This study investigated how, through knowledge calibration and a causal path model, psychological distance can explain the level of satisfaction with nuclear energy policy. The investigation used multiple regression analysis and path analysis to explore relationships among variables. Data from 1056 adults revealed that more knowledge-calibrated individuals have more positive attitudes toward nuclear energy policy. In addition, the psychological distance influences policy satisfaction by mediation of perceived risk of nuclear energy. This study aimed to increase the understanding of the dynamic of satisfaction with and acceptance of nuclear energy policy among stakeholders. Thus, based on the construal level theory, the study addressed the importance of knowledge and psychological distance in explaining variation in satisfaction and acceptance about nuclear policy.

A wind turbine tower assembly is presented, consisting of a lower “tripod section” and an upper tubular steel section, aiming at enabling very tall hub heights for optimum exploitation of the wind potential. The foundation consists of sets of piles connected at their top by a common pile cap below each tripod leg. The concept can be applied for the realization of new or the upgrade of existing wind turbine towers. It is adjustable to both onshore and offshore towers, but emphasis is directed towards overcoming the stricter onshore transportability constraints. For that purpose, pre-welded individual tripod parts are transported and are then bolted together during erection, contrary to fully pre-welded tripods that have been used in offshore towers. Alternative constructional details of the tripod joints are therefore proposed that address the fabrication, transportability, on-site erection and maintenance requirements and can meet structural performance criteria. The main structural fe... [more]

The line-commutated converter (LCC)-based high voltage direct current (HVDC) technology has been widely applied on long-distance and bulk-capacity power transmission occasions. Due to the terrible interferences in the vicinity of communication lines, DC filters (DCFs) are always installed to mitigate the interferences within acceptable levels for almost all in-service overhead line transmission LCC-HVDC schemes. With the rapid development of the communication technology, however, the anti-interference capability of the telephone system has been remarkably improved. Thus, the original purpose of employing DCFs has been virtually absent, and the necessity of the DCFs shall be re-evaluated in sufficient depth not only for new LCC-HVDC projects, but also in the case of refurbishment of older projects. To demonstrate this constructive topic, this paper carries out a commercial ±800 kV/8000 MW LCC-HVDC project as an illustrative example to analyze and discuss those crucial aspects, which may... [more]

Thermomagnetic energy harvesters are one form of technology that can be effectively used to extract energy from low grade heat sources, without causing damage to the environment. In this study, we investigated the output performance of our previously designed thermomagnetic heat engine, which was developed to extract thermal energy by exploiting the magnetocaloric effect of gadolinium. The proposed heat engine uses water as the heat transfer fluid, with heat sources at a temperature in the range 20−65 °C. Although this method turned out to be a promising solution to extract thermal energy, the amount of energy extracted through this geometry of thermomagnetic engine was limited and depends on the interaction between magnetic flux and magnetocaloric material. Therefore, in this paper we carry out an in-depth analysis of the designed thermomagnetic heat engine with an integrated approach of numerical simulation and experimental validation. The computational model improved recognition of... [more]

The solar chimney is one of the uninvestigated areas in the possible selection in the field of renewable solar energy utilization. CFD can be demonstrated as a useful tool of figure confidence in the design and employment of a solar chimney. A realistic numerical model for a solar-based updraft power plant for power generation was established through this research work. Iraqi weather in Kirkuk, northern Iraq was considered for this case study. A three-dimensional (3D) simulation of the main geometric dimensions of the Spanish, Manzanares model integrated with a real turbine was performed using computational fluid dynamics (CFD). The turbulent model of RNG k-e, the nongrey discrete coordinate (DO) radiation model, and the solar raytracing algorithm were used. It was observed that the air velocity below the turbine was graded according to the seasons of the year and was at its maximum in July with 18.28 m/s due to the high ambient temperature, and the lowest value was recorded in January... [more]

In this paper, a prediction method of the heat transfer coefficient of composite vacuum glazing (CVG) is proposed. By analyzing the heat transfer process of CVG, the theoretical calculation formula for the heat transfer coefficient of CVG is established. CVG temperature variation under the test conditions specified in the national standard is simulated using ANSYS. The CVG heat transfer coefficient is calculated by combining the theoretical formula and simulation results. The simulation results are then verified by comparison to a physical experiment. The results show that the deviations between the experimental and predicted values are ≤3.8%, verifying the accuracy of the simulation results and proving that the model can be used in engineering practice. Furthermore, the effects of different coating positions on the heat transfer performance of CVG are studied. The results show that different coating positions have a significant impact on the heat transfer coefficient of CVG. The heat... [more]

