Recently, as the use of wearable devices and the demand for eco-friendly energy have increased, many studies have been conducted on triboelectric nanogenerators (TENGs), which can economically harvest energy. Paper is considered a promising substrate and frame material that can be used to manufacture self-powered TENGs, owing to its flexibility, low cost, and accessibility. Herein, we present a sandwich-structured foldable paper-based TENG (FP-TENG) that comprises flexible materials and uses paper as a substrate. The FP-TENG can generate up to 572 mW/m2 of power via contact−separation of the triboelectric electrified body at the top and bottom. With more folds of the FP-TENG, the triboelectric cross-sectional area increases, and, thus, the electrical output increases. In addition, the proposed TENG exhibits excellent durability without signal degradation under 5000 cycles of repeated pushing motions. To demonstrate its practicality, the FP-TENG was manufactured in the form of a wristwa... [more]

The electrification of vehicles from the automotive and public transport industries can reduce harmful emissions if implemented correctly, but there is little evidence of whether the electrification of heavy freight transportation vehicles (HFTVs), such as multi-articulated vehicles, used in the freight industry could see the same benefits. This work studied heavy multi-articulated freight vehicles and developed a comparative analysis between electric and conventional diesel power trains to reduce their total emissions. Real-world drive cycle data were obtained from a heavy multi-articulated freight vehicle operating around Melbourne, Australia, with a gross combination mass (GCM) of up to 66,000 kg. Numerical models of the case study freight vehicle were then simulated with diesel, through-the-road parallel (TTRP) hybrid and electric power trains over the five different drive cycles with fuel and energy consumption results quantified. Battery weights were added on top of the real-worl... [more]

The Jianghan Basin is a lacustrine basin in central China developing multiple salt bearing deposits in the Eocene with the success of shale oil exploration in the Qianjiang Formation. The lower member of the Xingouzui Formation in the Chentuokou Depression has become another exploration target. However, rapid changes in lithofacies and strong sedimentary heterogeneity limit the exploration progress. This study aimed to explore the sequence division, lithofacies characteristics, and sedimentary environment using sedimentological, X-ray fluorescence (XRF) and X-ray diffraction (XRD) analyses. The sequence stratigraphic analysis indicates that the low member of the Xingouzui Formation is divided into two third-order sequences, namely SQ1 and SQ2, and four system tracts, including highstand systems tract (HST), lake expanding system tract (EST), early highstand system tract (EHST), and late highstand system tract (LHST). Moreover, a total of nine major lithofacies and five lithofacies asso... [more]

The huge number of electronic devices called the Internet of Things requires miniaturized, autonomous and ecologically sustainable power sources. A viable way to power these devices is by converting mechanical energy into electrical through electro-active materials. The most promising and widely used electro-active materials for mechanical energy harvesting are piezoelectric materials, where the main one used are toxic or not biocompatible. In this work, we focus our attention on biocompatible and sustainable piezoelectric materials for energy harvesting. The aim of this work is to facilitate and expedite the effort of selecting the best piezoelectric material for a specific mechanical energy harvesting application by comprehensively reviewing and presenting the latest progress in the field. We also identify and discuss the characteristic property of each material for each class to which the material belong to, in terms of piezoelectric constants and achievable power.

This work aims to investigate the influence of temperature and chemical impregnation in the textural and morphological composition of the bio-adsorbent of bio-adsorption via thermal cracking of the seeds of açaí. The experiments were carried out at 400 °C and 450 °C using a pilot scale reactor. The efficiency of the organic process was calculated in terms of liquid and solid products selected with a chemical impregnation process with NaOH, mainly with the liquid that had a greater product conversion. The elementary samples of the solid products occur with the occurrence of carbonization with an increase in the temperature of the process and the presence of impregnation. The textural and morphological characterization occurred with an analysis of FT-IR, SEM/EDS, XRF, and B.E.T. The in-phase product was developed through the creation of açaí seed in nature and impregnated with NaOH solution (2 M) at temperatures of 400 °C and 450 °C. The adsorption kinetics of acetic acid were investigat... [more]

