Bioenergy is the form of clean energy with the greatest potential for growth in Spain, especially in those regions with a large forest area and a high potential for the utilization of forest resources for energy purposes. This is the case in Galicia (a region located in northwestern Spain), where the communal management of forest resources is widespread. Within this type of management, there is a pioneering case study in which biomass energy use activities have been initiated through an international project. The possible success of this project is of great importance since it could represent an alternative to the main energy activity in the common management of forests: the production of wind energy. In recent years, and with a special increase in 2022, Galician public opinion has expressed its opposition to the implementation of new wind farms in its forests. The aim of this article is to analyze whether or not it is profitable for forest management communities to participate in bioe... [more]

Sulla (Hedysarum coronarium L.) is a new candidate crop for biofuel production. A field trial was conducted in 2018−2020 in Pyrgos, Greece, and repeated in 2019−2021 to evaluate different row spacings and cover crops for weed management in sulla in a two-factor randomized complete block design (RCBD) with four replications. Four row spacings, namely 76-cm, 51-cm, 38-cm, and 19-cm, were assigned to the main plots. Three cover crops, namely farro wheat (Triticum turgidum subsp. dicoccum (Schrank ex Schübler) Thell.), common vetch (Vicia sativa L.), white mustard (Sinapis alba L.), and an untreated control, were assigned to the subplots. In the first year of sulla growth, weed biomass, sulla stem, and total dry matter yield (DMY) were affected by growing cycles (p-value ≤ 0.05). The 19- and 38-cm row spacings resulted in the lowest weed biomass and the highest stem and total sulla DMY in the first year of sulla growth. White mustard was the most weed-suppressive cover crop in both years a... [more]

The proliferation of unmanned aerial vehicles (UAVs) has spawned a variety of intelligent services, where efficient coordination plays a significant role in increasing the effectiveness of cooperative execution. However, due to the limited operational time and range of UAVs, achieving highly efficient coordinated actions is difficult, particularly in unknown dynamic environments. This paper proposes a multiagent deep reinforcement learning (MADRL)-based fusion-multiactor-attention-critic (F-MAAC) model for multiple UAVs’ energy-efficient cooperative navigation control. The proposed model is built on the multiactor-attention-critic (MAAC) model, which offers two significant advances. The first is the sensor fusion layer, which enables the actor network to utilize all required sensor information effectively. Next, a layer that computes the dissimilarity weights of different agents is added to compensate for the information lost through the attention layer of the MAAC model. We utilize th... [more]

Lithium-ion batteries are widely used in the electric vehicle industry due to their recyclability and long life. However, a failure of lithium-ion batteries can cause some catastrophic accidents, such as electric car battery explosion fires and so on. To prevent such harm from occurring, it is essential to monitor the remaining useful life of lithium-ion batteries and give early warning. In this paper, an adaptive noise reduction approach is proposed to predict the RUL (Remaining Useful Life) of lithium-ion batteries, which uses CEEMDAN (Complete Ensemble Empirical Mode Decomposition with Adaptive Noise) combined with wavelet decomposition to achieve adaptive noise reduction decomposition, and then inputs the obtained IMF (Intrinsic Mode Function) components into LS−RVM (Least Square Relevance Vector Machine) for training, prediction, and reconstruction, so as to achieve high-precision prediction of RUL. Moreover, in order to verify the validity of the model, the model in this paper is... [more]

The heat storage and release performance of cascade phase change units are investigated numerically for users in Inner Mongolia’s severe cold region. Three schemes of phase change material combinations are thoroughly tested. We obtained a better material combination scheme S3 (palmitic acid + polyethylene glycol), which has higher heat storage capacity per unit mass, higher average heat flux, and better unit synchronisation performance, so that it is more suitable for solar heating and cascade heat storage units in cold regions of Inner Mongolia. This study takes into account the irradiation variation of typical days during the winter heating season. The results show that the palmitic acid and polyethylene glycol combination scheme has the highest total heat storage per unit mass. This scheme also performs well in the synchronisation of two-stage storage units. When compared to the other two schemes, the average heat flux is increased by 25.5% for the first stage unit and 16.8% for the... [more]

Smart meters (SMs) can play a key role in monitoring vital aspects of different applications such as smart grids (SG), alternative currents (AC) optimal power flows, adversarial training, time series data, etc. Several practical privacy implementations of SM have been made in the literature, but more studies and testing may be able to further improve efficiency and lower implementation costs. The major objectives of cyberattacks are the loss of data privacy on SM-based SG/power grid (PG) networks and threatening human life. As a result, losing data privacy is very expensive and gradually hurts the national economy. Consequently, employing an efficient trust model against cyberattacks is strictly desired. This paper presents a research pivot for researchers who are interested in security and privacy and shade light on the importance of the SM. We highlight the involved SMs’ features in several applications. Afterward, we focus on the SMs’ vulnerabilities. Then, we consider eleven trust... [more]

In recent years, an alarming increase in CO2 emissions has been noticed [...]

