage of the human population is already affected by this virus globally. In this work, we are proposing an idea to develop an app to detect coronavirus (COVID-19) symptoms at an early stage by self-diagnosis at home or at the clinical level. An experimental study has been performed on a dummy dataset with 11000 entries of various breadth patterns based on the spirometry analysis, lung volume analysis, and lung capacity analysis of normal male subjects and detailed breath patterns of infected male patients. A logistic regression model is trained after using SMOTE oversampling to balance the data and the predictive accuracy levels of 80%, 78%, and 90%. The results accomplished through this study and experiments may not only aid the clinicians in their medical practice but may also bestow a blue chip to the masterminds engaged in the biomedical research for inventing more evolved, sophisticated, user-friendly, miniaturized, portable, and economical medical app/devices in the future.
Organic Scintillator-Fibre Sensors for Proton Therapy Dosimetry: SCSF-3HF and EJ-260
Authors: Penner Crystal , Usherovich Samuel , Niedermeier Jana , Belanger-Champagne Camille , Trinczek Michael , Paulssen Elisabeth , Hoehr Cornelia
Published: December 2022

In proton therapy, the dose from secondary neutrons to the patient can contribute to side effects and the creation of secondary cancer. A simple and fast detection system to distinguish between dose from protons and neutrons both in pretreatment verification as well as potentially in vivo monitoring is needed to minimize dose from secondary neutrons. Two 3 mm long, 1 mm diameter organic scintillators were tested for candidacy to be used in a proton–neutron discrimination detector. The SCSF-3HF (1500) scintillating fibre (Kuraray Co. Chiyoda-ku, Tokyo, Japan) and EJ-260 plastic scintillator (Eljen Technology, Sweetwater, TX, USA) were irradiated at the TRIUMF Neutron Facility and the Proton Therapy Research Centre. In the proton beam, we compared the raw Bragg peak and spread-out Bragg peak response to the industry standard Markus chamber detector. Both scintillator sensors exhibited quenching at high LET in the Bragg peak, presenting a peak-to-entrance ratio of 2.59 for the EJ-260 and 2.63 for the SCSF-3HF fibre, compared to 3.70 for the Markus chamber. The SCSF-3HF sensor demonstrated 1.3 times the sensitivity to protons and 3 times the sensitivity to neutrons as compared to the EJ-260 sensor. Combined with our equations relating neutron and proton contributions to dose during proton irradiations, and the application of Birks’ quenching correction, these fibres provide valid candidates for inexpensive and replicable proton-neutron discrimination detectors.
Impact of Solar Energy Integration on the Rheological and Chemical Properties of Bitumen
Authors: Tahri Amina , Bouya Mohsine , Ghazouani Mokhtar , Achak Ouafae , Chafik Tarik , Azdi Khalid El , Boughanbour Sanae
Published: December 2022

The use of solar energy to partially satisfy the demand for heat in the bitumen industry constitutes an enormous step towards industrial decarbonization. This paper investigates the effect of thermal fluctuations caused by solar energy usage in bitumen storage in the region of Rabat, Morocco. We studied different temperature ranges and storage periods, covering the most common scenarios in this region. This work inspected the impact of these studied conditions on the performance of 35/50 bitumen. After the simulation of fluctuations through thermal storage, we simulated short-term and long-term aging using RTFO and PAV tests, respectively. In addition to the needle penetration at 25 °C and the determination of softening point tests, we used a dynamic shear rheometer (DSR) and Fourier-transform infrared spectroscopy (FTIR) to assess the rheological and chemical evolutions of the samples. We found that thermal fluctuations enhanced the rheological performance of the binders by improving their rutting and fatigue cracking resistance. We observed that longer storage durations (three months) under thermal fluctuations made bitumen more prone to oxidation in the long term. We conclude that solar energy usage in bitumen storage is not detrimental as long as we avoid long storage periods (more than one month), especially when the maximum storage temperature is higher than 165 °C.
A Review of Electrochemical Reduction of Sodium Metaborate
Authors: Basirun Wan Jefrey , Shah Syed Tawab , Shalauddin Md. , Akhter Shamima , Jamaludin Nazzatush Shimar , Hayyan Adeeb
Published: December 2022

