Optimizing traffic signals to improve traffic progression relies on minimizing mobility performance measures (e.g., delays and stops). However, delay and stop minimizations do not necessarily lead to minimal sustainability measures (e.g., fuel consumption and emissions). For that reason, researchers have focused, for decades, on integrating traffic models, signal optimization models, and fuel consumption and emissions models to minimize sustainability metrics while keeping acceptable levels of mobility metrics. Therefore, this paper reviews, classifies, and analyzes studies found in the literature regarding optimizing sustainable traffic signals. This paper provides researchers with a good starting point to further develop solutions which can address sustainable traffic control. To achieve that, this study details the most notable sustainable signal timing optimization studies from six perspectives: traffic models, fuel consumption and emissions models, optimization methods, objective... [more]

This paper shows a practice to raise the reliability of an electric power system by the installation of distributed generation, taking gasified biomass as fuel. To calculate the reliability index, a probabilistic load flow was used. This index is determined as the fault probability of the system. The resolution of this probabilistic load flow combines the method of cumulants and Gram−Charlier expansion. To achieve the reliability index, simulating a number of contingencies is required; the greater the number of simulated contingencies, the higher the accuracy of the index obtained. This probabilistic technique uses the random variables as starting information, so the two generators and loads are simulated as random variables. The generators of this distributed generation are biomass-fueled gas engines, commonly found in Spain. The simulations carried out on the IEEE 14-bus Test System, including three biomass generators, show that the inclusion of this type of generation improves the o... [more]

Due to the flexibility, sustainability, affordability, and ease of installation of solar photovoltaic systems, their use has significantly increased over the past two decades. The performance of a solar PV system can be constrained by a variety of external conditions, including hotspots, partial shade, and other minor faults. This causes the PV system to permanently fail and power losses. The power output in a partially shaded solar system is improved in this work by the introduction of a fault classifier based on thermal image analysis with a reconfiguration algorithm. For that purpose, the entire PV array is divided into two parts, with one of these being the male part and the other being the female part. MOSFET switches are used to build the switching matrix circuit that connects these parts. The Flir T420bx thermal camera captures thermal pictures, and MATLAB/Simulink® is used to extract the image properties. The pairing reconfiguration pattern is found using an algorithm based on... [more]

The trend towards the decentralization and decarbonization of the energy sector stimulates the adoption of generation facilities based on renewable energy sources (RES) and distributed generation (DG) facilities that utilize secondary energy resources. Operation features of DG facilities, such as a high speed of electromechanical transient processes and significant deviations of power quality indicators from standard values, require improvement and an increase in the speed of automation devices. Modern electroautomatic devices must determine the operating regions (normal and emergency) and adapt the operation algorithms to the conditions of the current mode. The study presented proposes methods developed to use the Wald Sequential Probability Ratio Test (WSPRT) to improve the reliability and efficiency of the power system automation devices. The paper provides examples of using WSPRT in the devices of automatic frequency load shedding, automatic transformer disconnection, and power qua... [more]

In this work, three raised expanded metal meshes (EMMs) differing in mesh size were tested experimentally with regard to their flow and transport properties. Empirical equations for the Nusselt number and Fanning friction factor were developed. Alongside the experiments, simple computational fluid dynamics (CFD) models were used to simulate the pressure drop and heat transfer coefficients within EMMs. Finally, the Performance Efficiency Criterion (PEC) was applied to compare EMMs with other reactor packings.

The mine return air flow has the characteristics of basically constant temperature and humidity all year round and is a high-quality waste heat resource. Its direct discharge not only wastes energy but also causes environment pollution. It has important economic value and application prospect to solve the problem of shaft antifreeze using new technology to recover the waste heat of mine return air. Gravity heat pipe is widely used in the heat recovery of mine return air. Its heat transfer process is a complex process with multiple parameters. The current research focuses on the influence of a single factor on heat transfer, which has many limitations. To analyze the effects of different parameters on the heat recovery effect of gravity heat pipe in mine return air and to optimize heat pipe heat exchanger parameters in the heat exchange system, mathematical models of gas−water countercurrent heat and mass transfer, entransy dissipation and exergy efficiency were established in this pape... [more]

Although almost all the shale gas in China is exploited from marine shale (Wufeng−Longmaxi Formation) in Sichuan Basin and several prolific wells, it has also been obtained in Jurassic lacustrine shale. However, the reservoir conditions of the lacustrine shale are not well understood, which has impeded a breakthrough regarding lacustrine shale gas in Sichuan Basin. To probe the reservoir conditions of the lacustrine shale in Sichuan Basin, we take the Wufeng−Longmaxi shale and Dongyuemiao shale sampled from wells and outcrops as examples. A series of experiments were conducted, including TOC, XRD, FE-SEM, N2 adsorption, Micro-CT, vitrinite reflectance and bitumen reflectance. The results show that the pores in marine shale are mainly composed of organic-matter-hosted pores (OM pores). However, in the lacustrine shale, the pores are mainly composed of dissolution pores and intergranular pores. The marine shale is characterized by small-caliber and large-volume pores in which cluster por... [more]