Solar-powered adsorption chillers are a particularly interesting alternative to energy-intensive conventional refrigeration systems. Integration of the adsorption chiller with solar collectors is a very promising concept since the increase in solar radiation coincides with the increased demand for cooling. Such a solution is very economical and environmentally friendly. It also fits in with current trends related to energy policy and sustainable development. The article presents the results of tests conducted for a two-bed adsorption chiller integrated with solar collectors. The tests were performed on selected days of the summer period (July and August) at the KEZO Research Centre PAS in Jablonna (Poland). Based on the results obtained, the performance parameters of the adsorption chiller were determined, and the problems associated with the integration of all components of the system were identified and discussed. The values of the determined Coefficient of Performance (COP) and cool... [more]

As a chemical absorption method, the new ammonia carbon capture technology can capture CO2. Adding ethanol to ammonia can reduce the escape of ammonia to a certain extent and increase the absorption rate of CO2. The dissolution and crystallization of ethanol can realize the crystallization of ammonium bicarbonate and generate solid products. The induction of the crystallization process is influenced by many parameters, such as solution temperature, supersaturation, and solvating precipitant content. The basic nucleation theory is related to the critical size of nucleation. Accurate measurement of the induction period and investigating relevant factors can help to assess the nucleation kinetics. The effects of solubilizer content, temperature, and magnetic field on the induction period of the crystallization process of ammonium bicarbonate in the ethanol−H2O binary solvent mixture and determining the growth mechanism of the crystal surface by solid−liquid surface tension and surface ent... [more]

Energy storage makes energy continuously available, programmable, and at power levels different from the original intensity. This study investigates the feasibility of compressed-air energy storage (CAES) systems on a small scale. In addition to the CAES systems, there are two TES (thermal energy storage) systems for the recovery of calories and frigories. The micro-CAES + TES system is designed for a single-family residential building equipped with a photovoltaic system with a nominal power of 3 kW. The system is optimized as a potential alternative to battery storage for a typical domestic photovoltaic system. The multi-objective optimization analysis is carried out with the modeFRONTIER software. Once the best configuration of the micro-CAES + TES system is identified, it is compared with electrochemical storage systems, considering costs, durability, and performance. The efficiency of CAES (8.4%) is almost one-tenth of the efficiency of the most efficient batteries on the market (7... [more]

The organic Rankine cycles (ORCs) have been used to convert low-enthalpy geothermal brine into power. Parameter optimization and working fluid selection are the main approaches to enhance geothermal ORC performance. This work uses environmentally friendly fluids, including R1224yd(Z), R1233zd(E), R1336mzz(Z), R601 and R601a, as the geothermal ORC working fluids. The evaporation temperatures of the selected fluids were optimized to maximize the cycle net power outputs. The thermodynamic characteristics are investigated with the consideration of the influence of the allowed reinjection temperature (ARIT). Among the selected fluids, R1224yd(Z) has the highest optimal evaporation temperature with the maximum turbine power output for a brine inlet temperature (BIT) higher than 120 °C, especially at a lower allowed reinjection temperature. However, the parasitic power consumption by the pumps in an ORC with R1224yd(Z) is also higher than with the other four fluids. The net power output for O... [more]

Aiming at the problem of large vibration of a high-subside stator inner cavity curve vane pump, the force analysis of the vane at the transition curve is carried out, and the functional relationship between the vane turning angle θ, the large arc radius R, the small arc radius r and the sliding friction is established. The particle swarm algorithm is used to optimize the solution of the objective function, and the optimized parameter values are brought into the MATLAB simulation program to obtain the optimized stator curve profile diagram. The dynamic performance of the vane pump before and after optimization is simulated using ADAMS. The results show that: the acceleration of the vane pump slide is significantly reduced; the friction between the slide and the slide groove is significantly reduced; the contact force between the slide and the stator is significantly reduced; the impact vibration of the optimized vane pump is significantly reduced; and the dynamic performance of the vane... [more]

