bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Mean-Field Theory of Ionic Solutions: A Poisson-Nernst-Planck-Bikerman Model
Authors: Liu Jinn-Liang , Eisenberg Bob
Published: May 2020

We have developed a molecular mean-field theory—fourth-order Poisson–Nernst–Planck–Bikerman theory—for modeling ionic and water flows in biological ion channels by treating ions and water molecules of any volume and shape with interstitial voids, polarization of water, and ion-ion and ion-water correlations. The theory can also be used to study thermodynamic and electrokinetic properties of electrolyte solutions in batteries, fuel cells, nanopores, porous media including cement, geothermal brines, the oceanic system, etc. The theory can compute electric and steric energies from all atoms in a protein and all ions and water molecules in a channel pore while keeping electrolyte solutions in the extra- and intracellular baths as a continuum dielectric medium with complex properties that mimic experimental data. The theory has been verified with experiments and molecular dynamics data from the gramicidin A channel, L-type calcium channel, potassium channel, and sodium/calcium exchanger with real structures from the Protein Data Bank. It was also verified with the experimental or Monte Carlo data of electric double-layer differential capacitance and ion activities in aqueous electrolyte solutions. We give an in-depth review of the literature about the most novel properties of the theory, namely Fermi distributions of water and ions as classical particles with excluded volumes and dynamic correlations that depend on salt concentration, composition, temperature, pressure, far-field boundary conditions etc. in a complex and complicated way as reported in a wide range of experiments. The dynamic correlations are self-consistent output functions from a fourth-order differential operator that describes ion-ion and ion-water correlations, the dielectric response (permittivity) of ionic solutions, and the polarization of water molecules with a single correlation length parameter.
Re-Thinking the World with Neutral Monism:Removing the Boundaries Between Mind, Matter, and Spacetime
Authors: Silberstein Michael , Stuckey William
Published: May 2020

Herein we are not interested in merely using dynamical systems theory, graph theory, information theory, etc., to model the relationship between brain dynamics and networks, and various states and degrees of conscious processes. We are interested in the question of how phenomenal conscious experience and fundamental physics are most deeply related. Any attempt to mathematically and formally model conscious experience and its relationship to physics must begin with some metaphysical assumption in mind about the nature of conscious experience, the nature of matter and the nature of the relationship between them. These days the most prominent metaphysical fixed points are strong emergence or some variant of panpsychism. In this paper we will detail another distinct metaphysical starting point known as neutral monism. In particular, we will focus on a variant of the neutral monism of William James and Bertrand Russell. Rather than starting with physics as fundamental, as both strong emergence and panpsychism do in their own way, our goal is to suggest how one might derive fundamental physics from neutral monism. Thus, starting with two axioms grounded in our characterization of neutral monism, we will sketch out a derivation of and explanation for some key features of relativity and quantum mechanics that suggest a unity between those two theories that is generally unappreciated. Our mode of explanation throughout will be of the principle as opposed to constructive variety in something like Einstein’s sense of those terms. We will argue throughout that a bias towards property dualism and a bias toward reductive dynamical and constructive explanation lead to the hard problem and the explanatory gap in consciousness studies, and lead to serious unresolved problems in fundamental physics, such as the measurement problem and the mystery of entanglement in quantum mechanics and lack of progress in producing an empirically well-grounded theory of quantum gravity. We hope to show that given our take on neutral monism and all that follows from it, the aforementioned problems can be satisfactorily resolved leaving us with a far more intuitive and commonsense model of the relationship between conscious experience and physics.
Forecast Accuracy Matters for Hurricane Damage
Authors: Martinez Andrew B.
Published: May 2020

I analyze damage from hurricane strikes on the United States since 1955. Using machine learning methods to select the most important drivers for damage, I show that large errors in a hurricane’s predicted landfall location result in higher damage. This relationship holds across a wide range of model specifications and when controlling for ex-ante uncertainty and potential endogeneity. Using a counterfactual exercise I find that the cumulative reduction in damage from forecast improvements since 1970 is about $82 billion, which exceeds the U.S. government’s spending on the forecasts and private willingness to pay for them.
The Growth of Private Sector and Financial Development in Saudi Arabia
Authors: Haque Mohammad Imdadul
Published: May 2020

In an attempt to diversify itself away from the dominance of oil on its economy, Saudi Arabia needs to emphasize on the growth of its private sector. Currently, the private sector’s contribution to economic growth is meager as the oil sector dominates the economy. This study attempts to assess the role of financial development towards the growth of the private sector. Assessing this relationship is important, as it is quite probable that the dominant oil sector attracts the financial resources, affecting the private sector adversely. Johansen’s method of cointegration is applied on the data for the period 1985–2018. The private sector’s gross domestic product has a negative relation with the supply of money, positive relation with bank credit to private sector, and no significant relationship with share market capitalization, as shown by the results of the study. In addition, the private sector’s growth has a positive and significant relationship with government expenditure, investment, and trade openness. Hence, the study recommends further strengthening of financial sector services. Besides the current trend on government expenditure, investment and trade openness should continue to enable the private sector to contribute significantly to the economic growth of the country. A previous study on the private sector’s growth and financial variables is exclusively missing, and makes this study unique.
Tales from within: Gifted Students’ Lived Experiences with Teaching Practices in Regular Classrooms
Authors: Gomez-Arizaga Maria P. , Valdivia-Lefort Marieta , Castillo-Hermosilla Hernan , Hébert Thomas P. , Conejeros-Solar Maria Leonor
Published: May 2020