In HV cable fault location technology, line parameter uncertainty has an impact on the location criterion and affects the fault location result. Therefore, it is of great significance to study the uncertainty quantification of line parameters. In this paper, an impedance-based fault location criterion was used for an uncertainty study. Three kinds of uncertainty factors, namely the sheath resistivity per unit length, the equivalent grounding resistance on both sides, and the length of the cable section, were taken as random input variables without interaction. They were subject to random uniform distribution within a 50% amplitude variation. The relevant statistical information, such as the mean value, standard deviation and probability distribution, of the normal operation and fault state were calculated using the Monte Carlo simulation (MCS) method, the polynomial chaos expansion (PCE) method, and the univariate dimension reduction method (UDRM), respectively. Thus, the influence of... [more]

Buses are large vehicles with the primary goal of carrying as many passengers as possible while maintaining a comfortable interior and an economical driving cycle. With various adjustments, small changes can add up to significant energy savings. This study investigates the issue of whether there is a scenario in which the enormous power demand needed for the operation of buses can be reduced by some amount. Large eddy simulation was used for this analysis, which was carried out using commercially available software. The external unit was located on the front and rear ends of the roof of the bus, as well as in the rear. The findings suggest that the current position of the unit can be improved, and the aerodynamic losses can be increased or decreased, depending on the position of the induced flow.

The European Parliament’s climate and energy policy, which aims to cut greenhouse gas emissions by 2030 considerably, imposes on Member States the duty to develop National Action Plans (NAPs), which determine the percentage of renewable energy sources (RES) in gross energy consumption. Poland assumed a percentage of renewable energy sources in gross energy consumption of 21−23% in the NREAP. In 2020, Poland’s utilisation of renewable energy sources was 16.2% (22nd among EU nations), which was lower than the European average. The municipal sector, particularly sewage treatment facilities, can undoubtedly contribute to an increase in renewable energy generation and utilisation. Wastewater and sewage sludge are excellent sources of heat and energy in the methane fermentation process, and the sewage treatment plant area is perfect for solar panel installation. The article is a case study that presents the possibility of decreasing CO2 emissions from wastewater treatment facilities by 45,00... [more]

Coal is an important fossil fuel energy that occupies a high position in the energy use of China and even the world. However, gas explosions are still the deadliest coal mine accident in China, which has long plagued the safety of energy mining. Only through accident cause analysis can we know the exact cause of the accident so as to make targeted policies, safety trainings, etc. However, the lack of detailed accident cause classification in current coal mine gas explosion accidents affects the comprehensiveness and accuracy of energy mining safety strategies. Therefore, in this study, a classification method for coal mine gas explosion accident causes based on the sixth edition 24Model and the three-element classification of gas explosions was proposed. Then, the consistency and validity of the newly established classification system were evaluated based on the three indicators, i.e., observer consistency, content validity, and criterion validity, and the performance of the classifica... [more]

Accurate electricity price forecasting (EPF) can provide a necessary basis for market decision making by power market participants to reduce the operating cost of the power system and ensure the system’s stable operation. To address the characteristics of high frequency, strong nonlinearity, and high volatility of electricity prices, this paper proposes a short-term electricity price forecasting model based on a two-layer variational modal decomposition (VMD) technique, using the sparrow search algorithm (SSA) to optimize the long and short-term memory network (LSTM). The original electricity price sequence is decomposed into multiple modal components using VMD. Then, each piece is predicted separately using an SSA-optimized LSTM. For the element with the worst prediction accuracy, IMF-worst is decomposed for a second time using VMD to explore the price characteristics further. Finally, the prediction results of each modal component are reconstructed to obtain the final prediction resu... [more]

Ferroelectric oxides possess abundant fascinating physical functionalities, such as electro-optic, acousto-optic, and nonlinear optical characteristics, etc. However, most pristine ferroelectric oxides exhibit no efficient luminescent properties due to the indirect and wide bandgap. Rare-earth-doped phosphors demonstrate advantages such as sharp emission bandwidths, large Stokes shift, high photonstability, and low toxicity. The combination of rare-earth ions and ferroelectric oxides has shown great potential in optical sensing, lighting, solar cells, and other applications. Rare-earth-doped ferroelectric oxides exhibit efficient upconversion or downconversion luminescence in the range of ultraviolet (UV) to near-infrared (NIR) regions. In this article, the preparation process of rare-earth-doped ferroelectric oxides and the preparation methods of thin films are introduced. Their recent applications in optical sensing, lighting, and solar cells are highlighted. The review concludes wit... [more]