Nanofluids as an EOR technique are reported to enhance oil recoveries. Among all the nanomaterial silica with promising lab results, economic and environmental acceptability are an ideal material for future applications. Despite the potential to enhance recoveries, understanding the two-fold impact of parameters such as concentration, salinity, stability, injection rate, and irreproducibility of results has arisen ambiguities that have delayed field applications. This integrated study is conducted to ascertain two-fold impacts of concentration and salinity on recovery and stability and evaluates corresponding changes in the recovery mechanism with variance in the parameters. Initially, silica nanofluids’ recovery potential was evaluated by tertiary flooding at different concentrations (0.02, 0.05, 0.07, 0.1) wt. % at 20,000 ppm salinity. The optimum concentration of 0.05 wt. % with the highest potential in terms of recovery, wettability change, and IFT reduction was selected. Then nano... [more]

Throughout decades, conflicts related to the access and usage of various energy sources have caused political tensions between nations and confederations of states. Thus, partially to decrease the dependence on fossil fuels, a thorough transition towards renewable energies has been promoted by several regional and national governments as well as by multinational institutions such as the European Union. In this context, the automotive industry has particularly been held responsible for the production of negative externalities, such as global greenhouse gas emissions (GHG emissions), noise and air pollution. To a notable extent, these externalities were caused by vehicles running on fossil fuels such as petroleum products, including gasoline, diesel fuel and fuel oil. Accordingly, it is often argued that replacing vehicles run by internal combustion engines (ICEs) with so-called alternative fuel vehicles (AFVs), particularly with plug-in electric vehicles (PEVs), is crucial to increase t... [more]

Fly ash cement is used to solidify marine clay to prepare marine-clay-based cemented paste backfill (MCCPB) to fill the underground goaf of mines, which not only utilizes solid waste such as fly ash and marine clay, but also controls surface subsidence and protects the environment. To simulate the complex underground mine water environment of the filling body, a dry-wet cycle aquatic environment test under different material ratios and curing ages was designed. The water absorption and unconfined compression strength (UCS) of MCCPB with curing ages of 7 and 28 days under the action of 0, 1, 3, and 7 dry-wet cycles were investigated. The results indicate as the number of dry-wet cycles increases, the surface of MCCPB becomes significantly rougher, and the water content and the solid mass decrease accordingly. Different ratios and curing ages of MCCPB in dry-wet cycles of the UCS tend first to increase, then decrease. Meanwhile, the stress-strain curve of the specimen shows that the tren... [more]

A comparative analysis of energy poverty transitions and persistence can provide valuable suggestions for long-term policy actions. This study examines the dynamics of energy poverty in 17 European countries based on the longitudinal household data from the EU Survey on Income and Living Conditions, waves 2015−2018. The study pursues two goals. First, we explore households’ chances of transitioning in and out of energy poverty in each country following the discrete-time Markov process. On average, the probability to stay in energy poverty is 51.5%, and there is a lot of heterogeneity across countries. Households in Bulgaria, Greece, Romania, and Lithuania are quite close to the energy poverty trap. Second, we identify factors that help energy-poor households leave energy poverty. Demographic, technical, and socio-economic factors are the drivers in escaping energy poverty, which suggests common EU policy.

Synchronous effects of biochar on heavy metals stress, microbial activity and nodulation process in the soil are rarely addressed. This work studied the effects, under greenhouse conditions, of selected heavy metals Cd2+, Pb2+ and Ni2+ on soybean plants grown in two different soils amended with biochar, and studied their effect on the microbial and enzymatic activity. As a result of the interference between heavy metals and biochar, biochar overcame heavy metal problems and maintained a microbial population of major groups (bacteria−fungi). There was an increase in the degree of resistance (RS) of the major microbial groups to heavy metals when biochar was added to the soil under study. Numbers of bacterial nodules significantly increased, particularly by using the higher rate of biochar compared to the control, either by adding biochar alone or by mixing it with the selected heavy metals. The arginase activity was increased by 25.5% and 37.1% in clay and sandy soil, respectively, comp... [more]

Hydrogen energy is a very attractive option in dealing with the existing energy crisis. For the development of a hydrogen energy economy, hydrogen storage technology must be improved to over the storage limitations. Compared with traditional hydrogen storage technology, the prospect of hydrogen storage materials is broader. Among all types of hydrogen storage materials, solid hydrogen storage materials are most promising and have the most safety security. Solid hydrogen storage materials include high surface area physical adsorption materials and interstitial and non-interstitial hydrides. Among them, interstitial hydrides, also called intermetallic hydrides, are hydrides formed by transition metals or their alloys. The main alloy types are A2B, AB, AB2, AB3, A2B7, AB5, and BCC. A is a hydride that easily forms metal (such as Ti, V, Zr, and Y), while B is a non-hydride forming metal (such as Cr, Mn, and Fe). The development of intermetallic compounds as hydrogen storage materials is ve... [more]