Gifted students in regular classrooms have fewer opportunities to develop activities that are based on their characteristics as learners and address their needs; however, many of them spend most of their school time in these classrooms. The results presented here were part of a 2-year qualitative project that analyzed 12 Chilean gifted students’ lived experiences in regular classrooms by exploring the factors that foster and hinder their learning through the use of photos, focus groups, and interviews. The results showed students’ discontent with the national curriculum and teaching practices related to rigidity, lack of meaning, and unchallenging assessments. Nevertheless, positive experiences were reported related to teaching strategies, especially when they add novelty and move away from traditional approaches. Waiting experiences were common, but were often seen by students as opportunities for creative production. Methods for engaging gifted students in their learning are highlighted.
Flow-Shop Predictive Modeling for Multi-Automated Guided Vehicles Scheduling in Smart Spinning Cyber–Physical Production Systems
Authors: Farooq Basit , Bao Jinsong , Ma Qingwen
Published: May 2020

Pointed at a problem that leads to the high complexity of the production management tasks in the multi-stage spinning industry, mixed flow batch production is often the case in response to a customer’s personalized demands. Manual handling cans have a large number of tasks, and there is a long turnover period in their semi-finished products. A novel heuristic research was conducted that considered mixed-flow shop scheduling problems with automated guided vehicle (AGV) distribution and path planning to prevent conflict and deadlock by optimizing distribution efficiency and improving the automation degree of can distribution in a draw-out workshop. In this paper, a cross-region shared resource pool and an inter-regional independent resource pool, two AGV predictive scheduling strategies are established for the ring-spinning combing process. Besides completion time, AGV utilization rate and unit AGV time also analyzed with the bottleneck process of the production line. The results of the optimal computational experiment prove that a draw frame equipped with multi-AGV and coordinated scheduling optimization will significantly improve the efficiency of can distribution. Flow-shop predictive modeling for multi-AGV resources is scarce in the literature, even though this modeling also produces, for each AGV, a control mode and, if essential, a preventive maintenance plan.
The Multi-Station Based Variable Speed Limit Model for Realization on Urban Highway
Authors: Jeon Soobin , Park Chongmyung , Seo Dongmahn
Published: May 2020

Intelligent transport systems (ITS) are a convergence of information technology and transportation systems as seen in the variable speed limit (VSL) system. Since the VSL system controls the speed limit according to the traffic conditions, it can improve the safety and efficiency of a transport network. Many researchers have studied the real-time VSL (RVSL) algorithm based on real-time traffic information from multiple stations recording traffic data. However, this method can suffer from inaccurate selection of the VSL start station (VSS), incorrect VSL calculations, and is unable to quickly react to the changing traffic conditions. Unstable VSL systems result in more congestion on freeways. In this study, an enhanced VSL algorithm (EVSL) is proposed to address the limitations of the existing RVSL algorithm. This selects preliminary VSL start stations (pVSS), which is expected to end congestion using acceleration and allocates final VSSs for each congestion interval using selected pVSS. This controls the vehicles that entered the congestion area based on the selected VSS. We used four metrics to evaluate the performance of the proposed VSL (VSS stability assessment, speed control stability assessment, travel time, and shockwave), which were all enhanced when compared to the standard RVSL algorithm. In addition, the EVSL algorithm showed stable VSL performance, which is critical for road safety.
A Dynamically Reconfigurable BbNN Architecture for Scalable Neuroevolution in Hardware
Authors: García Alberto , Zamacola Rafael , Otero Andrés , de la Torre Eduardo
Published: May 2020

In this paper, a novel hardware architecture for neuroevolution is presented, aiming to enable the continuous adaptation of systems working in dynamic environments, by including the training stage intrinsically in the computing edge. It is based on the block-based neural network model, integrated with an evolutionary algorithm that optimizes the weights and the topology of the network simultaneously. Differently to the state-of-the-art, the proposed implementation makes use of advanced dynamic and partial reconfiguration features to reconfigure the network during evolution and, if required, to adapt its size dynamically. This way, the number of logic resources occupied by the network can be adapted by the evolutionary algorithm to the complexity of the problem, the expected quality of the results, or other performance indicators. The proposed architecture, implemented in a Xilinx Zynq-7020 System-on-a-Chip (SoC) FPGA device, reduces the usage of DSPs and BRAMS while introducing a novel synchronization scheme that controls the latency of the circuit. The proposed neuroevolvable architecture has been integrated with the OpenAI toolkit to show how it can efficiently be applied to control problems, with a variable complexity and dynamic behavior. The versatility of the solution is assessed by also targeting classification problems.
Foreign Object Detection for Electric Vehicle Wireless Charging
Authors: Xia Jinglin , Yuan Xinmei , Li Jun , Lu Sizhao , Cui Xinxu , Li Siqi , Fernández-Ramírez Luis M.
Published: May 2020