Battery management systems (BMS) are important for ensuring the safety, efficiency and reliability of a battery pack. Estimating the internal equivalent circuit model (ECM) parameters of a battery, such as the internal open circuit voltage, battery resistance and relaxation parameters, is a crucial requirement in BMSs. Numerous approaches to estimating ECM parameters have been reported in the literature. However, existing approaches consider ECM identification as a joint estimation problem that estimates the state of charge together with the ECM parameters. In this paper, an approach is presented to decouple the problem into ECM identification alone. Using the proposed approach, the internal open circuit voltage and the ECM parameters can be estimated without requiring the knowledge of the state of charge of the battery. The proposed approach is applied to estimate the open circuit voltage and internal resistance of a battery.

The COVID-19 pandemic is undoubtedly a destructive factor, strongly affecting the economic fields. From the perspective of the countries affected by the pandemic, almost all sectors of the economy saw declines in economic indicators. First, the lockdown and its social consequences contributed to this. The increasing time perspective since the outbreak of the COVID-19 pandemic implies increasingly more studies analyzing its impact on various economic spheres. The aim of the research is to determine the difference in the level of fuel supplies between a pandemic situation and a situation where a pandemic would not occur. We assumed that the pandemic is a determinant of the decline in fuel supplies. The subjects of the analysis were the following fuels: kerosene-type jet fuel, gas oil and diesel oil, motor gasoline, and oil products. The countries of the European Union were analyzed. Monthly data from 2015−2021 provided by Eurostat were used for the analyses. The forecasts for 2020−2021 w... [more]

Due to their attractive properties, such as high energy and power density, Lithium-ion batteries are currently the most suitable energy storage system for powering portable electronic equipment, electric vehicles, etc. However, they are still affected by safety and stability problems that need to be solved to allow a wider range of applications, especially for critical areas such as power networks and aeronautics. In this paper, the issue of overdischarge abuse has been addressed on Lithium-ion cells with different anode materials: a graphite-based anode and a Lithium Titanate Oxide (LTO)-based anode model. Tests were carried out at different depths of discharge (DOD%) in order to determine the effect of DOD% on cell performance and the critical conditions that often make the cell fail irreversibly. Tests on graphite anode cells have shown that at DOD% higher than 110% the cell is damaged irreversibly; while at DOD% lower than 110% electrolyte deposits form on the anodic surface and st... [more]

We investigate whether oil-price uncertainty helps forecast the international stock returns of ten advanced and emerging countries. We consider an out-of-sample period of August 1925 to September 2021, with an in-sample period between August 1920 and July 1925, and employ a quantile-predictive-regression approach, which is more informative relative to a linear model, as it investigates the ability of oil-price uncertainty to forecast the entire conditional distribution of stock returns Based on a recursive estimation scheme, we draw the following main conclusions: the quantile-predictive-regression approach using oil-price uncertainty as a predictor statistically outperforms the corresponding quantile-based constant-mean model for all ten countries at certain quantiles (capturing normal, bear, and bull markets), and over specific forecast horizons, compared to forecastability being detected for eight countries under the linear predictive model. Importantly, we detect forecasting gains... [more]

Integrated reporting (IR) contains a lot of important information for firms, such as income, cash flows, risks, uncertainties, intellectual capital, social capital and environmental capital. Based on the relevant literature it is found that the adoption of integrated reporting affects the firms’ value in the short, medium and long term and, at the same time affects its environmental, social and governance performances. The aim of this paper is to analyze the impact of integrated reporting in European energy firms’ value relevance. To do so, the panel data concerning 38 European energy distribution listed firms are analyzed, using statistical and econometrical methods including OLS, WLS, fixed effects and random effects models. The paper’s main novelty is that it concerns a sector that plays a key role in the economic development of countries and, at the same time only a few studies are carried out concerning the examined subject in this sector. The research results have revealed that i... [more]

This research paper presents a review of the state of the art of desalination in Mexico, with the aim of clarifying the main challenges and opportunity areas for desalination as the main solution to overcome water stress. First, the current situation and forecasts on the availability of water resources in Mexico are described, followed by the main economic, social, and legislative issues of desalination. Mexico’s installed capacity for the different desalination technologies and their evolution in recent years was investigated, followed by a comparison with global trends. The current state of research and development in desalination technologies carried out by Mexican institutions was also studied. The results show that membrane technology plants account for 88.85%, while thermal technology plants account for the remaining 11.15%. Although Mexico presented a 240% increase in its desalination capacity in the last 10 years, it has not been enough to overcome water stress, so it is conclu... [more]

