The paper aims at establishing an associative link between supervisory board members’ independence and the dynamics of environmental policy transformations in the energy sector. To that end, we apply static panel models and binary logistic regression analysis to an international sample of 358 energy companies observed over the period between 1990 and 2020. Our empirical results point to a lack of any persistent link between board independence and energy transition after controlling for country-specific effects and firm-level financials. Although firms with a higher percentage of independent directors on boards are more likely to set emission targets and implement resource reduction policies, they are simultaneously more likely to be involved in environmental controversies and increase coal output. They are also significantly less likely to enforce an energy efficiency policy. No significant link is found between board independence and environmental expenditures, CO2 equivalent emission... [more]

This paper presents a scientific development aimed at improving the efficiency of turbomachines through the joint use of rotary-vane and vortex workflows. In the well-known Euler turbine, the rotor flow channels represent a set of curved pipes. The authors propose to consider in more detail the possibilities of using such rotating pipes in the implementation of an ejection (vortex) workflow. A hybrid pump was considered with the conclusion that its workflow can be described using two Euler equations. The results of computer simulation indicate that hybrid turbomachines are promising. The use of additive technology allowed the creation of micromodels of the Euler turbine with various rotor designs. Laboratory hydraulic tests showed that the liquid inlet to the rotor is possible in pulse mode. Laboratory tests of micromodels using compressed air showed that gas (or liquid) motion through curved pipes could be carried out from the rotor periphery to its center and then back, albeit throug... [more]

The recent and continuous improvement in the transportation field provides several different opportunities for enhancing safety and comfort in passenger vehicles. In this context, Adaptive Cruise Control (ACC) might provide additional benefits, including smoothness of the traffic flow and collision avoidance. In addition, Vehicle-to-Vehicle (V2V) communication may be exploited in the car-following model to obtain further improvements in safety and comfort by guaranteeing fast response to critical events. In this paper, firstly an Adaptive Model Predictive Control was developed for managing the Cooperative ACC scenario of two vehicles; as a second step, the safety analysis during a cut-in maneuver was performed, extending the platooning vehicles’ number to four. The effectiveness of the proposed methodology was assessed for in different driving scenarios such as diverse cruising speeds, steep accelerations, and aggressive decelerations. Moreover, the controller was validated by consider... [more]

A non-isolated buck converter, together with resonance and zero voltage transition to achieve zero voltage switching (ZVS) and zero current switching (ZCS), is presented herein to upgrade the conversion efficiency. In this circuit, the main switch and the auxiliary switch are connected to the common ground so as to make the two switches easily driven. Furthermore, these two switches take time division multiplexing operation. In addition, the pulse width modulation (PWM) control technique is utilized so as to render the output inductor and capacitor easily designed. In this paper, the theoretical derivation is first introduced, and secondly, some experimental results are provided to demonstrate the effectiveness of the proposed topology.

Power systems may encounter disturbances during operation as a result of switching of various components, etc. Such perturbations include transformer tap-changing action, load variations, and line outages due to various types of faults of which an earth fault is the most common. Stability analysis of a transmission system is necessary for us to determine the stability state of the system so that appropriate control measures can be implemented to guarantee system stability. This article presents the use of eigenvalue obtained from the system-linearized eigenvectors to analyze the stability state of the system. The choice of the eigenvalue principle is based on the strength of accuracy of the method to determine the actual state of the system providing adequate data for easy solution to the problem. The node admittance parameters computed from the line parameters is applied to the eigenvalue−eigenvector model to determine the system stability state. The state of the eigenvalue is used as... [more]

Automotive airbags protect occupants from crash forces during severe vehicle collisions. They absorb energy and restrain the occupants by providing a soft cushion effect known as the restraint effect. Modern airbags offer partial restraint effect control by controlling the bag’s vent holes and providing multi-stage deployment. Full restraint effect control is still a challenge because the closed-loop restraint control system needs airbag−occupant contact and interaction feedback. In this work, we have developed novel single and matrix capacitive tactile sensors to measure the occupant’s contact data. They can be integrated with the airbag surface and folded to follow the dynamic airbag shape during the deployment. The sensors are tested under a low-velocity pendulum impact and benchmarked with high-speed test videos. The results reveal that the single sensor can successfully measure occupant−airbag contact time and estimate the area, while the contact position is additionally identifie... [more]

