ABE can be used as an alternative fuel for engines. This paper studies the combustion and emission performances of an SI engine with GPI plus ABEDI at different engine speeds and loads. The engine operating conditions included speeds of 1000−2600 rpm at the MAP = 50 kPa and loads of MAP = 30−70 kPa at a speed of 1800 rpm. The ABEDIr contained 0%, 20%, 40%, 60%, 80%, and 100%. At speeds = 1000−1800 or 2200−2600 rpm, the testing results showed the ABEDIr corresponding to the maximum IMEP at 80% or 100%. When the ABEDIr = 60%, HC and NOx emissions were the lowest at speeds of 1000−2600 rpm. Meanwhile, NPN and APN both decreased with the increasing of ABEDIr. As the MAP increased, CA0-90 decreased. At different loads, ABE-added fuels had lower HC and NOx emissions and higher IMEP values than pure gasoline. PN was lower than 4 × 104 n/cm3 when the ABEDIr was over 80%. Overall, 80% ABEDIr is a great choice for engine performance at the test range of loads and speeds, and pure ABE fuel is bet... [more]

Thermal response time is an important parameter for the control of fast reactors. Modern thermal hydraulic codes allow for the modeling of transient responses and can also be used to understand the dominant factors that affect them. However, simulations can be computationally expensive, particularly for performing parametric analyses of how thermophysical properties affect transient behavior. Here, we present a method for using linear stability analysis to estimate thermal response time and determine the key parameters that affect transient behavior without performing a forward simulation. The approach can also be used to corroborate simulation results and is tested against simulation results produced with a 2D finite difference model. The results show that this approach produces time-dependent temperature profiles that are within 2 × 10−5−0.1% of the numerical results for a single node perturbation. Changes in temperature have the greatest effect on thermal response time, followed by... [more]

Two interconnected AC microgrids are proposed based on three renewable energy sources (RESs): wind, solar, and biogas. The wind turbine drives a permanent magnet synchronous generator (PMSG). A solar photovoltaic system (SPVS) with an appropriate inverter was incorporated. The biogas genset (BG) consists of a biogas engine coupled with a synchronous generator. Two interconnected AC microgrids, M1 and M2, were considered for study in this work. The microgrid M2 is connected to a diesel engine (DE) characterized by a continuous power supply. The distribution power loss of the interconnected AC microgrids comprises in line loss. The M1 and M2 losses are modeled as an objective function (OF). The power quality enhancement of the interconnected microgrids will be achieved by minimizing this OF. This research also created a unique frequency control method called virtual inertia control (VIC), which stabilizes the microgrid frequency using an optimal controller. In this paper, the following f... [more]

In this paper, the efficiency benefits of adopting Silicon−Carbide devices for electric vehicle applications are studied. A hybrid time and frequency domain-based simulation tool is developed for the Silicon−Carbide (SiC) traction inverter modeling. The tool provides steady-state results with comparable accuracy to standard time domain methods and achieves a factor of thousand reductions in time when simulating a large number of operating points. Especially, the impact of temperature-dependent device losses has been considered to ensure the simulation precision. Next, a vehicle-level modeling is developed to evaluate the impact of the inverter efficiency on the endurance mileage increase of vehicles. It is found that, by applying Silicon−Carbide devices, the energy consumption of the inverter can be greatly reduced by 3/4 under WLTC (World light light-duty vehicle test cycle) profile. It can be transformed into a mileage endurance increase of 3−5%. The impact of the drive cycle profile... [more]

The regenerator plays an extremely important role in the Stirling circulation. A grid regenerator can be used for inverse Stirling machines at room temperature due to its low flow resistance. This paper proposes a hexagonal grid regenerator to theoretically explore heat transfer properties in the inverse Stirling cycle and establishes an approximate analytical model to analyze the effect mechanism of working frequency, thermal diffusivity and wall thickness on the oscillation flow. The results show that the wall thickness is one of the key factors affecting the equivalent heat transfer coefficient. Specifically, too small or too large wall thickness increases the instability of the heat transfer process. The ultimate wall thickness is determined by the equivalent heat transfer coefficient and thermal penetration depth, whose optimal value ensures not only sufficient heat exchange but also the full utilization of materials. With the increase in frequency, heat exchange performance is im... [more]