Wireless power transfer technology is being widely used in electric vehicle wireless-charging applications, and foreign object detection (FOD) is an important module that is needed to satisfy the transmission and safety requirements. FOD mostly includes two key parts: metal object detection (MOD) and living object detection (LOD), which should be implemented during the charging process. In this paper, equivalent circuit models of a metal object and a living object are proposed, and the FOD methods are reviewed and analyzed within a unified framework based on the proposed FOD models. A comparison of these detection methods and future challenges is also discussed. Based on these analyses, detection methods that employ an additional circuit for detection are recommended for FOD in electric vehicle wireless-charging applications.
A Sub-Threshold Differential CMOS Schmitt Trigger with Adjustable Hysteresis Based on Body Bias Technique
Authors: Radfar Sara , Nejati Ali , Bastan Yasin , Amiri Parviz , Maghami Mohammad Hossein , Nasrollahpour Mehdi , Hamedi-Hagh Sotoudeh
Published: May 2020

This paper presents a sub-threshold differential CMOS Schmitt trigger with tunable hysteresis, which can be used to enhance the noise immunity of low-power electronic systems. By exploiting the body bias technique to the positive feedback transistors, the hysteresis of the proposed Schmitt trigger is generated, and it can be adjusted by the applied bias voltage to the bulk terminal of the utilized PMOS transistors. The principle of operation and the main formulas of the proposed circuit are discussed. The circuit is designed in a 0.18-μm standard CMOS process with a 0.6 V power supply. Post-layout simulation results show that the hysteresis width of the Schmitt trigger can be adjusted from 45.5 mV to 162 mV where the ratio of the hysteresis width variation to supply voltage is 19.4%. This circuit consumes 10.52 × 7.91 μm2 of silicon area, and its power consumption is only 1.38 µW, which makes it a suitable candidate for low-power applications such as portable electronic, biomedical, and bio-implantable systems.
Comparison of an Off-Line Optimized Firing Angle Modulation and Torque Sharing Functions for Switched Reluctance Motor Control
Authors: Bober Peter , Ferková Želmíra
Published: May 2020

In this paper, a comparison of the simple firing angle modulation method (FAM) and the more advanced torque sharing function (TSF)-based control of switched reluctance motor (SRM) is presented. The off-line procedure to tailor and optimize the parameters of chosen methods for off-the-shelf SRM is explained. Objective functions for optimization are motor efficiency, torque ripple, and integral square error. The off-line optimization uses a finite element method (FEM) model of the SRM. The model was verified by measurement on the SRM. Simulation results showed that FAM has comparable efficiency to TSF, but has a much higher value of torque ripple. The presented off-line procedure can be used for single or multi-objective optimization.
A Coordinated Voltage and Reactive Power Control Architecture for Large PV Power Plants
Authors: Chiandone Massimiliano , Campaner Riccardo , Bosich Daniele , Sulligoi Giorgio
Published: May 2020

The increasing presence of nonprogrammable renewable energy sources (RES) forces towards the development of new methods for voltage control. In the case of centralized generation, the hierarchical regulation or secondary voltage regulation (SVR) is guaranteed by coordinated voltage and reactive power controls in transmission systems. This type of regulation loses effectiveness when the generation becomes distributed and based on small and medium sized generators. To overcome this problem, it is important that also distributed generators, typically based on RES, participate in the voltage regulation. By starting from the methodologies already applied, this work wants to present a new method for involving distributed generators in SVR. The novelty is given by the application of an existing methodology to the new configuration of electrical grids characterized by a relevant distributed generation. The aim is to control the distributed generators (DGs) as coordinated sources of reactive power for conveniently supporting the voltage regulation. In this paper, a real large photovoltaic (PV) plant is considered. The power plant is composed of several PV generators connected through a distribution network. With the algorithm proposed, the set of generators can be treated as a single traditional power plant that can participate in the hierarchical voltage regulation. The reactive power of each single generator is coordinated in a way similar to the SVR used in several national systems.
A Paper-Based Microfluidic Fuel Cell Using Soft Drinks as a Renewable Energy Source
Authors: Hernández Rivera Jaime , Ortega Díaz David , Amaya Cruz Diana María , Rodríguez-Reséndiz Juvenal , Olivares Ramírez Juan Manuel , Dector Andrés , Dector Diana , Galindo Rosario , Esparza Ponce Hilda Esperanza
Published: May 2020