Membrane desalination (MD) is preferred over other desalination techniques since it requires a lower temperature gradient. Its performance can be further enhanced by preheating the intake of saline water. In this context, a novel solar-assisted air gap membrane desalination (AGMD) system was hypothesized. The motivation was derived from the fact that the use of solar energy to provide power and a pre-heating source for the intake of saline water can offer a sustainable alternative that can further enhance the acceptance of MD systems. Since solar panels suffer from a loss of efficiency as they heat up during operation, a solar-assisted air gap membrane desalination (AGMD) system can help to improve the overall system performance by (1) providing the necessary pumping power to operate the system and (2) improving solar panel performance by exchanging heat using water that is (3) used to pre-heat the saline water necessary for increased performance of the AGMD system. To verify the hypot... [more]

State-of-charge (SOC) estimation of lithium-ion batteries (LIBs) is the basis of other state estimations. However, its accuracy can be affected by many factors, such as temperature and ageing. To handle this bottleneck issue, we here propose a joint SOC-SOH estimation method considering the influence of the temperature. It combines the Forgetting Factor Recursive Least Squares (FFRLS) algorithm, Total Least Squares (TLS) algorithm, and Unscented Kalman Filter (UKF) algorithm. First, the FFRLS algorithm is used to identify and update the parameters of the equivalent circuit model in real time under different battery ageing degrees. Then, the TLS algorithm is used to estimate the battery SOH to improve the prior estimation accuracy of SOC. Next, the SOC is calculated by the UKF algorithm, and finally, a more accurate SOH can be obtained according to the UKF-based SOC trajectory. The battery-in-the-loop experiments are utilized to verify the proposed algorithm. For the cases of temperatur... [more]

Uncontrolled inflow of formation fluid (brine) into a well adversely affects the cation−anion bonds in solutions and leads to their dissociation and loss of aggregative stability. Blow-out significantly complicates the drilling process and leads to an increase in non-productive time and in financial costs for problem solving. It is necessary to create a blocking screen that allows separation of the layer from the well and prevents brine flow. This article is devoted to the development of polymeric-blocking compositions that work due to the crystallization reaction of divalent salts of calcium and magnesium chlorides. More than 14 components were detected in the formation fluid on the atomic emission spectrometer. Based on the study of the compatibility of components with brine and the study of rheology and filtration processes through a real core under HPHT conditions, the optimal component polymer composition was selected. The reason for the increase in the rheology of composition dur... [more]

In this article the structural features of friction pairs of brakes are analyzed. Heat transfer processes with new boundary conditions are described analytically with the addition of flow conditions and the appearance of a boundary thermal layer to convective heat transfer. The joint action of heat conduction and convection fields is presented. The release of heat during friction is due to the destruction of adhesive bonds in the actual contact zones, and the stress−strain state of micro-roughnesses. It should be said that due to the presence of accompanying transfer processes, complex heat transfer is much more complex compared to purely conductive, convective, and radiative heat transfer, which significantly complicates its analytical and experimental study. In this regard, the processes of complex heat transfer are currently studied little. From the point of view of non-equilibrium thermodynamics, the main task of describing the transfer process is to establish a relationship betwee... [more]

Offshore geological sequestration of CO2 offers a viable approach for reducing greenhouse gas emissions into the atmosphere. Strategies include injection of CO2 into the deep-ocean or ocean-floor sediments, whereby depending on pressure−temperature conditions, CO2 can be trapped physically, gravitationally, or converted to CO2 hydrate. Energy-driven research continues to also advance CO2-for-CH4 replacement strategies in the gas hydrate stability zone (GHSZ), producing methane for natural gas needs while sequestering CO2. In all cases, safe storage of CO2 requires reliable monitoring of the targeted CO2 injection sites and the integrity of the repository over time, including possible leakage. Electromagnetic technologies used for oil and gas exploration, sensitive to electrical conductivity, have long been considered an optimal monitoring method, as CO2, similar to hydrocarbons, typically exhibits lower conductivity than the surrounding medium. We apply 3D controlled-source electromagn... [more]

As the main noise source in the hydrogen fuel cell system, the noise level of the centrifugal air compressor greatly affects the comfort of the hydrogen fuel cell vehicle, and can be effectively reduced by optimizing the trailing edge sweep angle of the blade. In this paper, the computational fluid dynamics model was used to study the influence of the trailing edge sweep angle on the aerodynamic performance and flow characteristics of a centrifugal air compressor for vehicle fuel cells. The Ffowcs Williams−Hawkings equation and the computational fluid dynamics−boundary element coupling method were adopted to calculate the dipole source strength on the surface of the blade and the radiated aerodynamic noise, respectively, under the different trailing edge sweep angles. The results showed that the trailing edge sweep could lead to an increase in pressure ratio as well as isentropic efficiency, and a decrease in the intensity of flow separation. Meanwhile, the sound pressure level of the... [more]