Currently, global warming has been a serious issue, which is closely related to anthropogenic emission of Greenhouse Gas (GHG) in the atmosphere, particularly Carbon Dioxide (CO2). To help achieve carbon neutrality by decreasing CO2 emissions, Oxy-Fuel Combustion (OFC) technology is becoming a hot topic in recent years. However, few findings have been reported about the implementation of OFC in dual-injection Spark Ignition (SI) engines. This work numerically explores the effects of Water Injection (WI) strategies on OFC characteristics in a practical dual-injection engine, including GDI (only using GDI), P50-G50 (50% PFI and 50% GDI) and PFI (only using PFI). The findings will help build a conceptual and theoretical foundation for the implementation of OFC technology in dual-injection SI engines, as well as exploring a solution to increase engine efficiency. The results show that compared to Conventional Air Combustion (CAC), there is a significant increase in BSFC under OFC. Ignition... [more]

This paper develops a novel hybrid feature learner and classifier for vibration-based fault detection and isolation (FDI) of industrial apartments. The trained model extracts high-level discriminative features from vibration signals and predicts equipment state. Against the limitations of traditional machine learning (ML)-based classifiers, the convolutional neural network (CNN) and deep neural network (DNN) are not only superior for real-time applications, but they also come with other benefits including ease-of-use, automated feature learning, and higher predictive accuracies. This study proposes a hybrid DNN and one-dimensional CNN diagnostics model (D-dCNN) which automatically extracts high-level discriminative features from vibration signals for FDI. Via Softmax averaging at the output layer, the model mitigates the limitations of the standalone classifiers. A diagnostic case study demonstrates the efficiency of the model with a significant accuracy of 92% (F1 score) and extensive... [more]

The capacitive and kinetic parameters of hydride electrodes obtained on the basis of single-phase LaNi5-xGe alloys (x = 0.3 and 0.6) were related to their corrosive properties. The content of the article is important from the point of view of the improvement of LaNi5 type materials for hydrogen energy storage used as anodes in NiMH batteries. The presence of large amounts of germanium (10% at.) in the alloy results in much less surface degradation compared to the low-germanium alloy (5% at.), which, on the one hand, leads to an improvement in the resistance of the high-germanium LaNi4.4Ge0.6 alloy to long-term cycling, but on the other hand, contributes to lower hydrogen absorption by this material. The maximum discharge capacity of 293 mAh g−1 was obtained for the low-germanium alloy using a charge/discharge current density of 185 mA g−1. The studied electrode also shows a lower tendency to self-discharge and a clearly higher exchange current density.

Photovoltaic systems can strengthen the energy matrix aiming at energy sustainability, however, their intermittence, the availability time frame and seasonality effects are complicating aspects for the operation of these systems. To mitigate such problems, a possible measure is the operation of hybrid systems (HS) associated with storage systems to meet the energy demand. This study presents real operational scenarios for the management of a hybrid mini-grid installed in the Amazon region in Brazil, capable of managing energy supply and demand, changing the generation curve, reducing fossil fuel consumption and energy costs, in addition to providing flexibility and operational safety to the electrical operating under on-grid or off-grid conditions. Through technical and economic analyses, the objective of this study is to show that hybrid systems can be implemented in small and medium consumers, in addition to generating a new market option for utilities. This research evaluates the op... [more]

With the intensification of human activities, a large amount of oil and organic solvent waste has been created, resulting in serious ecological and environmental pollution. Therefore, how to balance environmental benefits and economic benefits control a large number of organic solvent and oil pollution is an urgent problem. To solve this problem, a highly efficient oil-water separation material was designed and prepared in this paper. Graphene oxide aerogels were synthesized by the Pickering emulsion and hydrothermal method, and then hydrophobically lipophilic polydimethylsiloxane (PDMS) reduced graphene oxide aerogel composites (PDMS/GA) were obtained by modification of PDMS. The surface functional groups, hydrophobicity, thermal stability, and micromorphology of the materials were tested by various characterization methods. Their properties were tested by an oil absorption test and repeated experiments. The oil absorption performance experiments and repeated performance experiments o... [more]

Pores of shale exhibit multiscale characteristics, and pore characterization is challenging due to the complexity of pore systems. Currently, research is focused on nano-submicron pores, but the structure of micrometer-scaled pores is not well understood. In this research, an investigation of the three-dimensional pore network of the Chang 7 shale in the Ordos Basin of China was conducted, in order to provide an insight into the full characteristics of pore systems. Nano-CT and micro-CT scanning technology was used to comprehensively delineate the pore structure at different scales, for further understanding the gas storage mechanism in shale rocks. Results show that the radius of micro-scale pores ranges from 1 to 15 μm, with an average of 2.8 μm, and pores with radii of 1−5 μm occupy approximately 90% of all the pores. For the nano-scale pores, the size ranges from 86 to 2679 nm, with an average of 152 nm, yet it has a rather concentrated distribution within 300 nm. The nano-scale po... [more]