The recycling of sodium borohydride poses a huge challenge to the drive towards a hydrogen economy. Currently, mechano-chemical, thermo-chemical and electrochemical are the only reported methods of recycling sodium metaborate into sodium borohydride. Much attention has been devoted to the mechano-chemical and thermo-chemical methods of reduction, but little focus has been devoted to electrochemical methods. This review describes the electrochemical behaviour of borohydride (BH4−) and metaborate (BO2−) anions in alkaline solutions. The BH4− is stabilized in highly concentrated alkaline solutions, while the electro-oxidation of BH4− is dependent on the type of electrode material. The attempts to electro-reduce the BO2− into BH4− is reviewed and the challenges, suggestions and future outlook of electro-reduction for the recycling of BO2− into BH4− is highlighted.
Comprehensive Study on Reduced DC Source Count: Multilevel Inverters and Its Design Topologies
Authors: Eswar Kommoju Naga Durga Veera Sai , Doss Mohan Arun Noyal , Vishnuram Pradeep , Selim Ali , Bajaj Mohit , Kotb Hossam , Kamel Salah
Published: December 2022

Due to cutting-edge innovations in industry and academia, research is more centered around multilevel inverters (MLIs), which play a significant role in different high/medium voltage and high-power applications when contrasted with traditional inverters. Relative analysis of the reduced DC source count and switch inverter topologies highlight its significant benefits, which include control complexity, switch count, source count, reliability, efficiency, cost, voltage stress, total harmonic distortion (THD), and power quality. When switched-capacitor technology is deployed, it is seen that with the assistance of 14 switches, a 53 level result is accomplished, and the THD is just around 1.41%, which is kept up with as per the IEEE 519-2014 norms. Whenever cascaded MLI topology is employed, the inversion efficiency is more prominent, and is about 99.06%. Hence, this review focuses on a few of the late-evolved MLIs utilized, and the benefits and drawbacks for different topologies are examined. To assist with current modern research in this field and the decision of the proper inverter for various applications, a novel topology of an MLI can be planned later on. Different setups of MLIs have been exhaustively covered and reviewed.
Effect of Fertilization with Meat and Bone Meal on the Production of Biofuel Obtained from Corn Grain
Authors: Stępień Arkadiusz , Rejmer Wojciech
Published: December 2022

The large volumes of meat and bone meal (MBM) being produced are leading to an increased demand for research into innovative methods of utilizing MBM and obtaining further benefits. The object of this study is to analyze the efficiency of bioethanol and biodiesel production obtained from corn grain fertilized with meat and bone meal produced from animal waste. For the realization of this study, a four-year field experiment was carried out with grain corn fertilized with different doses of meat and bone meal in comparison to fertilization with mineral fertilizers and no fertilization. Fertilization with meat and bone meal should be considered not only for its direct effect but also for the after-effect. The effect of meat and bone meals on obtaining a grain yield higher than that obtained on objects without fertilization and those fertilized with mineral fertilizers was noticeable after applying higher doses from the third year of the study. Fertilization with meat and bone meals did not significantly affect the average fat content of grain, and it only slightly affected the starch content. The positive effect of meat and bone meals on the yield of bioethanol from grain extracted from one hectare was responsible for their yield-forming effect. The differences obtained between years and between fertilizer variants in the yields of ethyl biodiesel and methyl biodiesel per one hectare were mainly related to grain yields, rather than the obtained volume per 1 kg from grain.
Intelligent SOX Estimation for Automotive Battery Management Systems: State-of-the-Art Deep Learning Approaches, Open Issues, and Future Research Opportunities
Authors: Hossain Lipu Molla , Karim Tahia , Ansari Shaheer , Miah Md. , Rahman Md. , Meraj Sheikh , Elavarasan Rajvikram , Vijayaraghavan Raghavendra
Published: December 2022

Real-time battery SOX estimation including the state of charge (SOC), state of energy (SOE), and state of health (SOH) is the crucial evaluation indicator to assess the performance of automotive battery management systems (BMSs). Recently, intelligent models in terms of deep learning (DL) have received massive attention in electric vehicle (EV) BMS applications due to their improved generalization performance and strong computation capability to work under different conditions. However, estimation of accurate and robust SOC, SOH, and SOE in real-time is challenging since they are internal battery parameters and depend on the battery’s materials, chemical reactions, and aging as well as environmental temperature settings. Therefore, the goal of this review is to present a comprehensive explanation of various DL approaches for battery SOX estimation, highlighting features, configurations, datasets, battery chemistries, targets, results, and contributions. Various DL methods are critically discussed, outlining advantages, disadvantages, and research gaps. In addition, various open challenges, issues, and concerns are investigated to identify existing concerns, limitations, and challenges. Finally, future suggestions and guidelines are delivered toward accurate and robust SOX estimation for sustainable operation and management in EV operation.
Valorization of Used Lubricating Oils as a Possible Base Oil Source to Avoid Groundwater Pollution in the South of Algeria
Authors: BENDJERAD Abdelmadjid Mahfoudh , CHEIKH Nawel , BENMEHDI Houcine , MONTRELAY Nicolas , HOUESSOU Koffi Justin , PIERENS Xavier , BEN-HABIB Karim , GOULLIEUX Adeline , DHEILLY Rose Marie
Published: December 2022