The research aims were to construct an air-breathing paper-based microfluidic fuel cell (paper-based μ FC) and to evaluated it with different soft drinks to provide energy for their prospective use in portable devices as an emergency power source. First, in a half-cell configuration, cyclic voltammetry showed that glucose, maltose, and fructose had specific oxidation zones in the presence of platinum-ruthenium on carbon (PtRu/C) when they were individual. Still, when they were mixed, glucose was observed to be oxidized to a greater extent than fructose and maltose. After, when a paper-based μ FC was constructed, PtRu/C and platinum on carbon (Pt/C) were used as anode and cathode, the performance of this μ FC was mostly influenced by the concentration of glucose present in each soft drink, obtaining maximum power densities at room temperature of 0.061, 0.063, 0.060, and 0.073 mW cm − 2 for Coca Cola ® , Pepsi ® , Dr. Pepper ® , and 7up ® , respectively. Interestingly, when the soft drinks were cooled, the performance was increased up to 85%. Furthermore, a four-cell stack μ FC was constructed to demonstrate its usefulness as a possible power supply, obtaining a power density of 0.4 mW cm − 2 , using Coca Cola ® as fuel and air as oxidant. Together, the results of the present study indicate an alternative application of an μ FC using soft drinks as a backup source of energy in emergencies.
Investigation of Ultra-High Pressure Gas Control System for Hydrogen Vehicles
Authors: Kim Roh-Won , Hwang Kyung-Hwan , Kim Sung-Ryul , Lee Jae-Hak
Published: May 2020

With the increasing demand to find new energy resources instead of using fossil fuels, for the protection of the environment, one of most attractive areas in renewable energy is hydrogen. Hydrogen gas has high energy efficiency, generates the least greenhouse gases and produces no noise. Moreover, overland transportation industries have been researching and developing hydrogen gas storage systems worldwide. Such a manner of fuel system consists of a hydrogen gas tank, high pressure regulator and solenoid valve, etc. In this paper, a test bed is suggested for ultra-high pressure systems integrating a valve and regulator with precision control. We carried out performance tests by applying voltage with wide ranges of input pressure, response time and output flow rate and pulsation repetition tests considering increases in temperature, etc. Moreover, the results indicated good potential for application in fuel charging and transporting commercial hydrogen vehicles.
A Case Study of the Supercritical CO2-Brayton Cycle at a Natural Gas Compression Station
Authors: Kowalski Rafał , Kuczyński Szymon , Łaciak Mariusz , Szurlej Adam , Włodek Tomasz
Published: May 2020

Heat losses caused by the operation of compressor units are a key problem in the energy efficiency improvement of the natural gas compression station operation. Currently, waste heat recovery technologies are expensive and have low efficiency. One of these technologies is organic Rankine cycle (ORC) which is often analyzed in scientific works. In this paper, the authors decided to investigate another technology that allows for the usage of the exhaust waste energy—the supercritical Brayton cycle with CO2 (S-CO2). With a thermodynamic model development of S-CO2, the authors preformed a case study of the potential S-CO2 system at the gas compressor station with the reciprocating engines. By comparing the values of selected S-CO2 efficiency indicators with ORC efficiency indicators at the same natural gas compression station, the authors tried to determine which technology would be better to use at the considered installation. Investigations on parameter change impacts on the system operation (e.g., turbine inlet pressure or exhaust gas cooling temperatures) allowed to determine the direction for further analysis of the S-CO2 usage at the gas compressor station. When waste heat management is considered, priority should be given to its maximum recovery and cost-effectiveness.
Thermal Transport in Nonlinear Unsteady Colloidal Model by Considering the Carbon Nanomaterials Length and Radius
Authors: Mohyud-Din Syed Tauseef , Adnan  , Abdeljawad T. , Khan Umar , Ahmed Naveed , Khan Ilyas
Published: May 2020

Thermal transport analysis in colloidal suspension is significant from industrial, engineering, and technological points of view. It has numerous applications comprised in medical sciences, chemical and mechanical engineering, electronics, home appliances, biotechnology, computer chips, detection of cancer cells, microbiology, and chemistry. The carbon nanomaterials have significant thermophysical characteristics that are important for thermal transport. Therefore, the thermal transport in H2O composed by single and multiwalled carbon nanotubes is examined. The length and radius of the nanomaterials is in range of 3 μm ≤ L* ≤ 70 μm and 10 nm ≤ d ≤ 40 nm, respectively. The problem is modelled over a curved stretching geometry by inducing the velocity slip and thermal jump conditions. The coupling of Runge-Kutta (RK) and shooting technique is adopted for the solution. From the analysis it is perceived that the heat transfer at the surface drops for stretching. The heat transfer rate prevailed for Single walled carbon nanotubes SWCNTs-H2O colloidal suspension. The suction and stretching of the surface resist the shear stresses and more shear stress trends are investigated for larger curvature.
Predictive Control for Microgrid Applications: A Review Study
Authors: Villalón Ariel , Rivera Marco , Salgueiro Yamisleydi , Muñoz Javier , Dragičević Tomislav , Blaabjerg Frede
Published: May 2020