This paper presents a new intelligent islanding detection scheme (IIDS) based on empirical wavelet transform (EWT) and long short-term memory (LSTM) network to identify islanding events in microgrids. The concept of EWT is extended to extract features from three-phase signals. First, the three-phase voltage signals sampled at the terminal of targeted distributed energy resource (DER) or point of common coupling (PCC) are decomposed into empirical modes/frequency subbands using EWT. Then, instantaneous amplitudes and instantaneous frequencies of the three-phases at different frequency subbands are combined, and various statistical features are calculated. Finally, the EWT-based features along with the three-phase voltage signals are input to the LSTM network to differentiate between non-islanding and islanding events. To assess the efficacy of the proposed IIDS, extensive simulations are performed on an IEC microgrid and an IEEE 34-node system. The simulation results verify the effectiv... [more]

A floor rock roadway under an oblique straddle working face is a typical dynamic pressure roadway. Under the complex disturbance of excavation engineering works, the roadway often undergoes stress concentration and severe deformation and damage. To solve the problem of surrounding rock stability control for this roadway type, this study considered the East Forth main transport roadway in the floor strata of the 1762(3) working face of the Pansan coal mine. In situ ground pressure monitoring and numerical simulation calculation using the FLAC2D software were carried out. The influence laws of the surrounding rock lithology, the vertical and horizontal distance between the roadway and overlying working face, the positional relationship between the roadway and the overlying working face, and the support form and strength of the rock surrounding an oblique straddle roadway were obtained. Within the range of mining influence, the properties of the rock surrounding the roof and floor were ve... [more]

In this paper, we present a nonlinear PID controller based on saturation functions with variable parameters in order to regulate the output voltage of a buck converter in the presence of changes in the input voltage. The main feature of the proposed controller is to bound the control input with a variable parameter to avoid the windup effect generated by the combination of the integral control action and some operation conditions. The main advantages of the proposed nonlinear PID controller are its low computing cost and the simple tuning task to implement the control strategy in an embedded system. The acceptable behavior of the closed-loop system is presented through the simulation and experimental results.

The condition monitoring of induction motors (IM), is an important concern for industry due to the widespread use of these machines. Magnetic Flux Analysis, has been proven to be a reliable method of diagnosing these motors. Among the IM types, squirrel-cage motors (SCIM) are one of the most commonly used. In many industrial applications, the IM are driven by different types of starters, quite often by soft-starters. Despite rotor damages are more prone to occur in line-started motors, these kind of failures have been also reported in those ones driven by soft-starters. Related to this, the use of these type of starters may introduce some harmonic components, that could veil the magnetic flux signature of the different rotor faults. So, the aim of this study is to confirm if the Stray Flux Analysis technique maintains its reliability in these cases. Thus, this article presents the results of soft-started induction motors start-up tests, both in healthy and faulty motors. The fault comp... [more]

In the present work, a network model for the numerical resolution of the heat transport problem in porous media coupled with a water flow is presented. Starting from the governing equations, both for 1D and 2D geometries, an equivalent electrical circuit is obtained after their spatial discretization, so that each term or addend of the differential equation is represented by an electrical device: voltage source, capacitor, resistor or voltage-controlled current source. To make this possible, it is necessary to establish an analogy between the real physical variables of the problem and the electrical ones, that is: temperature of the medium and voltage at the nodes of the network model. The resolution of the electrical circuit, by means of the different circuit resolution codes available today, provides, in a fast, simple and precise way, the exact solution of the temperature field in the medium, which is usually represented by abaci with temperature-depth profiles. At the end of the ar... [more]

This paper presents the design and optimization of a wireless power transfer (WPT) charging system based on magnetically coupled resonant technology, applied to an Unmanned Aerial Vehicle (UAV). In this paper, a charging system, including dual active transmitter coils and a single receiver coil, is proposed. The dual transmitting coils adopt a coaxial structure with different radii. This structure simplifies the calculation of the complex mutual inductance between the coils to a function of mutual inductance only related to the value of the radial misalignment. Aiming toward a constant charging power, the optimal transmission efficiency of electric energy is achieved by controlling the input voltages of the active coils, which are solved via a set of equations defined as Lagrange multipliers. The simulation results of the 570 V and 85,000 Hz system verified the validity of the proposed wireless UAV charging scheme.