The lubricating oil industry is widespread in the world, but getting rid of the used oils has become an environmental concern. Lubricating oils are used in industries and cars but potentially contaminate groundwater after use. This research uses montmorillonite clay to refine old oil treated with acetic acid. Compared to more conventional procedures, the suggested strategy for treating waste oil is more cost-effective due to the relatively inexpensive cost of the acid and the modest process conditions. Water content, sediment content, density, flash and fire points, viscosity, viscosity index, total acid and base number, pour points, and refractive index were among the physicochemical parameters of the treated oil that were examined as a result of this treatment. We analyzed the oils using Fourier transform infrared spectroscopy (FTIR) and atomic absorption spectrometry (AAS). New oil (10w 40), old oil, oil treated with acetic acid, and montmorillonite clay were all put through their paces in a battery of tests. The therapy’s physical and chemical alterations were examined across all fields. The findings demonstrated the efficiency of montmorillonite clay due to the strength of the acid to separate the sludge and the lack of compounds hazardous to the environment. The process described here enables recycled oil to be reclaimed as base oil.
Information Analysis on Foreign Institution for International R&D Collaboration Using Natural Language Processing
Authors: Jung Jihoo , Lee Jehyun , Choi Sangjin , Baek Woonho
Published: December 2022

The number of international collaborations in research and development (R&D) has been increasing in the energy sector to solve global environmental problems—such as climate change and the energy crisis—and to reduce the time, cost, and risk of failure. Successful international project planning requires the analysis of research fields and the technology expertise of cooperative partner institutions or countries, but this takes time and resources. In this study, we developed a method to analyze the information on research organizations and topics, taking advantage of data analysis as well as deep learning natural language processing (NLP) models. A method to evaluate the relative superiority of efficient international collaboration was suggested, assuming international collaboration of the National Renewable Energy Laboratory (NREL) and the Korea Institute of Energy Research (KIER). Additionally, a workflow of an automated executive summary and a translation of tens of web-posted articles is also suggested for a quick glance. The valuation of the suggested methodology is estimated as much as the annual salary of an experienced employee.
Merging Climate Action with Energy Security through CCS—A Multi-Disciplinary Framework for Assessment
Authors: Gładysz Paweł , Strojny Magdalena , Bartela Łukasz , Hacaga Maciej , Froehlich Thomas
Published: December 2022

Combining biomass-fired power generation with CO2 capture and storage leads to so-called negative CO2 emissions. Negative CO2 emissions can already be obtained when coal is co-fired with biomass in a power plant with CCS technology. The need for bioenergy with CO2 capture and storage has been identified as one of the key technologies to keep global warming below 2 °C, as this is one of the large-scale technologies that can remove CO2 from the atmosphere. According to the definition of bioenergy with CO2 capture and storage, capturing and storing the CO2 originating from biomass, along with the biomass binding with carbon from the atmosphere as it grows, will result in net removal of CO2 from the atmosphere. Another technology option for CO2 removal from the atmosphere is direct air capture. The idea of a net carbon balance for different systems (including bioenergy with CO2 capture and storage, and direct air capture) has been presented in the literature. This paper gives a background on carbon dioxide removal solutions—with a focus on ecology, economy, and policy-relevant distinctions in technology. As presented in this paper, the bioenergy with CO2 capture and storage is superior to direct air capture for countries like Poland in terms of ecological impact. This is mainly due to the electricity generation mix structure (highly dependent on fossil fuels), which shifts the CO2 emissions to upstream processes, and relatively the low environmental burden for biomass acquisition. Nevertheless, the depletion of non-renewable natural resources for newly built bioenergy power plant with CO2 capture and storage, and direct air capture with surplus wind energy, has a similar impact below 0.5 GJ3x/t of negative CO2 emissions. When the economic factors are a concern, the use of bioenergy with CO2 capture and storage provides an economic justification at current CO2 emission allowance prices of around 90 EUR/t CO2. Conversely, for direct air capture to be viable, the cost would need to be from 3 to 4.5 times higher.
Experiments on Water-Gas Flow Characteristics under Reservoir Condition in a Sandstone Gas Reservoir
Authors: Li Yilong , Yang Hao , Li Xiaoping , Kui Mingqing , Zhang Jiqiang
Published: December 2022