Microgrids need control and management at different levels to allow the inclusion of renewable energy sources. In this paper, a comprehensive literature review is presented to analyse the latest trends in research and development referring to the applications of predictive control in microgrids. As a result of this review, it was found that the application of predictive control techniques on microgrids is performed for the three control levels and with adaptations of the models in order to include uncertainties to improve their performance and dynamics response. In addition, to ensure system stability, but also, at higher control levels, coordinated operation among the microgrid’s components and synchronised and optimised operation with utility grids and electric power markets. Predictive control appears as a very promising control scheme with several advantages for microgrid applications of different control levels.
Evaluation of Performance and Technological Characteristics of Battery Electric Logistics Vehicles: China as a Case Study
Authors: Jiang Xiaohong , Guo Xiucheng
Published: May 2020

The powertrain characteristics of battery electric logistics vehicles (BELVs) are extremely suited for the urban driving context and have a higher environmental protection potential for sustainable development, which can provide solutions for urban logistics decarbonization. The BELV is an important part of the Chinese national new-energy vehicle program, and the market penetration of BELVs has greatly improved. However, BELVs still have many technical shortcomings, which seriously affect their widespread acceptance. Therefore, it is necessary to reveal the technological characteristics and development direction of BELVs based on a large amount of marketing and technological data. This research reviewed the Chinese incentive policies and industrialization progress of BELVs. An evaluation system comprising 8 technological indicators for evaluating BELV technological progress was proposed. The distribution characteristics of the curb mass, vehicle volume, all-electric range, top speed, driving power, energy efficiency, traction battery and motor technology were analyzed for 2017 and 2019 markets’ models. The vehicle total cost, vehicle performance and reliability of BELVs are not advantageous yet. However, all the performance parameters are improving year by year, constantly meeting logistics demands. The subsidies are needed for longer for the market to mature. Finally, several suggestions for the technical development direction of BELVs were proposed. All these results can be used to improve the vehicle performance, reliability and market penetration of BELVs.
The Role of Powertrain Electrification in Achieving Deep Decarbonization in Road Freight Transport
Authors: González Palencia Juan C. , Nguyen Van Tuan , Araki Mikiya , Shiga Seiichi
Published: May 2020

Decarbonizing road freight transport is difficult due to its reliance on fossil fuel internal combustion engine vehicles (ICEVs). The role of powertrain electrification in achieving deep decarbonization in road freight transport was studied using a vehicle stock turnover model, focusing on Japan. Twelve vehicle types were considered; combining four powertrains, ICEV, hybrid electric vehicle (HEV), battery electric vehicle (BEV) and fuel cell electric vehicle (FCEV); and three vehicle size classes, normal, compact and mini-sized vehicles. A scenario-based approach was used; considering a Base scenario, and three alternative scenarios targeting powertrain electrification. Between 2012 and 2050, tank to wheel CO2 emissions decrease 42.8% in the Base scenario, due to the reduction of vehicle stock, the improvement of vehicle fuel consumption and the adoption of HEVs. Diffusion of FCEVs in normal vehicles and BEVs in compact and mini-sized vehicles achieves the largest tank to wheel CO2 emissions reductions, up to 44.6% compared with the 2050 baseline value. The net cash flow is positive over the whole time horizon, peaking at 6.7 billion USD/year in 2049 and reaching 6.6 billion USD/year by 2050. Powertrain electrification is not enough to achieve any of the CO2 emissions reduction targets in road freight transport.
Discussion on Determination Method of Long-Term Strength of Rock Salt
Authors: Ding Guosheng , Liu Jianfeng , Wang Lu , Wu Zhide , Zhou Zhiwei
Published: May 2020

Due to the extremely low permeability and the excellent creep behavior, rock salt is the optimal surrounding rock of underground energy storage. The long-term safe operation of the rock salt energy storage is closely related to the creep behavior and long-term strength of rock salt, but few researches focus on the long-term strength of rock salt. In order to more accurately predict the long-term strength of rock salt, the isochronous stress–strain curve method and the volume expansion method for determining the long-term strength were analyzed and discussed based on axial compression tests and axial creep tests. The results show that the isochronous stress–strain curve method is intuitive but will greatly increase the test cost and test time to obtain a satisfactory result. The volume expansion method is simple, but the long-term strength obtained according to the inflection point of volumetric strain is much greater than the actual long-term strength of rock salt. Therefore, a new method applicable to rock salt was proposed based on the evolution of damage in rock salt in this paper, which takes the corresponding stress value at the damage initiation point as the long-term strength. The long-term strength determined by this method is consistent with that by the isochronous stress–strain curve method. The method is more economical and convenient and aims to provide a reference for the long-term stability study of underground salt caverns.
Controlled Impedance-Admittance-Torque Nonlinear Modeling and Analysis of Modern Power Systems
Authors: C. Papageorgiou Panos , Alexandridis Antonio T.
Published: May 2020