This paper proposes a novel regional carbon emission inequality (RCI) index based on a special kind of general distribution. Using the proposed RCI index and based on China’s county-level panel data over the time span of 1997−2017, the regional carbon emission inequality of China is evaluated at intra-provincial, sub-national, and national levels. Based on that, the dependence between regional carbon inequality and carbon efficiency is studied by using copula functions and nonlinear dependence measures. The empirical results show that: (1) Shanghai, Tianjin, and Inner Mongolia have the worst carbon inequalities; while Hainan, Qinghai, and Jiangxi are the three most carbon-equal provinces; (2) there is a divergence phenomenon in RCI values of municipalities over the past decade; (3) from the national-level perspective, the inter-provincial carbon emission inequality is much greater than that at the intra-provincial level; (4) from the sub-national-level perspective, the east region has... [more]

In order to find out the enrichment mechanism and forming type of deep shale gas, taking the Longmaxi Formation shale in the Desheng−Yunjin Syncline area of Sichuan Basin as an example, we determined the mineralogy, organic geochemistry, physical property analysis, gas and water content, and the influence of three factors, namely sedimentation, structural conditions, and hydrogeological conditions, on the enrichment of shale gas. The results show that Longmaxi Formation shale in Desheng−Yunjin Syncline area is a good hydrocarbon source rock that is in the over-mature stage and has the characteristics of high porosity, low permeability, and high-water saturation. The contents of clay and quartz are high, and the brittleness index is quite different. According to the mineral composition, nine types of lithofacies can be found. The development characteristics of Longmaxi Formation shale and the sealing property of the roof have no obvious influence on the enrichment of shale gas, but the... [more]

Shear velocity is an important parameter in pre-stack seismic reservoir description. However, in the real study, the high cost of array acoustic logging leads to lacking a shear velocity curve. Thus, it is crucial to use conventional well-logging data to predict shear velocity. The shear velocity prediction methods mainly include empirical formulas and theoretical rock physics models. When using the empirical formula method, calibration should be performed to fit the local data, and its accuracy is low. When using rock physics modeling, many parameters about the pure mineral must be optimized simultaneously. We present a deep learning method to predict shear velocity from several conventional logging curves in tight sandstone of the Sichuan Basin. The XGBoost algorithm has been used to automatically select the feature curves as the model’s input after quality control and cleaning of the input data. Then, we construct a deep-feed neuro network model (DFNN) and decompose the whole model... [more]

In view of the current multi-source information scenario, this paper proposes a decision-making method for electric vehicle charging stations (EVCSs) based on prospect theory, which considers payment cost, time cost, and route factors, and is used for electric vehicle (EV) owners to make decisions when the vehicle’s electricity is low. Combined with the multi-source information architecture composed of an information layer, algorithm layer, and model layer, the load of EVCSs in the region is forecast. In this paper, the Monte Carlo method is used to test the IEEE-30 model and the traffic network based on it, and the spatial and temporal distribution of charging load in the region is obtained, which verifies the effectiveness of the proposed method. The results show that EVCS load forecasting based on the prospect theory under the influence of multi-source information will have an impact on the space−time distribution of the EVCS load, which is more consistent with the decisions of EV o... [more]

Recently, we identified two types (A and B) of energy processes that naturally occur on Earth. Type-A energetic process such as the classical heat engines follows well the thermodynamic second law; Type-B energy process follows the first law of thermodynamics, but does not have to be constrained by the second law, owning to its special asymmetric function. The identification of type-B process inspired a novel invention on isothermal electricity production through an asymmetric function-gated power generation system. This article highlights the fundamental embodiments, scientific principles, and physics equations for the asymmetric function-gated isothermal electricity generator that comprises an exceptionally low electron-work-function surface as an isothermal electron emitter and a space gap that permits the isothermally emitted electrons to travel ballistically to a collector. The physics equations for the density of isothermal electricity current, voltage and power all clearly show... [more]