This work aims to develop a mathematical model for the simulation of a fuel cell (FC) hybrid powertrain. The work starts from modeling a single cell to obtain information on the entire FC stack. The model obtained was integrated into a simulation tool presented in the literature that simulates the longitudinal dynamics of auxiliary power unit hybrid electric vehicles and fully electric vehicles. Therefore, the integrated model allows the simulation of hybrid vehicles equipped with FC and a battery pack that acts as a peak power source. The tool simulates the mechanical and electrical behavior of the vehicle, introducing an investigation of the power flows relating to the FC and batteries. An appropriate power split logic has been implemented, allowing the correct management of the power distribution between the FC and the batteries. The importance of analyzing FC vehicles’ behavior arises from the recent necessity to find alternative propulsion systems, overcoming the range problems as... [more]

Although aviation is considered the safest mode of transportation, the annual number of pilots blinded by laser light cannot be understated. An analysis of the available statistics indicates that it is a widespread phenomenon. The stories told by the pilots show the consequences of these incidents, ranging from temporary sight loss to months of vision problems. The article also describes the current penalties for dazzling a pilot by laser light. Moreover, limited research has been conducted on the intensity of laser light of different wavelengths passing through the fairing and through standard glasses used by pilots. Understanding the effects of laser glare on pilots can help reduce adverse events and improve the ability of safety managers to develop safety procedures. Correctly designed transport systems enable effective route planning and order processing. Methods: Two types of easily available laser pointers, drawn at different distances from the aircraft, were analyzed and the int... [more]

The aim of the present research is to assess the scale of the impact of air pollution on the level of burdening EU economies with the consequences of chronic diseases (non-communicable diseases—NCDs) in the context of limiting the potential productivity of human resources. This study attempts to identify inequalities in this area that occur in the territory of the European Union. The scale of the impact of environmental factors, and air pollution in particular, on the level of health limitations in the labor resources of EU countries was measured by the number of the years of healthy life lost (YLL and YLD) as a result of chronic diseases. The verification of the assumption of a persistently high level of dispersion was based on an analysis of the convergence process (β and σ) in the group of EU countries in 1990−2019. The results demonstrate that the level of health restrictions caused by air pollution is diverse in the group of EU-27 countries. The inequalities observed concern, in p... [more]

This article presents different phase shifting transformers (PSTs) types and their influence on the transmitted active power and energy parameters. Typical PSTs, both symmetrical (SPST) and asymmetrical (APST), are compared to the asymmetrical controllable PST (ACPST). The ACPST allows for regulating both quadrature and longitudinal voltage, which makes this type interesting in practical applications and power flow optimizations. The collected data enable a direct comparison of these PSTs’ properties. APST allows high power transfer, but the voltage increase in some cases cannot be acceptable. SPST type in taken tests has the best properties concerning the transferred power, output voltage, and internal voltage drop. ACPST, in its primary mode, can be efficiently used as a substitute for the SPST. However, in some range of injected quadrature voltages, it can achieve even better properties than the SPST. The laboratory and simulation tests allow the development of the ACPST regulation... [more]

A load frequency controller (LFC) is a crucial part in the distribution of a power system network (PSN) to restore its frequency response when the load demand is changed rapidly. In this paper, an artificial neural network (ANN) technique is utilised to design the optimal LFC. However, the training of the optimal ANN model for a multi-area PSN is a major challenge due to its variations in the load demand. To address this challenge, a particle swarm optimization is used to distribute the nodes of a hidden layer and to optimise the initial neurons of the ANN model, resulting in obtaining the lower mean square error of the ANN model. Hence, the mean square error and the number of epochs of the ANN model are minimised to about 9.3886 × 10−8 and 25, respectively. To assess this proposal, a MATLAB/Simulink model of the PSN is developed for the single-area PSN and multi-area PSN. The results show that the LFC based on the optimal ANN is more effective for adjusting the frequency level and imp... [more]