This paper aims to investigate the impact of space weather on China’s electricity market. Based on data products provided by NOAA and the National Energy Administration in China, this paper uses solar wind velocity as a solar weather indicator and the disturbance storm time index as a magnetospheric weather indicator to match monthly Chinese electricity market data over 10 years. Based on a VAR model, we found that (1) space weather increases the demand for electricity in China, and solar wind speed and the geomagnetic index increase the electricity consumption of the whole of Chinese society, as space weather mainly increases the electricity consumption of the secondary and industrial sectors. (2) The geomagnetic index significantly promotes power station revenue. (3) Space weather is associated with increased energy consumption. The geomagnetic index significantly increases the coal consumption rate of fossil power plants in China, but the solar wind speed has nothing to do with the... [more]

Three-phase three-level unidirectional rectifiers are among the most adopted topologies for general active rectification, achieving an excellent compromise between cost, complexity and overall performance. The unidirectional nature of these rectifiers negatively affects their operation, e.g., distorting the input currents around the zero-crossings, limiting the maximum converter-side displacement power factor, reducing the split DC-link mid-point current capability and limiting the converter ability to compensate the low-frequency DC-link mid-point voltage oscillation. In particular, the rectifier operation under non-unity power factor and/or under constant zero-sequence voltage injection (i.e., when unbalanced split DC-link loading occurs) typically yields large and uncontrolled input current distortion, effectively limiting the acceptable operating region of the converter. Although high bandwidth current control loops and enhanced phase current sampling strategies may improve the rec... [more]

A molten salt reactor (MSR) has unique safety and economic advantages due to the liquid fluoride salt adopted as the reactor fuel and heat carrier fluid. The operation scheme and control strategy of the MSR plant are significantly different from those of traditional solid-fuel reactors because of the delayed neutron precursors drift with the liquid-fuel flow. In this paper, a simulation platform of the MSR plant is developed to study the control characteristics under normal and accident conditions. A nonlinear dynamic model of the whole system is built in the platform consisting of a liquid-fuel reactor with a graphite moderator, an intermediate heat exchanger and a steam generator. A new control strategy is presented based on a feed-forward and feedback combined scheme, a power control system and a steam temperature control system are designed to regulate load changes of the plant. Three different types of operation conditions are simulated with the control systems, including transien... [more]

This work describes the design, construction and testing of a thermo-electric conditioning device installed in a neonatal incubator with the aim of improving the precision in the regulation of the interior air temperature, reducing noise and interior vibration, and improving the life of the neonate. A simplified one-dimensional thermal model has been developed, made up of resistances and thermal capacities that simulate the thermal behaviour of all the elements of the system from end to end. All the equations of the model are obtained in a nodal way, allowing the mathematical relationship between the input and output to be known. This model makes it possible to improve temperature control, avoiding the deviations that occur in the traditional model controlled by sensors at both ends. The computational model allows to predict the variation of temperatures in transient and permanent regime. This model allows the design and sizing of the thermoelectric system for different outdoor environ... [more]

A small-scale organic Rankine cycle (ORC) with kW-class power output has a wide application prospect in industrial low-grade energy utilization. Increasing the expansion pressure ratio of small-scale ORC is an effective approach to improve the energy efficiency. However, there is a lack of suitable expander for small-scale ORC that can operate with a high efficiency under the condition of large expansion pressure ratio and small mass flow rate. Aiming at the design of high-efficiency axial-flow turbine in small ORC system, this paper investigates the performance of a kW-class axial-flow turbine and proposes a method for efficiency improvement. First, the preliminary design of an axial-flow turbine is conducted to optimize the geometric parameters and aerodynamic parameters. Then, the effects of tip clearance and trailing edge thickness on turbine performance are analyzed under design and off-design conditions. The results show that the efficiency of the two-stage or three-stage turbine... [more]

High-order filters, such as LCL, are more commonly employed in grid-connected inverters (GcIs) as an interference element for the better attenuation of switching harmonics. However, LCL filters may have resonance poles and antiresonance zeros in the frequency response with inverter side current. This may affect the stability of the system and limit the control bandwidth with the simple single-loop PI control. This becomes severe with the introduction of grid impedance due to the large distance between renewable energy sources and the power grid. To mitigate this effect, active damping and sensorless damping is preferred with pre-information about grid impedance. In this paper, linear active disturbance rejection control (ADRC) is introduced, first to L filter type GcI and later extended to LCL filter type GcIs with minimum modification. From the frequency analysis, it is shown that the characteristics of the proposed control scheme remain the same even with a change in filter order and... [more]