For gas reservoirs that contain water, investigating characteristics of water–gas seepage is crucial to the formulation of gas field development plans and predicting the production capacity and water breakthrough of gas wells. For the purposes of such an investigation, the process of water invasion into a water-containing gas reservoir was studied based on four sandstone samples whose physical properties differed quite vastly (permeability: 0.112–192.251 mD; porosity: 8.33–20.60%). Gas–water relative permeability experiments were conducted on the gas-driven water in the reservoir conditions (temperature: 135 °C; pressure: 75 MPa). Starting with the sandstone samples’ microstructural characteristics, particular attention was paid to the impacts of throat radius and clay content on the water–gas seepage characteristics. It was found that the basic physical properties, microscopic characteristics, and mineral composition of the sandstone samples all affected the water–gas seepage characteristics. The larger the pore-throat radius, the stronger the ability of sandstone samples to allow fluid through under the same water saturation and the greater the relative permeability of gas and water phases. Furthermore, the wider the throat radius and the lower the clay content, the greater the gas–water relative permeability. Isotonic water saturation and irreducible water saturation were found to be negatively to throat radius and positively with clay content. Furthermore, When sandstone samples have similar clay content, the average throat radius is four times larger, its irreducible water saturation is decreased by 1.63%, its residual gas saturation is decreased by 1.00%, and the gas permeability under irreducible water saturation increases by more than 400 times. Water intrusion showed a more significant impact on the gas–water flow characteristics of the low-permeability sandstone samples, and it severely restricted the flow capacity of the gas phase.
The Effect of Electrospinning Parameters on Piezoelectric PVDF-TrFE Nanofibers: Experimental and Simulation Study
Authors: Pourbafrani Mehdi , Azimi Sara , Yaghoobi Nia Narges , Zendehdel Mahmoud , Abolhasani Mohammad Mahdi
Published: December 2022

Polyvinylidene fluoride and its copolymers can be used as active materials for energy harvesting and environmental sensing. Energy harvesting is one of the most recent research techniques for producing stable electrical energy from mechanical sources. Polyvinylidene fluoride–trifluoroethylene (PVDF-TrFE) is applicable for sensors and self-powered devices such as medical implants and wearable electronic devices. The preparation of electrospun P(VDF-TrFE) nanofibers is of great interest for the fabrication of sensors and self-powered devices, nanogenerators, and sensors. In this regard, it is necessary to investigate the effects of various parameters on the morphology and piezoelectric output voltage of such nanofibers. In this study, we have examined the effect of concentration and feed rate on the nanofiber diameter. It has been found that by increasing the concentration and feed rate of the polymer solution, the diameter of the nanofibers increases. The experimental results and the finite element method (FEM) simulation have also shown consistency; when the nanofiber diameter increases, the output voltage of the nanofibers decreases. This behavior can be related to the strain reduction in the deformed nanofibers.
Numerical Investigation of the Initial Charging Process of the Liquid Hydrogen Tank for Vehicles
Authors: Kang Daehoon , Yun Sungho , Kim Bo-kyong , Kim Jaewon , Kim Gildong , Lee Hyunbae , Choi Sangyeol
Published: December 2022

Liquid hydrogen has been studied for use in vehicles. However, during the charging process, liquid hydrogen is lost as gas. Therefore, it is necessary to estimate and reduce this loss and simulate the charging process. In this study, the initial charging process of a vehicle liquid hydrogen tank under room temperature and atmospheric pressure conditions was numerically investigated. A transient thermal-fluid simulation with a phase-change model was performed to analyze variations in the volume, pressure, mass flow rate, and temperature. The results showed that the process could be divided into three stages. In the first stage, liquid hydrogen was actively vaporized at the inner wall surface of the storage tank. The pressure increased rapidly, and liquid droplets were discharged into the vent pipe during the second stage. In the third stage, the mass flow rates of liquid and hydrogen gas at the outlet showed significant fluctuations, owing to complex momentum generated by the evaporation and charging flow. The temperatures of the inner and outer walls, and insulation layer, decreased significantly slower than that of the gas region because of its high heat capacity and insulation effect. The optimal structure should be further studied because the vortex, stagnation, and non-uniform cooling of the wall occurred near the inlet and outlet pipes.
Novel Mathematical Design of Triple-Tuned Filters for Harmonics Distortion Mitigation
Authors: Maher Mohamed , Abdel Aleem Shady H. E. , Ibrahim Ahmed M. , El-Shahat Adel
Published: December 2022