Grid integration of renewable resources such as solar and wind energy can significantly raise the level of uncertainty in power systems, making the scheduled operation of generating units difficult. Therefore, the importance of operating reserves is more emphasized to prevent disruption by sudden changes in outputs of generators. In this paper, a stochastic unit commitment (UC) model to reflect uncertainty due to a large amount of renewable resources is proposed, in which upward and downward operating reserves are deployed simultaneously, and feasibility of the reserves is examined to make the deployed reserves supplied reliably. Uncertain parameters considered in the model are wind power availability, solar direct normal irradiance, and electric load. Two-stage stochastic programming is applied to the mathematical formulation, where UC decisions including dispatch are modeled as non-anticipative variables at the first stage, and redispatch decisions to serve realized electric demand a... [more]

Improving thermal efficiency and reducing carbon emissions are the permanent themes for internal combustion (IC) engines. In the past decades, various advanced strategies have been proposed to achieve higher efficiency and cleaner combustion with the increasingly stringent fuel economy and emission regulations. This article reviews the recent progress in the improvement of thermal efficiency of IC engines and provides a comprehensive summary of the latest research on thermal efficiency from aspects of thermodynamic cycles, gas exchange systems, advanced combustion strategies, and thermal and energy management. Meanwhile, the remaining challenges in different modules are also discussed. It shows that with the development of advanced technologies, it is highly positive to achieve 55% and even over 60% in effective thermal efficiency for IC engines. However, different technologies such as hybrid thermal cycles, variable intake systems, extreme condition combustion (manifesting low tempera... [more]

The aircraft ground deicing (AGD) process is a mandatory step before taking off in a cold climate. The development of CFD (computational fluid dynamics) tools to simulate AGD could help the industry reduce its costs and limit pollution. Previous works have modelled some parts of the AGD process. Building on these previous works, this paper presents a three-dimensional (3D) CFD algorithm to simulate the process in full scale. The algorithm comprises a multi-region model where a Lagrangian method solves the spray particle equations, and an enthalpy−porosity approach with an Eulerian method simulates the ice melting. The multi-region approach is verified in this paper through a spray-tip penetration (STP) test. The STP predicted using the multi-region model had 99% agreement with the STP predicted using a Lagrangian method. Therefore, the multi-region technique correctly modeled the particle momentum between the two regions. This paper also presents a numerical calibration of the permeabi... [more]

This paper is concerned with the issue of the diagnostics of process faults and the detection of cyber-attacks in industrial control systems. This problem is of significant importance to energy production and distribution, which, being part of critical infrastructure, is usually equipped with process diagnostics and, at the same time, is often subject to cyber-attacks. A commonly used approach would be to separate the two types of anomalies. The detection of process faults would be handled by a control team, often with a help of dedicated diagnostic tools, whereas the detection of cyber-attacks would be handled by an information technology team. In this article, it is postulated here that the two can be usefully merged together into one, comprehensive, anomaly detection system. For this purpose, firstly, the main types of cyber-attacks and the main methods of detecting cyber-attacks are being reviewed. Subsequently, in the analogy to “process fault”—a term well established in process d... [more]

In this paper, a study was completed investigating the financial viability of a 5 MW solar power plant in Montenegro with direct access to the market, rather than a long-term power purchase agreement. The empirical research included an econometric analysis and forecast of the prices on the exchange market, using two methods, autoregressive integrated moving average (ARIMA) and neural network auto regression (NNAR), which are compared to the forecast electricity prices. The former was used in order to obtain the electricity prices forecast, since it showed significantly better predictive performances. Consequently, the financial analysis results indicated this business strategy is a financially more viable option, even though it implies increased risks. All investigated metrics and sensitivity analysis pointed in favor of this option, which has significantly higher profitability with a shorter payback period, compared to the usual market strategy. The main conclusion and recommendation... [more]