Hybrid vehicles are now more common in response to increasing global warming. The hybridization of energy sources and energy storage units enables improving the sustainability, reliability, and robustness of power systems. To reach the objective of zero emissions, a proton exchange membrane hydrogen fuel-cell was utilized as an energy source. The aim of this research was to create an accurate optimal sizing procedure for determining the nominal rating of the necessary sources. We modeled the fuel cell and the battery pack using data from real experimental results to create the generic database. Then, we added data on the mission profile, system constraints, and the minimization target function. The mission profile was then analyzed by the sizing algorithm to determine optional minimum and maximum fuel cell ratings. Analyzing the optional solutions using the vehicle real time energy management system controller resulted in a set of solutions for each available rated fuel cell, and the o... [more]

The three-dimensional tubular heat exchanger has excellent performance in single-phase flow, but its performance in gas solid two-phase flow is still lacking research. In this paper, analysis and comparison of heat exchanger prototypes made up of four different three-dimensional tubes by different comprehensive performance evaluation methods are carried out through experimental research and theoretical analysis. The research results show that the ratio of the long axis to the short axis of the three-dimensional tube has an important influence on its heat transfer performance and flow resistance. Furthermore, a reasonable ratio can be obtained by comparing its comprehensive performance. Among the comprehensive performance analysis results of four kinds of three-dimensional tubes, the comprehensive performance factor ηo-I of type I is the best which achieves the purpose of heat transfer enhancement. Results from the current research could provide beneficial guidance for further design an... [more]

The era of Industry 4.0 is characterized by the use of new telecommunications ICT technologies and networking of the economy. This results in changes both in the way businesses operate and in customer expectations of products offered on the market. The use of modern ICT technologies has made it possible to create cyber-physical systems based on intelligent machines and devices that communicate with each other in real time and allow the integration of resources from different companies to carry out joint production projects. Today’s consumer expects products tailored to their needs and expectations. These expectations can be met by leveraging the potential of highly specialized manufacturing service companies centered around e-business platforms. The article presents the results of research using bibliometric analysis and the results of surveys conducted among small and medium-sized enterprises. The concept of e-business platforms supporting rapid prototyping of temporary networks of co... [more]

The paper aims to identify and explain the factors influencing the decision-making process on the behavioural intention to use home photovoltaic systems by Polish households and potential buyers. The survey was conducted in 2021 on a sample of 521 participants. The research used a random sample of households without PV systems located in the rural areas in Poland, where the adoption of innovative technologies related to obtaining energy from renewable sources is especially important. Structural equation modelling (SEM) was applied to measure structural relationships. The main finding indicates that consumer innovativeness has the strongest impact on the intention to purchase a photovoltaic installation. The perceived value also affects the intention to purchase a photovoltaic installation. The perceived value is affected by perceived economic benefits and indirectly by the subjective knowledge of PV. Surprisingly, environmental concerns negatively affect the intention to use PV install... [more]

During wireless charging, the transmission distance of electric vehicles varies, resulting in different levels of electromagnetic field leakage. An improved active shielding technology, the double-coil dynamic shielding technology, is proposed in this paper for wireless power transfer (WPT) systems with different transmission distances. Modeling, simulation, and experiments are performed for the WPT system with a double-coil dynamic shielding scheme and compared with other cases. The results show that the proposed double-coil dynamic shielding scheme is able to shield approximately 70% of the electromagnetic field leakage for WPT systems at different transmission distances. In addition, it essentially causes no degradation in transmission efficiency (only 3.1%). The effectiveness and feasibility of the proposed scheme are verified.

This paper deals with the HEV real-time energy management problem using deep reinforcement learning with connected technologies such as Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I). In the HEV energy management problem, it is important to run the engine efficiently in order to minimize its total energy cost. This research proposes a policy model that takes into account road congestion and aims to learn the optimal system mode selection and power distribution when considering the far future by policy-based reinforcement learning. In the simulation, a traffic environment is generated in a virtual space by IPG CarMaker and a HEV model is prepared in MATLAB/Simulink to calculate the energy cost while driving on the road environment. The simulation validation shows the versatility of the proposed method for the test data, and in addition, it shows that considering road congestion reduces the total cost and improves the learning speed. Furthermore, we compare the proposed met... [more]

After the awareness-raising of recent years for coping with the global societal, economic and environmental challenges, the need for sustainable planning in the transport sector has become even more evident. Initiatives aiming at promoting sustainable and innovative mobility solutions, especially in urban areas where mobility needs are higher and transport problems are more intense, have been launched by different organizations around the world. In this context, autonomous electric vehicles are emerging as a promising solution; however, they are accompanied by new infrastructure requirements, along with safety concerns. Policymakers will be confronted with an array of choices, such as plug-in or wireless, dynamic or stationary charging and mixed flow with conventional vehicles or dedicated lanes, taking into account the uncertain impacts of innovation on safety and sustainability. Within this scope, these infrastructure alternatives are evaluated and prioritized, for the first time, in... [more]