This article presents an integrated approach for solving the optimization of economic dispatch and commitment EDC problems of hybrid thermosolar concentrating power generating systems using matrix mathematics. The model uses matrices, and is solved by matlab programming. The study case of a hybrid thermosolar system in the north-west of Greece shows the impact of concentrating solar power (CSP) generation on the optimal cost of energy produced: the CSP system increases the operational costs as compared to the fossil fuel thermal systems. To acquire the benefits of cleaner electric energy with diminished emissions versus the minimal cost of electrical energy generation belongs to multicriteria managerial decisions. This approach can be applied to hybrid energy systems with large numbers of thermal and CSP generators. It offers an accurate instrument to energy engineers and researchers, for critical managerial decisions regarding electrical energy economics.

This paper aims to develop a review of the electrokinetic flow in microchannels. Thermal characteristics of electrokinetic phenomena in microchannels based on the Poisson−Boltzmann equation are presented rigorously by considering the Debye−Hückel approximation at a low zeta potential. Several researchers developed new mathematical models for high electrical potential with the electrical double layer (EDL). A literature survey was conducted to determine the velocity, temperature, Nusselt number, and volumetric flow rate by several analytical, numerical, and combinations along with different parameters. The momentum and energy equations govern these parameters with the influences of electric, magnetic, or both fields at various preconditions. The primary focus of this study is to summarize the literature rigorously on outcomes of electrokinetically driven flow in microchannels from the beginning to the present. The possible future scope of work highlights developing new mathematical anal... [more]

This work focuses on detailed descriptions of DC discharge properties in supersonic airflow and its applicability in combustion simulations. Due to the complexity of obtaining most of the data in the experiment, our experimental research was supplemented by a numerical simulation. Two packages, i.e., FlowVision (fast commercial CFD for 3D engineering) and Plasmaero (2D scientific code developed in JIHT RAS for MHD tasks), were used for modeling the arc DC discharge in a supersonic flow at Mach (M) = 2. Both will be considered for further use in plasma-assisted combustion modeling, so it is important to validate both codes using experimental data from the model configuration with discharge. Axisymmetric geometries of experiments with two coaxial electrodes located parallel to the flow were chosen to avoid the appearance of the current channel part perpendicular to the flow and the corresponding discharge pulsations. Such geometries allow performing numerical simulations in 2D formulatio... [more]

Current software solutions for solar-radiation modeling in 3D focus on the urban environment. Most of the published tools do not implement methods to consider complex objects, such as urban greenery in their models or they expect a rather complex 3D mesh to represent such objects. Their use in an environment that is difficult to represent geometrically, such as vegetation-covered areas, is rather limited. In this paper, we present a newly developed solar-radiation tool focused on solar-radiation modeling in areas with complex objects, such as vegetation. The tool uses voxel representations of space based on point-cloud data to calculate the illumination and ESRA solar-radiation model to estimate the direct, diffuse, and global irradiation in a specified time range. We demonstrate the capabilities of this tool on a forested mountain area of Suchá valley in the Hight Tatra mountains (Slovakia) and also in the urban environment of Castle Hill in Bratislava (Slovakia) with urban greenery.... [more]

Microgrids (MGs) and networked (interconnected) microgrids (NMGs) are emerging as an efficient way for integrating distributed energy resources (DERs) into power distribution systems. MGs and NMGs can disconnect from the main grid and operate autonomously, strengthen grid resilience, and help mitigate grid disturbances and maintain power quality. In addition, when supported by sophisticated and efficient management strategies, MGs and NMGs have the ability to enhance power supply reliability. However, their deployment comes with many challenges, in particular regarding the efficient management of DERs. That is why a survey of recent advances in the smart management—the term refers to a variety of planning and control tasks—of MGs and NMGs is presented in this paper. It aims at establishing a picture of strategies and identifying trends in methods. The reader is provided with an in-depth analysis of a variety of papers recently published in peer-reviewed journals: the way the methods ar... [more]