The effect of the traditional energy saving mode on process engineering is decreasing, so the idea of system energy saving is developing vigorously. This paper summarizes the existing studies on energy saving from three aspects—energy saving technology, energy management, comprehensive evaluation or analysis—and clearly finds that related studies on energy saving have been gradually promoted to promote the development of system energy saving in the whole process engineering process. Among them, the calculation of energy saving brought by energy saving technology is a difficult point in the research. This paper proposes a novel calculation method of energy saving by taking the iron and steel production process (ISPP) as an example. According to the actual data provided by a steel plant in China, the calculation method is validated effectively.

This paper presents a systematic topological study to derive all possible basic and non-isolated three-port converters (TPCs) using power flow diagrams. Unlike most reported TPCs with one bidirectional port, this paper considers up to two bidirectional ports and provides a comprehensive analytical tool. This tool acts as a framework for all power flow combinations, selection, and design. Some viable converter configurations have been identified and selected for further analysis.

In order to decarbonize the energy sector, the interdependencies between the power and natural gas systems are going to be much stronger in the next period. Thus, it is necessary to have a powerful simulation model that is able to efficiently and simultaneously solve all coupled energy carriers in a single simulation environment in only one simulation step. As an answer to the described computational challenges, a unique model for the steady-state analysis of a multi-energy system (MES) using the electrical analogy approach is developed. Detailed electrical equivalent models, developed using the network port theory and the load flow method formulation, of the most important natural gas network elements, as well as of the linking facilities between the power and natural gas systems, are given. The presented models were loaded up into a well-known software for the power system simulation—NEPLAN. In the case studies, the accuracy of the presented models is confirmed by the comparison of t... [more]

A microgrid is a small-scale energy system with its own generation and storage facilities and energy management system, which includes shiftable and traditional loads. The purpose of this research is to determine the size of the microgrid through (i) investigating the effect of a shiftable demand response program (DRP) on sizing of an islanded microgrid and (ii) studying the uncertainty of power output of renewable energy sources by applying the robust optimization (RO) method. Since the RO method solves the problem for lower power outputs of renewable energy sources (RES) than the predicted values, the results obtained are pessimistic and will increase the project cost. To deal with the increment of project cost, the application of a load shifting DRP is proposed to reduce the cost. In addition, DRPs are suitable means to reduce the effects of uncertain power sources. Therefore, it is shown that a shiftable DRP is effective in reducing the overall project cost and the dependency on en... [more]

With existing power prediction algorithms, it is difficult to satisfy the requirements for prediction accuracy and time when PV output power fluctuates sharply within seconds, so this paper proposes a high-precision and ultra-fast PV power prediction algorithm. Firstly, in order to shorten the optimization time and improve the optimization accuracy, the single-iteration Gray Wolf Optimization (SiGWO) method is used to simplify the iteration process of the hyperparameters of Least Squares Support Vector Machine (LSSVM), and then the hybrid local search algorithm composed of Iterative Local Search (ILS) and Self-adaptive Differential Evolution (SaDE) is used to improve the accuracy of hyperparameters, so as to achieve high-precision and ultra-fast PV power prediction. The power prediction model is established, and the proposed algorithm is applied in a test experiment which can complete the power prediction within 3 s, and the RMSE is only 0.44%. Finally, combined with the PV-storage adv... [more]

Buildings with solar photovoltaic (PV) generation and a stationary battery energy storage system (BESS) may self-sustain an uninterrupted full-level electricity supply during power outages. The duration of off-grid operation is dependent on the time of the power fault and the capabilities of the home energy management system (HEMS). In this paper, building resilience is quantified by analyzing the self-sustainment duration for all possible power outages throughout an entire year. An evaluation method is proposed and exercised on a reference house in California climate zone 9 for which the detailed electricity usage is simulated using the EnergyPlus software. The influence of factors such as energy use behavioral patterns, energy storage capacity from the BESS, and an electric vehicle (EV) battery on the building resilience is evaluated. Varying combinations of energy storage and controllable loads are studied for optimally improved resilience based on user preferences. It is shown that... [more]

The rising usage of carbon and glass fibers has raised awareness of scrap management options. Every year, tons of composite scrap containing precious carbon and glass fibers accumulate from numerous sectors. It is necessary to recycle them efficiently, without harming the environment. Pyrolysis seems to be a realistic and promising approach, not only for efficient recovery, but also for high-quality fiber production. In this paper, the essential characteristics of the pyrolysis process, their influence on fiber characteristics, and the use of recovered fibers in the creation of a new composite are highlighted. Pyrolysis, like any other recycling process, has several drawbacks, the most problematic of which is the probability of char development on the resultant fiber surface. Due to the char, the mechanical characteristics of the recovered fibers may decrease substantially. Chemically treating and post-heating the fibers both help to reduce char formation, but only to a limited degree.... [more]