Modern power systems are continuously transformed into decentralized ones where distributed generation (DG) plays a key role. Almost all the different distributed energy resources (DERs) are connected in geographically dispersed places through controlled power electronic interfaces in a manner that essentially affects the dynamic performance and control of the whole power system. Simultaneously, rotating machines in power production or absorption, dominate the system response and stability. In this new frame, this paper proposes a novel generalized dynamic representation and full scale modeling of a modern power system based on the well-known impedance-admittance (IA) network model for the electricity grid, substantially extended to include in detail both the power converter devices by considering the controlled power electronic dynamics and the electrical machines by inserting their full electromechanical dynamics. This formulation results in a holistic nonlinear dynamic description, defined here as controlled impedance-admittance-torque (CIAT) model of the whole system which features common structural characteristics. The model is deployed in state space, involves all the controlled inputs in DG, namely the duty-ratio signals of each power converter interface, all the other external inputs affecting the system, namely all the known or unknown voltage, current, and torque inputs. As shown in the paper, the proposed CIAT model retains its fundamental properties for any DG and network topology, standard or varying. This enables the compression of the accurate analytic power system dynamic description into a matrix-based generic nonlinear model that can be easily used for analysis studies of such large-scale systems. Taking into account the nonlinear nature of the CIAT matrix-based model and the persistent action of the external inputs, Lyapunov methods deployed on recently established input to state stability (ISS) notions are systematically applied for the system analysis. Hence, the traditionally used small-signal model-based analysis that suffers from the intermittent and continuously changing operation of DERs is completely substituted by the proposed formulation. A modern power system example with different DERs involved is analyzed by this way and is extensively simulated to verify the validity of the proposed method.
Preparation and Properties of Capric–Myristic Acid/Expanded Graphite Composite Phase Change Materials for Latent Heat Thermal Energy Storage
Authors: Zhou Dongyi , Yuan Jiawei , Zhou Yuhong , Liu Yicai
Published: May 2020

A novel composite phase change material (CPCM), capric–myristic acid/expanded graphite (CA–MA/EG) CPCM, was prepared by absorbing liquid CA–MA (as the phase change material (PCM)) into EG (as the substrate material) for heat storage in the backfill materials of soil-source heat pump systems. The thermal characteristics and microstructure of the novel CPCM were analyzed using differential scanning calorimetry (DSC) and scanning electronic microscopy (SEM). The thermal conductivities of CA–MA/EG CPCM were surveyed. The thermal stability of the CA–MA/EG was analyzed using thermogravimetric analysis (TGA) and thermal cycle tests. The results showed that the optimal mass content of CA–MA in CPCM was approximately 92.4% and the CA–MA was uniformly distributed in the vesicular structure of EG; the CA–MA/EG CPCM had an appropriate phase change temperature (Tm: 19.78 °C, Tf: 18.85 °C), high latent heat (Hm: 137.3 J/g, Hf: 139.9 J/g), and excellent thermostability and thermal reliability. The thermal conductivity of the CPCM was remarkably enhanced after adding EG. Therefore, the CPCMs demonstrated outstanding thermal performance and can be utilized in low-temperature latent heat thermal energy storage (LHTES) systems, such as soil-source heat pump systems.
Research on Environmental Sustainability of Coal Cities: A Case Study of Yulin, China
Authors: Zhai Xiaowei , Cheng Zhuo , Ai Keyu , Shang Bo
Published: May 2020

Coal cities are an essential impetus for economic development and urbanization processes in China. However, a series of environmental issues provoked by resource exploitation cause the environmental sustainability of coal cities to face enormous challenges. Therefore, on the basis of the time series data of Yulin City from 1996 to 2017, this paper explores the nexus between socioeconomic development and industrial “three wastes” emissions by adopting the Tapio decoupling model, the environmental Kuznets curve (EKC) hypothesis, and the vector auto-regressive (VAR) model. The results show that Yulin’s economic development remains in an extensive stage and will not decouple from the environmental pollution in a short time. Except for the nexus of industrial solid waste and economic growth, which is an inverted U-shaped, the EKC hypothesis is not valid for industrial wastewater and industrial waste gas. Through the VAR (2) model, the impact of per capita gross domestic product (GDP) on industrial waste emissions is consistent with the results of the EKC hypothesis. Moreover, industrial waste emissions have a positive correlation with the per capita raw coal output, the energy consumption per unit of GDP, and the proportion of secondary industry. Hence, it is necessary to formulate targeted measures from industrial restructuring, industrial chain extension, governance model optimization, and waste comprehensive utilization to realize the environmental sustainability of coal cities.
Geometry-Load Based Hybrid Correction Method for the Pre-Deformation Design of a Steam Turbine Blade
Authors: Yi Guodong , Zhou Huifang , Qiu Lemiao , Wu Jundi
Published: May 2020

To solve the problem of the slow convergence of the geometry-based correction (GC) method in the design of a steam turbine blade, this paper proposes a geometry-load-based hybrid correction (GLHC) method. In this method, the deformation of the blade caused by the centrifugal load is still corrected by the GC method, while the deformation caused by the aerodynamic load is corrected by the load-based correction (LC) method instead of the GC method. The LC method updates the cold shape of the blade by reversely applying the aerodynamic load to the ideal shape according to the balance between the internal force generated by the deformation of the blade and the aerodynamic load acting on surface of the hot blade shape, thereby reducing the number of iterations by reducing the shape deviation in each step of the iteration. The GLHC method, which combines the GC and LC methods, is used to improve the design process. The efficiency of the GLHC and GC methods are compared with the maximum number of position deviations of the corresponding mesh nodes between the hot blade and ideal blade shapes, which acts as the criterion. The results show that the GLHC method reduces the number of iterations.
A Comprehensive Review on Bypass Diode Application on Photovoltaic Modules
Authors: Vieira Romênia , de Araújo Fábio , Dhimish Mahmoud , Guerra Maria
Published: May 2020