Although the energy change field in the centrifugal pump has been investigated under quasi-steady conditions (QSC), equivalent information is not yet known during the rapid starting period (RSP). A centrifugal pump loop system is constructed to investigate the energy change field in the centrifugal pump during RSP. The RSP is selected as a linear rotational speed from 0 rev/min to 2900 rev/min (design rotational speed) and a constant valve opening of 0.569. Results show that the flow rate lags behind the pump head value with the linear increase in rotational speed. The large values of partial derivations of mechanical energy in normal and tangential components are mainly concentrated at the impeller outlet, whose position is insensitive to rotational speed. The region of dominant energy loss is negatively correlated with rotational speed, and an opposite phenomenon is observed in the region of dominant energy increase. With the rotational speed increasing, the mean energy gradient func... [more]

Increasing environmental problems and the energy crisis have led to interest in the development of alternative energy. One of the most promising sustainable alternatives to fossil fuel is biodiesel which is typically produced from the transesterification of refined vegetable oils using a homogeneous base catalyst. However, the current process limitations and steep production costs associated with the use of homogeneous catalysts have limited the global-wide acceptance of biodiesel. Heterogeneous catalysts have been considered suitable alternatives, but they still suffer from low catalytic activity. In this study, by using density functional theory (DFT) calculations, we examined the electronic and catalytic activity of the single Na-doped graphitic carbon nitrides (indicated by Na-doped g-C3N4) toward the efficient biodiesel (acetic acid methyl ester) production via the transesterification of triglyceride (triacetin). Our DFT calculation on reaction energetics and barriers revealed the... [more]

The application of microgrids (MG) is more and more extensive, therefore it is important to improve the system management method of microgrids. The intended costs can be further minimized when the energy management system is unified with demand side response (DSR) strategies. In this work, we propose a generic method of modeling the equipment in a microgrid including multiple stochastic loads. The microgrid model can be generated on a computer by converting the energy circuit diagram into a signal flow diagram. Then, a demand side response method based on binomial distribution is introduced, and loads are set to different probabilities according to importance. By applying the probability of loads and changing the return coefficient of loads, the problem of individual differences in demand side responses is solved, so as to improve consumer satisfaction. The proposed model is constructed as a mixed-integer linear program (MILP). Cases studies demonstrate feasibility of the proposed mode... [more]

To meet the requirements of today’s fast-growing Li-ion battery market, cell production depends on cheap, fast and reliable methods. Lamination of electrodes and separators can accelerate the time-consuming stacking step in pouch cell assembly, reduce scrap rate and enhance battery performance. However, few laminable separators are available on the market so far. This study introduces electrospinning as a well-suited technique to apply thin functional polymer layers to common battery separator types, enabling lamination. The method is shown to be particularly appropriate for temperature resistant ceramic separators, for which stable interfaces between separator and electrodes were formed and capacity fading during 600 fast charging cycles was reduced by 44%. In addition, a straightforward approach to apply the method to other types of separators is presented, including separator characterization, coating polymer selection, mechanical tests on intermediates and electrochemical validatio... [more]

The rotor permanent magnet flux-switching (RPM-FS) machine is a promising candidate for electric vehicle (EV) and hybrid electric vehicle (HEV) applications. In this paper, we propose the magnetic flux barrier design to improve the torque capability of the RPM-FS machine. The response surface optimization method was used to design and optimize the topology of flux barriers. The 2D finite element analysis shows that the proposed RPM-FS machine has a higher electromotive force than the conventional structure, with only a slight increase in cogging torque. Notably, an insertion of flux barriers could yield a reduction of magnetic flux leakage, an improvement of magnetic saturation capability, and an enhancement of working harmonics of the air-gap flux density. As a result, a significant improvement in torque capability, eddy current losses, and efficiency was obtained. Hence, the RPM-FS machine proposed in this work is capable of being used in EV and HEV applications.

Centralized control algorithm limits the hardware flexibility of a modular multilevel converter (MMC). Therefore, distributed control structure has recently started to be seen in the industry application. Even though distributed controller reduces a single point of failure risk compared to the centralized controller, the failure risk of the entire control systems increases due to the number of local controllers. However, the distributed controller can be programmed in such a way as to replace the faulty local controller and sustain the MMC operation. In this paper, the distributed modular fault-tolerant controller is implemented in a laboratory-scale MMC prototype. The controller is built to control four SMs per phase for the proof-of-concept. Therefore, the MMC prototype is also built by two SMs per arm. The controller capability is validated with experimental and the Opal-RT result-time simulator results in a control-hardware-in-loop (CHIL) environment.