The design of AC filters must meet the criteria of harmonic distortion mitigation and reactive power support in various operating modes. The stringent reactive power-sharing requirements currently lead to sophisticated filter schemes with high component ratings. In this regard, triple-tuned filters (TTFs) have good potential in harmonic mitigation of a broad range of harmonics. In the literature, the TTF design has been presented using a parametric method, assuming that the TTF is equivalent to a three-arm single-tuned filter (TASTF). However, no direct methods of designing it or finding its optimal parameters have been provided. This paper presents novel mathematical designs of TTFs. Three different design methods are considered—the direct triple-tuned filter (DTTF) design method, as a TASTF, and a method based on the equivalence between the two design methods called the equivalence hypothesis method to design the triple-tuned filter (EHF). The parameters of the three proposed design methods are optimized based on the minimization of a proposed multi-objective function using a recent metaheuristic algorithm called artificial rabbits optimization (ARO) to mitigate harmonics, improve power quality, and minimize power losses in an exemplary system presented in IEEE STD-519. Further, the system’s performance has been compared to the system optimized by the ant lion optimizer (ALO) and whale optimization algorithm (WOA) to validate the effectiveness of the proposed design. Simulation results emphasized harmonics mitigation in the system, the system losses reduction, and power quality improvement with lower reactive power filter ratings than conventional single and double-tuned filters.
Prospective of Response Surface Methodology as an Optimization Tool for Biomass Gasification Process
Authors: Asaad Sara Maen , Inayat Abrar , Rocha-Meneses Lisandra , Jamil Farrukh , Ghenai Chaouki , Shanableh Abdallah
Published: December 2022

The worldwide population growth and the technological advancements reported in the past few years have led to an increase in the production and consumption of energy. This has increased greenhouse gas (GHG) emissions, the primary driver of climate change. As a result, great attention has been paid to sustainable and green energy sources that can replace or reduce reliance on non-sustainable energy sources. Among the different types of renewable energy sources currently available, bioenergy has been reported as an attractive resource mainly due to its low cost and great availability. Bioenergy can be produced from different biomass sources and converted into biofuels or value-added products through thermochemical, biochemical, and chemical processes. Gasification is a thermochemical process commonly used for bioenergy production, and it is particularly attractive mainly due to its high efficiency. However, its performance is influenced by parameters such as type of feedstock, size of biomass particle, feed rate, type of reactor, temperature, pressure, equivalence ratio, steam to biomass ratio, gasification agent, catalyst, and residence time. In this paper, the influence of different performance parameters in the gasification process is analyzed, and optimization and modelling techniques are proposed as a strategy for product yield enhancement.
A Generalized Fault Tolerant Control Based on Back EMF Feedforward Compensation: Derivation and Application on Induction Motors Drives
Authors: Tousizadeh Mahdi , Yazdani Amirmehdi , Che Hang Seng , Wang Hai , Mahmoudi Amin , Rahim Nasrudin Abd
Published: December 2022

In this paper, a fault-tolerant three-phase induction drive based on field-oriented control is studied, and an analytical approach is proposed to elucidate the limitations of FOC in flux-torque regulation from the controller perspective. With an open-phase fault, the disturbance terms appear in the controller reference frame and degrade the controller performance when operating in a d-q plane with DC quantities. In addition, the hardware reconfiguration, which is essential to operate faulted three-phase drives, causes substantial change in the way the control parameters vd, vq are reflected onto the machine terminals. An accurate understanding of the feedforward term, by considering the open-phase fault and the hardware modifications, is provided to re-enable the FOC in presence of an open-phase fault. Furthermore, the concept of feedforward term derivation is generically extended to cover multiphase induction drives encountering an open-phase fault whereby no hardware reconfiguration is intended. The proposed method is explained based on a symmetrical six-phase induction and can be extended to drives with a higher number of phases. The effectiveness of the proposed derivation method, which is required to form a feedforward fault-tolerant controller, is verified and compared through the simulation and experiment, ensuring smooth operation in postfault mode.
Electrical Phenomena on Fully Airborne Vertical Electric Antennas in Extreme Weather Conditions
Authors: Miś Tomasz Aleksander , Modelski Józef
Published: December 2022

This is a conference extension of the paper ‘Investigation on the mature storm cloud’s electric field using long airborne antennas’. The use of vertical antennas (including the VEDs—Vertical Electric Dipoles), lifted up by aerostats to high altitudes without being anchored to the ground, presents numerous advantages in comparison with large terrestrial VLF (Very Low Frequency) antenna structures. A slow-moving floating-earth conductor—a vertical wire antenna—is subjected to intense electrification mechanisms in the atmosphere and inside the cloud layers, producing additional risks for the transmitter and the flight train itself. The electrical potential achieved in this process is, therefore, compared with the flashover voltages over the antenna’s upper fixing point, defining the voltage margins at which the VLF transmitter is able to operate. The electrification processes are also compared to the model based on experimental data on the occurrence of corona discharges over a long, vertical wire traversing a storm cloud layer. The external electric field strength (around the antenna wire) is calculated and compared with older experimental data for storm clouds for various locations, showing the correctness of the proposed analytical electrification model, and, therefore, expanding it with the loss of the electric charge via corona.
Natural Esters for Green Transformers: Challenges and Keys for Improved Serviceability
Authors: Oparanti Samson Okikiola , Rao Ungarala Mohan , Fofana Issouf
Published: December 2022