Solar photovoltaic (PV) energy has shown significant expansion on the installed capacity over the last years. Most of its power systems are installed on rooftops, integrated into buildings. Considering the fast development of PV plants, it has becoming even more critical to understand the performance and reliability of such systems. One of the most common problems faced in PV plants occurs when solar cells receive non-uniform irradiance or partially shaded. The consequences of shading generally are prevented by bypass diodes. A significant number of studies and technical reports have been published as of today, based on extensive experience from research and field feedbacks. However, such material has not been cataloged or analyzed from a perspective of the technological evolution of bypass diodes devices. This paper presents a comprehensive review and highlights recent advances, ongoing research, and prospects, as reported in the literature, on bypass diode application on photovoltaic modules. First, it outlines the shading effect and hotspot problem on PV modules. Following, it explains bypass diodes’ working principle, as well as discusses how such devices can impact power output and PV modules’ reliability. Then, it gives a thorough review of recently published research, as well as the state of the art in the field. In conclusion, it makes a discussion on the overview and challenges to bypass diode as a mitigation technique.
Prediction of Health-Related Leave Days among Workers in the Energy Sector by Means of Genetic Algorithms
Authors: González Fuentes Aroa , Busto Serrano Nélida M. , Sánchez Lasheras Fernando , Fidalgo Valverde Gregorio , Suárez Sánchez Ana
Published: May 2020

In this research, a model is proposed for predicting the number of days absent from work due to sick or health-related leave among workers in the industry sector, according to ergonomic, social and work-related factors. It employs selected microdata from the Sixth European Working Conditions Survey (EWCS) and combines a genetic algorithm with Multivariate Adaptive Regression Splines (MARS). The most relevant explanatory variables identified by the model can be included in the following categories: ergonomics, psychosocial factors, working conditions and personal data and physiological characteristics. These categories are interrelated, and it is difficult to establish boundaries between them. Any managing program has to act on factors that affect the employees’ general health status, process design, workplace environment, ergonomics and psychosocial working context, among others, to achieve success. This has an extensive field of application in the energy sector.
Aquifer Thermal Energy Storage (ATES) for District Heating and Cooling: A Novel Modeling Approach Applied in a Case Study of a Finnish Urban District
Authors: Todorov Oleg , Alanne Kari , Virtanen Markku , Kosonen Risto
Published: May 2020

Aquifer thermal energy storage (ATES) combined with ground-source heat pumps (GSHP) offer an attractive technology to match supply and demand by efficiently recycling heating and cooling loads. This study analyses the integration of the ATES–GSHP system in both district heating and cooling networks of an urban district in southwestern Finland, in terms of technoeconomic feasibility, efficiency, and impact on the aquifer area. A novel mathematical modeling for GSHP operation and energy system management is proposed and demonstrated, using hourly data for heating and cooling demand. Hydrogeological and geographic data from different Finnish data sources is retrieved in order to calibrate and validate a groundwater model. Two different scenarios for ATES operation are investigated, limited by the maximum pumping flow rate of the groundwater area. The additional precooling exchanger in the second scenario resulted in an important advantage, since it increased the heating and cooling demand covered by ATES by 13% and 15%, respectively, and decreased the energy production cost by 5.2%. It is concluded that dispatching heating and cooling loads in a single operation, with annually balanced ATES management in terms of energy and pumping flows resulted in a low long-term environmental impact and is economically feasible (energy production cost below 30 €/MWh).
Nickel Salicylaldoxime-Based Coordination Polymer as a Cathode for Lithium-Ion Batteries
Authors: Beletskii Evgenii V. , Lukyanov Daniil A. , Vlasov Petr S. , Yankin Andrei N. , Atangulov Arslan B. , Sizov Vladimir V. , Levin Oleg V.
Published: May 2020

Conjugated coordination polymers attract attention as materials for electrochemical energy storage, mostly as cathode materials for supercapacitors. Faradaic capacity may be introduced to such materials using redox-active building blocks, metals, or ligands. Using this strategy, a novel hybrid cathode material was developed based on a Ni2+ metal-organic polymer. The proposed material, in addition to double-layer capacitance, shows high pseudocapacitance, which arises from the contributions of both the metal center and ligand. A tailoring strategy in the ligand design allows us to minimize the molecular weight of the ligand, which increases its gravimetric energy. According to computational results, the ligand makes the prevailing contribution to the pseudocapacitance of the material. Different approaches to metal–organic polymer (MOP) synthesis were implemented, and the obtained materials were examined by FTIR, Raman spectroscopy, powder XRD, SEM/EDX (energy-dispersive X-ray spectroscopy), TEM, and thermal analysis. Energy-storage performance was comparatively studied with cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD). As a result, materials with an excellent discharge capacity were obtained, reaching the gravimetric energy density of common inorganic cathode materials.
High Recovery of Saplings after Severe Drought in Temperate Deciduous Forests
Authors: Beloiu Mirela , Stahlmann Reinhold , Beierkuhnlein Carl
Published: May 2020