Background: Bioenergy attracts much attention due to the global demand for renewable and sustainable energy resources. Waste biomass feedstocks—date pits, coffee waste, and cow dung—require efficient and environmentally friendly waste-management technologies such as pyrolysis. Fast pyrolysis occurs at fast heating rates (10−100 °C/s), generates high bio-oil yields, and is the most widely used process for biofuel generation. The aim of the study is to compare the effect of pyrolysis between single, binary, and ternary feeds on thermal degradation behavior and bio-oil composition. Methods: Thermogravimetric analysis (TGA) was conducted at 30 °C/min from room temperature to 850 °C to understand the thermal degradation behavior of the biomasses. A Pyroprobe® reactor—a micro-scale pyrolyzer—was used to conduct the fast pyrolysis at 500 °C with a heating rate of 10 °C/s, and the volatile contents were quantified using a gas chromatograph−mass spectrometer (GC/MS). Results: The (TGA) showed t... [more]

This article is devoted to the development of technology for improving the efficiency of directional well drilling by predicting and adjusting the system of static and dynamic components of the actual weight on the bit, based on the real-time data interpretation from telemetry sensors of the bottom hole assembly (BHA). Studies of the petrophysical and geomechanical properties of rock samples were carried out. Based on fourth strength theory and the Palmgren−Miner fatigue stress theory, the mathematical model for prediction of effective distribution of mechanical specific energy, using machine learning methods while drilling, was developed. An algorithm was set for evaluation and estimation of effective destruction of rock by comparing petrophysical data in the well section and predicting the shock impulse of the bit. Based on the theory provided, it is assumed that the given shock impulse is an actual representation of an excessive energy, conveyed to BHA. This excessive energy was qua... [more]

The strategic intent of the African Union is to develop a “Smart Integrated African Electric Power Super Grid” driven by modern tools and advances in high-voltage direct current (HVDC) engineering and flexible alternating current technology systems (FACTS), which is central in supporting Africa’s sustained economic growth and development. The southern African region, including South Africa, is beset by the critical challenges of perennial load-shedding, which impedes economic growth and aggravates unemployment. This has led to the insecurity of electricity supplies and degraded the quality of life. The parallel operation of high-voltage direct current (HVDC) and flexible AC technology systems (FACTS) controllers is gaining traction as system conditions become more complex, such as weak power networks which requires increased stability requirements, resulting in load-shedding and power outages. These adversely affect business productivity and adversely affect GDP and economic growth. Th... [more]

As the energy demand increases due to the developing electric power industry, the fault current becomes higher during the fault time. A new approach is needed to reduce a fault current in a power distribution system, since the fault currents influence other protective devices’ operation. To decrease the fault current, the superconducting fault current limiter (SFCL) has been suggested. The SFCL has no power loss with no effect on a power distribution system because the SFCL impedance only occurs during the fault time. However, the SFCL can reduce the fault current; it causes the trip time delay of the over current relay (OCR). Compensation methods for the balanced fault have been invented in previous studies, while research on unbalanced ground fault compensation are few. In this paper, the compensation method configured with impedance components of a power distribution system is introduced to eliminate the influence of the SFCL on the OCR. In addition, the components of the SFCL imped... [more]

An energy transition is in progress around the globe, notably led by an increase in the deployment of renewable energy and a shift toward less emissions-intense options, notably in the transportation sector. This research investigates the potential role that new transportation options, namely flying vehicles, may play toward progressing the energy transition. As flying vehicles are a relatively new technology yet to penetrate the market, it is also prudent to consider the ethical, legal, and social issues (ELSI) associated with their implementation, alongside the potential energy and environmental impacts. Through a review of ELSI and energy and environmental literature, we identify research gaps and identify how flying vehicles may impact upon the energy transition over time. Our research identifies several critical aspects of both ELSI and energy and environmental academia relevant to the future deployment of flying vehicles and describes a deployment timeline and the resultant socie... [more]

As a new passive cooling technology, space radiation cooling has great potential for development because the cooling itself has no energy consumption, and the radiation heat exchanger does not affect the appearance, with low noise and low cost. Several rectangular stainless steel plates coated with RLHY-2 material are used as the transmitter for the field test. The experimental results show that, in the case of no windscreen, the increase of outdoor humidity will reduce the cooling effect, and the greater the humidity, the more pronounced the reduction effect. Significantly when the humidity increases from 78% to 90%, the cooling power of the cooler reduces from 102 to 67 W/m2. The thickness of the cloud layer also affects the cooling effect of the space radiative cooler. Compared with the clear weather, the cooling power of the cooler is reduced by 11.65 W/m2 on average under foggy weather conditions. Compared with the force-1 wind and the force-3 wind, the cooling effect of the coole... [more]