The service of mineral insulating oils for power transformer insulation and cooling aspects cannot be disavowed. However, the continued use of mineral oils is questionable due to environmental unfriendliness and the divestment from fossil fuels. This has provoked the quest for green alternative insulating liquids for high-voltage insulation. Natural esters are among the remaining alternatives that are renewable and environmentally friendly. Regardless of their environmental and technical merits, natural esters have some limitations that are slowing down their total acceptance by transformer owners and utilities. Critical limitations and concerns include esters’ pour point, viscosity, oxidative stability, and ionization resistance. In this work, the state of the art of “natural esters for transformers” is explored with the aim of potential improvements. The sections of the article are geared towards technical viewpoints on improving the overall workability and serviceability of natural esters in high-voltage applications. A comprehensive review of the existing literature is achieved, based on performance improvements of the natural ester using “additives” and “chemical modification”. The authors hope that this report may be helpful to transformer owners as well as influence the progression of natural esters for power transformer applications.
Reliability Estimation for Dependent Left-Truncated and Right-Censored Competing Risks Data with Illustrations
Authors: Zuo Zhiyuan , Wang Liang , Lio Yuhlong
Published: December 2022

In this paper, a competing risks model with dependent causes of failure is considered under left-truncated and right-censoring scenario. When the dependent failure causes follow a Marshall–Olkin bivariate exponential distribution, estimation of model parameters and reliability indices are proposed from classic and Bayesian approaches, respectively. Maximum likelihood estimators and approximate confidence intervals are constructed, and conventional Bayesian point and interval estimations are discussed as well. In addition, E-Bayesian estimators are proposed and their asymptotic behaviors have been investigated. Further, another objective-Bayesian analysis is also proposed when a noninformative probability matching prior is used. Finally, extensive simulation studies are carried out to investigate the performance of different methods. Two real data examples are presented to illustrate the applicability.
Induction Generator with Direct Control and a Limited Number of Measurements on the Side of the Converter Connected to the Power Grid
Authors: Kasprowicz Andrzej Bogdan , Husev Oleksandr , Strzelecki Ryszard
Published: December 2022

The article presents an induction generator connected to the power grid using the AC/DC/AC converter and LCL coupling filter. Three-level inverters were used in the converter, both from the generator side and the power grid side. The algorithm realizing Pulse Width Modulation (PWM) in inverters has been simplified to the maximum. Control of the induction generator was based on the Direct Field-Oriented Control (DFOC) method. At the same time, voltage control has been used for this solution. The MPPT algorithm has been extended to include the variable pitch range of wind turbine blades. The active voltage balancing circuit has been used in the inverter DC voltage circuit. In the control system of the grid converter with an LCL filter, the number of measurements was limited to the measurement of power grid currents and voltages. Synchronization of control from the power grid side is ensured by the use of a PLL loop with the system of preliminary suppression of undesired harmonics.
Power Grid Infrastructural Resilience against Extreme Events
Authors: Daeli Ahmed , Mohagheghi Salman
Published: December 2022

Extreme weather events are one of the main causes of large-scale power outages in distribution systems. The changing climate has led to an increase in the frequency and severity of these events, which, if not mitigated, are expected to lead to more instances of widespread outages and the severe societal and economic damages that ensue. Protecting the power grid against such events, which are high impact yet low frequency, requires a paradigm shift in grid design practices. In recent years, many researchers have focused on the resilience of the power grid against extreme weather events by proposing various grid hardening and/or redundancy solutions. The goal of this paper is to provide a survey of the literature related to the infrastructural resilience of the power grid against extreme events. Currently, no standard definitions or metrics exist for power grid resilience, and researchers adopt various models for quantifying and assessing it. Hence, a review of the most commonly used definitions and metrics for resilience is provided first, with a discussion of their advantages and disadvantages. Next, the paper presents an extensive and critical review of the solution methodologies proposed in the literature for improving the infrastructural resilience of the power grid. The shortcomings of the current solution methods and gaps in research are identified, followed by a discussion of the future directions in research.
A Review on Heat Transfer Characteristics and Enhanced Heat Transfer Technology for Helium–Xenon Gas Mixtures
Authors: Zhao Fulong , Mei Yiguo , Liang Tiebo , Wang Bin , Jing Hao , Chen Weixiong
Published: December 2022