Drought episodes are predicted to increase their intensity and frequency globally, which will have a particular impact on forest vitality, productivity, and species distribution. However, the impact of tree species interaction on forest vulnerability to drought is not yet clear. This study aims to assess how deciduous saplings react to drought and whether tree species diversity can buffer the impact of drought stress on tree saplings. Based on field measurements of crown defoliation and species diversity, vulnerability, drought recovery, and species interaction were analyzed. Fieldwork was carried out in Central Eastern Germany in 2018 during the vegetation season and repeated in 2019. Ten random saplings were measured in each of the 218 plots (15 × 15 m) with 2051 saplings in total out of 41 tree species. We found that 65% of the saplings experienced defoliation during the drought of 2018, of which up to 13% showed complete defoliation. At the species level, Fagus sylvatica L. and Betula pendula Roth. saplings were less affected (<55%), whereas Carpinus betulus L., Sorbus aucuparia L., and Frangula alnus Mill. saplings were the most affected (≥85%). One year later, in 2019, C. betulus and S. aucuparia had a faster recovery rate than F. sylvatica, B. pendula, Quercus spp., and Crataegus spp. (p < 0.001). Furthermore, we showed that forest stands with high sapling species diversity had a reduced vitality under drought stress (p < 0.001), indicating a higher competition for resources. The study provides evidence that F. sylvatica saplings can withstand and survive to persistent drought. Species-specific responses to drought are essential to be considered for implementing adaptive forest management strategies to mitigate the impact of climate change.
Identifying Local-Scale Weather Forcing Conditions Favorable to Generating Iberia’s Largest Fires
Authors: Vieira Inês , Russo Ana , M. Trigo Ricardo
Published: May 2020

The Mediterranean region is characterized by the frequent occurrence of summer wildfires, representing an environmental and socioeconomic burden. Some Mediterranean countries (or provinces) are particularly prone to large fires, namely Portugal, Galicia (Spain), Greece, and southern France. Additionally, the Mediterranean basin corresponds to a major hotspot of climate change, and anthropogenic warming is expected to increase the total burned area due to fires in Mediterranean Europe. Here, we propose to classify summer large fires for fifty-four provinces of the Iberian Peninsula according to their local-scale weather conditions and fire danger weather conditions. A composite analysis was used to investigate the impact of local and regional climate drivers at different timescales, and to identify distinct climatologies associated with the occurrence of large fires. Cluster analysis was also used to identify a limited set of fire weather types, each characterized by a combination of meteorological conditions. For each of the provinces, two significant fire weather types were identified—one dominated by high positive temperature anomalies and negative humidity anomalies, and the other by intense zonal wind anomalies with two distinct subtypes in the Iberian Peninsula., allowing for the identification of three distinct regions.
Wood Protection and Preservation
Authors: Brischke Christian
Published: May 2020

Wood is an advantageous building material in many respects, but it is biodegradable and therefore requires protection when used in highly hazardous applications. This Special Issue on ‘Wood Protection and Preservation’ comprises 19 papers representing a wide range of aspects related to the field and gives timely examples of research activities that can be observed around the globe.
RETRACTED: Propensities of Old Growth, Mature and Regrowth Wet Eucalypt Forest, and Eucalyptus nitens Plantation, to Burn During Wildfire and Suffer Fire-Induced Crown Death
Authors: Winoto-Lewin Suyanti , Sanger Jennifer , Kirkpatrick James
Published: May 2020

There are conflicting conclusions on how the flammability of wet eucalypt forests changes in the time after disturbances such as logging or wildfire. Some conclude that forests are most flammable in the decades following disturbance, while others conclude that disturbance has no effect on flammability. The comparative flammability of Eucalyptus nitens plantations in the same environment as wet eucalypt forest is not known. We determined fire incidence and fire severity in regrowth, mature and old growth wet eucalypt forest, and E. nitens plantation, in the Huon Valley, Tasmania after the January–February 2019 wildfire. To control for topographic variation and fire weather, we randomly selected sites within the fire footprint, then randomly located a paired site for each in different forest types in the same topographic environment within 3 km. Each pair of sites was burned on the same day. Old growth forest and plantations were the least likely to burn. Old growth and mature forest exhibited scorched eucalypt crowns to a much lesser degree than regrowth forests. In a comparison of paired sites, plantation forest was less likely to burn than combined mature and old growth forests, but in all cases of detected ignition the canopy of plantation was scorched. The lower flammability of older forests, and their importance as an increasing store of carbon, suggests that a cessation of logging outside plantations might have considerable benefits.