Many countries are pursuing energy security (ES) in their economies while implementing sustainable development goals (SDGs). Relevant policies may include: (1) access to efficient alternative and preferably renewable energy sources (RESs); and (2) reductions in conventionally obtained energy consumption. As the demand for energy is growing and alternative energy resources are expensive, new ways of financing projects to improve ES are of special interest, e.g., issuing green bonds. In such cases, the obtained funds are allocated to projects that can both improve ES and help to achieve SDGs. The aim of the study was to explore the dependences (in the sense of Granger causality) between the green bond (GB) market, different aspects of sustainable development, as measured by global indicators taken from a family of environmental NASDAQ OMX indices, and ES represented by crude oil prices. The methodology is based on the vector autoregression model. The findings reveal evidence of a short-t... [more]

The automated evaluation of machine conditions is key for efficient maintenance planning. Data-driven methods have proven to enable the automated mapping of complex patterns in sensor data to the health state of a system. However, generalizable approaches for the development of such solutions in the framework of industrial applications are not established yet. In this contribution, a procedure is presented for the development of data-driven condition monitoring solutions for industrial hydraulics using supervised learning and neural networks. The proposed method involves feature extraction as well as feature selection and is applied on simulated data of a hydraulic press. Different steps of the development process are investigated regarding the design options and their efficacy in fault classification tasks. High classification accuracies could be achieved with the presented approach, whereas different faults are shown to require different configurations of the classification models.

Nowadays, cognitive computing has become the popular solution to many problems arising in the energy industry, such as the creation of renewable technologies, energy saving, and searching for new sources. Last decade, a substantial number of scientific papers aiming to support these tasks were published. On the other hand, some years ago, the “cognitive enterprise” (CE) concept was introduced by the IBM company, which assumes, among others, the cognitive technologies used to increase enterprise intelligence. On the road to obtaining the status of a “cognitive enterprise”, it should overcome many challenges. Thus, the aim of the paper was to analyze the current state of research on the application of cognitive computing in the energy industry and to define the trends, challenges, milestones, and perspectives in scientific work’s development. The aim has been achieved using the bibliometric approach. The preliminary analysis was made by Web of Science data sources; 4182 records were retr... [more]

Multi-speed transmission is the main development direction of hybrid transmission, which has brought higher shift quality requirements than traditional fuel vehicle transmission. However, there is less research on the shifting control of hybrid transmission, especially for the shifting control of dedicated hybrid transmission (DHT), which uses the wet clutch as a shift element. This paper studies the power-on downshift process of a two-speed series-parallel hybrid transmission, proposes a shifting control strategy based on motor active speed regulation, and deeply analyzes the causes of maximum impact during the shifting process. The results show that the reverse torque produced in the process of eliminating the remaining slip is the root cause of the maximum impact. On this basis, two optimization strategies are proposed to reduce the shift impact and improve the shift quality. The simulation results show that the proposed optimization strategies can effectively suppress the shift imp... [more]

The maintenance of wireless sensor networks involves challenges such as the periodic replacement of batteries or energy sources in remote locations that are often inaccessible. Therefore, onboard energy harvesting solutions can provide a viable alternative. Experimental energy harvesting from fluid flow, specifically from air flow, is typically restricted to a rotor and stator design or a model that strikes a piezoelectric. On the other hand, energy harvesting from mechanical vibrations routinely uses the linear motion of a magnet passing through a coil or vibrating piezoelectric elements. In this paper, we propose a novel V-twin harvester design that converts wind energy from a rotational input into the linear motion of a magnet inside a coil via a crank-slider mechanism. This design allows for high performance with a smoother voltage output when compared to a reference rotor/stator harvester design or piezoelectric method. At 0.5 Hz, a single crank-slider generated a voltage of 0.176... [more]