Numerical simulation of polypropylene laminated paper insulation is a serious challenge, as it must take into account the layered structure and presence of longitudinal and radial gaps in the coils of the winded tape for cables with sector-shape conductive cores. Thus far, it has been performed only with serious simplifications. We propose a technique for numerical modeling of electric parameters in this type of insulation by reducing a complex 3D problem to a simplified 2D model that takes into account the main influencing factors. The results of modeling the distribution of electric field strength and current density in insulation are presented, and the influence of the location of gaps between the edges of winded tape on the conductivity of cable insulation is estimated. Analytical expressions are obtained for estimating the electrical resistance of insulation while taking into account the parameters of the butt gap between the insulating tapes. The results of calculations, numerica... [more]

To achieve the goals of low carbon emission and carbon neutrality, some urgent challenges include the development and utilization of low-carbon or zero-carbon internal combustion engine fuels. Hydrogen, as a clean, efficient, and sustainable fuel, has the potential to meet the abovementioned challenges. Thereby, hydrogen internal combustion engines have been attracting attention because of their zero carbon emissions, high thermal efficiency, high reliability, and low cost. In this paper, the opportunities and challenges faced by hydrogen internal-combustion engines were analyzed. The progress of hydrogen internal-combustion engines on the mixture formation, combustion mode, emission reduction, knock formation mechanism, and knock suppression measures were summarized. Moreover, possible technical measures for hydrogen internal-combustion engines to achieve higher efficiency and lower emissions were suggested.

Green hydrogen—a carbon-free renewable fuel—has the capability to decarbonise a variety of sectors. The generation of green hydrogen is currently restricted to water electrolysers. The use of freshwater resources and critical raw materials, however, limits their use. Alternative water splitting methods for green hydrogen generation via photocatalysis and photoelectrocatalysis (PEC) have been explored in the past few decades; however, their commercial potential still remains unexploited due to the high hydrogen generation costs. Novel PEC-based simultaneous generation of green hydrogen and wastewater treatment/high-value product production is therefore seen as an alternative to conventional water splitting. Interestingly, the organic/inorganic pollutants in wastewater and biomass favourably act as electron donors and facilitate the dual-functional process of recovering green hydrogen while oxidising the organic matter. The generation of green hydrogen through the dual-functional PEC pro... [more]

The aim of this study was to present factors shaping biodiesel production in Poland influenced by the Common Agricultural Policy (CAP) of the European Union (EU). The performance of Polish biodiesel producers was analyzed. A regression model was built to identify the factors that impacted biodiesel production in Poland. The Farm Accountancy Data Network (FADN) was the main source of information about Polish biodiesel farmers. The FADN is the most comprehensive and detailed source of economic and agricultural data in Poland. Changes in the number of biodiesel producers in the Polish market were analyzed with the use of indicators. In the last stage of the study, the impact of selected variables on the performance of rapeseed farms was determined in a regression analysis. The second source of information was Eurostat data, which provided information about pure biodiesel production in the European Union (EU) countries from 2004 to 2019. The biggest producers of pure biodiesel in the Europ... [more]

This review aims to highlight the current advances in hybrid redox flow battery (HRFB) technology, encompassing one of the best combinations of efficiency, cost and flexibility due to its module construction, which offers independent scaling of power density and energy capacity. This work emphasizes the interest of the scientific community both in (i) studying the properties and principles of HRFB operation in order to improve commonly proposed systems, and in (ii) the development of energy storage devices with new reagent types or RFB concepts. The data provided enhances the reader to conclude whether novel concepts in halogen oxidizers utilization could help to overcome the problem of insufficient power and energy densities of common RFB.

Industrial power plant buildings differ from all other types of buildings, mainly due to their significant heights and volumes without internal floor sections, exceptionally heat gains during daily work, and potentially high fire risk. Those buildings consist of boiler and turbine houses with multilevel stairways. This complicated architecture creates an extraordinary natural thermal stack effect, causing special ventilation and smoke control systems requirements, adapted to their specific structures and internal conditions. The paper demonstrates a proposal for optimal thermal smoke control ventilation solutions in industrial power plant buildings designated on the basis of performance-based calculations and confirmed by CFD simulations. It demonstrates the possibilities of using daily ventilation in the boiler houses in a function of smoke control systems in the event of a fire and defines fundamental rules for designing the system. Additionally, a new method of sufficient staircase... [more]