As one of the most promising working substances for space nuclear power sources, research on the heat transfer characteristics of helium–xenon gas mixtures has become the key issue in focus. In this paper, through an extensive literature research, the current research results are classified and organized. The results show that there are semi-empirical formulas for physical property parameters with high prediction accuracy, and there are also Nusselt correlations with small errors. However, both lack the support of experimental data. There is no systematic research on enhanced heat transfer technologies, and the conclusions of the existing studies are not significant, so they can only make limited reference contributions to the future study of enhanced heat transfer technologies. More flow and heat transfer experiments on helium–xenon mixtures are urgently needed, through detailed analysis of the heat transfer performance of helium–xenon flow, identifying the key factors affecting the heat transfer thermal resistance, and corresponding heat transfer enhancement measures to form an optimized design method applicable to helium–xenon heat exchangers. In this way, an enhanced heat transfer theory of helium–xenon heat exchangers can be developed.
Multi-Objective Energy Management Strategy for Hybrid Electric Vehicles Based on TD3 with Non-Parametric Reward Function
Authors: Yan Fuwu , Wang Jinhai , Du Changqing , Hua Min
Published: December 2022

The energy management system (EMS) of hybridization and electrification plays a pivotal role in improving the stability and cost-effectiveness of future vehicles. Existing efforts mainly concentrate on specific optimization targets, like fuel consumption, without sufficiently taking into account the degradation of on-board power sources. In this context, a novel multi-objective energy management strategy based on deep reinforcement learning is proposed for a hybrid electric vehicle (HEV), explicitly conscious of lithium-ion battery (LIB) wear. To be specific, this paper mainly contributes to three points. Firstly, a non-parametric reward function is introduced, for the first time, into the twin-delayed deep deterministic policy gradient (TD3) strategy, to facilitate the optimality and adaptability of the proposed energy management strategy and to mitigate the effort of parameter tuning. Then, to cope with the problem of state redundancy, state space refinement techniques are included in the proposed strategy. Finally, battery health is incorporated into this multi-objective energy management strategy. The efficacy of this framework is validated, in terms of training efficiency, optimality and adaptability, under various standard driving tests.
Microbial Granule Technology—Prospects for Wastewater Treatment and Energy Production
Authors: Kazimierowicz Joanna , Dębowski Marcin , Zieliński Marcin
Published: December 2022

Recent years have brought significant evolution and changes in wastewater treatment systems. New solutions are sought to improve treatment efficiency, reduce investment/operational costs, and comply with the principles of circular economy and zero waste. Microbial granules can serve as an alternative to conventional technologies. Indeed, there has been fast-growing interest in methods harnessing aerobic (AGS) and anaerobic (AnGS) granular sludge as well as microbial-bacterial granules (MBGS), as evidenced by the number of studies on the subject and commercial installations developed. The present paper identifies the strengths and weaknesses of wastewater treatment systems based on granular sludge (GS) and their potential for energy production, with a particular focus on establishing the R&D activities required for further advance of these technologies. In particular, the impact of granules on bioenergy conversion, including bio-oil recovery efficiency and biomethane/biohydrogen yields, and bioelectrochemical systems must be assessed and optimized.
Prediction of NOx Emissions from a Coal-Fired Boiler Based on Convolutional Neural Networks with a Channel Attention Mechanism
Authors: Li Nan , Lv You , Hu Yong
Published: December 2022

This paper presents a small and efficient model for predicting NOx emissions from coal-fired boilers. The raw data collected are processed by the min–max scale method and converted into a multivariate time series. The overall model’s architecture is mainly based on building blocks consisting of separable convolutional neural networks and efficient channel attention (ECA) modules. The experimental results show that the model can learn good representations from sufficient data covering different operation conditions. These results also suggest that ECA modules can improve the model’s performance. The comparative study shows our model’s strong performance compared to other NOx prediction models. Then, we demonstrate the effectiveness of the model proposed in this paper in terms of predicting NOx emissions.
Spatiotemporal Evolution and Fluctuation Characteristics of a Centrifugal Compressor under Near-Stall Conditions and High Mass-Flow Rate
Authors: Xiao Kang , Wang Zhengdao , Yang Hui , Wei Yikun
Published: December 2022

Spatiotemporal evolution and fluctuation characteristics of a centrifugal compressor are investigated by numerical simulation under near-stall conditions and with a high mass-flow rate. The large-eddy simulation (LES) for unsteady computations is implemented in the numerical simulation of unsteady flow. The internal flow physical mechanism of the centrifugal compressor is presented at a high mass-flow rate (1.1 Qn) and low mass-flow rate (0.8 Qn, near-stall). The spatiotemporal evolution of the velocity and streamline for the internal flow of the centrifugal compressor demonstrates that a lot of large-scale eddies near the tongue are transformed into small-scale ones at high mass-flow rates. High mass-flow rate resulted in excessive fluid velocity in the impeller. A large amount of impact loss massive backflow appears near the tip clearance, and boundary layer separation of the suction surface emerges firstly and at a low mass-flow rate. Considerable flow loss occurs in the centrifugal compressor at the two non-designed operating flow rates. Several pressure and velocity fluctuations in the key position of the compressor are presented by the two deviations from design conditions. The analysis of the fast Fourier transform (FFT) and amplitude spectrum show that the starting point of flow instability in the impeller is different for the two deviations from design-condition flow rates. Understanding the spatiotemporal evolution and spatiotemporal characteristics of pressure and velocity fluctuations can provide insight into the unsteady internal flow of centrifugal compressors at high mass-flow rates (1.1 Qn) and near-stall conditions (0.8 Qn).
Active Air-Source Heat Storage and Release System for Solar Greenhouses: Design and Performance
Authors: Xiang Yingfeng , Shi Mingwen , Li Chuanzhen , Zhu Chao , Cao Yifan , Chen Yangda , Wu Weijun , Li Yapeng , Guo Xuxin , Sun Xianpeng
Published: December 2022

The temperature difference between day and night in a solar greenhouse is large. Heat in a greenhouse is typically in excess during the day while the temperature is low and the humidity is high at night. This study designs and tests an active heat storage and release air-source heat-pump system with a thermally insulated water tank as the energy storage body. By comparing air temperature and humidity in a test greenhouse with a control greenhouse in typical weather conditions, the power consumption and performance of the system are evaluated. The results show that compared with the control greenhouse, the average daytime temperature of the test greenhouse is lowered by about 3 °C during the operation of the system in typical weather conditions. At night, the average temperature is increased by about 4 °C, and the relative humidity is decreased by about 20%. When optimized, the maximum coefficient of performance (COP) of the system can reach 4.32 in heat storage mode. The nighttime heat release from the energy storage tank accounts for 26.9% to 51.2% of the nighttime energy consumption, and the energy utilization efficiency is 59.6% to 497.0%. This study provides a new way to control environmental parameters in solar greenhouses.
Handling Computation Hardness and Time Complexity Issue of Battery Energy Storage Scheduling in Microgrids by Deep Reinforcement Learning
Authors: Sun Zeyue , Eskandari Mohsen , Zheng Chaoran , Li Ming
Published: December 2022

With the development of microgrids (MGs), an energy management system (EMS) is required to ensure the stable and economically efficient operation of the MG system. In this paper, an intelligent EMS is proposed by exploiting the deep reinforcement learning (DRL) technique. DRL is employed as the effective method for handling the computation hardness of optimal scheduling of the charge/discharge of battery energy storage in the MG EMS. Since the optimal decision for charge/discharge of the battery depends on its state of charge given from the consecutive time steps, it demands a full-time horizon scheduling to obtain the optimum solution. This, however, increases the time complexity of the EMS and turns it into an NP-hard problem. By considering the energy storage system’s charging/discharging power as the control variable, the DRL agent is trained to investigate the best energy storage control method for both deterministic and stochastic weather scenarios. The efficiency of the strategy suggested in this study in minimizing the cost of purchasing energy is also shown from a quantitative perspective through programming verification and comparison with the results of mixed integer programming and the heuristic genetic algorithm (GA).
Review on Solar Photovoltaic-Powered Pumping Systems
Authors: Gevorkov Levon , Domínguez-García José Luis , Romero Lluis Trilla
Published: December 2022

Water and energy are becoming more and more important in agriculture, urban areas and for the growing population worldwide, particularly in developing countries. To provide access to water it is necessary to use appropriate pumping systems and supply them with enough energy for operation. Pumps powered by solar photovoltaic energy are complex electromechanical systems that include hydraulic equipment, electrical machines, sensors, power converters, and control units. Therefore, solar photovoltaic pumping systems are associated with various fields of science and engineering. In remote, less-populated areas without electricity, where it is either challenging to connect to the grid or it is not possible, solar photovoltaic water pumping systems can play a significant role. To see whether solar photovoltaic pumping systems may be a practical, viable, and affordable method of pumping water it is necessary to study different aspects of their operation. The goal of this current article is to evaluate and outline recent research and advancement in the field of solar photovoltaic pumping systems. The major focus is on the standalone photovoltaic pumping system’s components, factors that affect system efficiency, performance evaluation, system optimization, and the potential for integration with modern control techniques. The main objective of this article is to give a broader overview of solar photovoltaic technologies for researchers, engineers, and decision-makers.