Pole-phase changing induction machines (IMs) offer the capability to extend the torque-speed envelope compared to their fixed pole-phase counterparts. Dynamic pole-changing can achieve higher torque levels at lower speeds, utilizing higher pole numbers, and extended flux-weakening range with lower pole-number operations. This paper investigates the design impact on the optimum pole-phase changing behavior and respective split of the operating region to different pole-phase operations. Additionally, the improvement in terms of the overall torque per ampere capability and efficiency is illustrated. For the purposes of the analysis, two different IMs with wound independently-controlled stator coils (WICSC) and different original pole numbers are evaluated in an effort to quantify the extent of the benefits of pole-phase changing. These geometries correspond to machines that were originally designed with 2- and 6 magnetic poles, respectively. It is shown that, in the case of the original 2... [more]

Safety and critical applications employ fault-tolerant control systems (FTCS) to increase reliability and availability in the event of a failure of critical components. Process facilities may employ these technologies to cut down on production losses caused by equipment failures that occur on an irregular or unscheduled basis. Air−fuel ratio (AFR) adjustment in the fuel system of internal combustion engines (ICE) is crucial for enhancing engine efficiency, saving fuel energy, and safeguarding the environment. This paper proposes a novel hybrid fault-tolerant control system (HFTCS) for controlling the AFR in ICEs that combines the features of both an active fault-tolerant control system (AFTCS) and a passive fault-tolerant control system (PFTCS). The fault detection and isolation (FDI) unit is designed using fuzzy logic (FL) as part of an AFTCS to give estimated sensor values to the engine controller when the sensor becomes faulty. Super-twisting sliding mode control (ST-SMC) is impleme... [more]

A qualitative evaluation was performed by comprehensively considering the lighting environment of each staircase of 20 railway stations in Tokyo, the width of the stairs, the type of ceiling, wall lighting fixtures, and the color. As a result of the quantitative evaluation of 20 stairs, it was found that a difference of up to 400 lx occurred in the measurement results of the entrance, exit, and middle landing, even for the same stairs. As a result of qualitative evaluation, it was found that the quantitative evaluation result and the simple proportional relationship were not established. It was found that simply physically brightening a space cannot make a comfortable and safe space, and in some cases, glare is likely to occur. As a result of the analysis of variance and correlation analysis, it was found that the characteristics of the space, especially the material of the wall and the location of the lighting equipment, had a large effect on the impression of the space. As a result o... [more]

This paper presents the implementation of a fuzzy control strategy for speed regulation of an electromagnetic frequency regulator (EFR) prototype, aiming to eliminate the dependence on knowledge of physical parameters in the most diverse operating conditions. Speed multiplication is one of the most important steps in wind power generation. Gearboxes are generally used for this purpose. However, they have a reduced lifespan and a high failure rate, and are still noise sources. The search for new ways to match the speed (and torque) between the turbine and the generator is an important research area to increase the energy, financial, and environmental efficiency of wind systems. The EFR device is an example of an alternative technology that this team of researchers has proposed. It considers the main advantages of an induction machine with the rotor in a squirrel cage positively. In the first studies, the EFR control strategy consisted of the conventional PID controllers, which have seve... [more]

Currently, AC motors are a key element of industrial and commercial drive systems. During normal operation, the machines may become damaged, which may pose a threat to the users. Therefore, it is important to develop a fault detection method that allows for the detection of a fault at an early stage. Among the currently used diagnostic systems, applications based on deep neural structures are dynamically developed. Despite many examples of applications of deep learning methods, there are no formal rules for selecting the network structure and parameters of the training process. Such methods would make it possible to shorten the implementation process of deep networks in diagnostic systems of AC machines. The article presents a detailed analysis of the influence of deep convolutional network hyperparameters and training procedures on the precision of the interturn short-circuits detection system. The studies take into account the direct analysis of phase currents through the convolution... [more]

The paper aims to give a universal methodology for assessing the storage capacity of a bedded rock salt formation in terms of the operational and strategic storage facilities for liquid fuels. The method assumes the development of a geological model of the analyzed rock salt formation and the determination of the salt caverns’ size and spacing and the impact of convergence on their capacity during operation. Based on this method, the paper presents calculations of the storage capacity using the example of the bedded rock salt formations in Poland and their results in the form of storage capacity maps. The maps show that the analyzed rock salt deposits’ storage capacity in northern Poland amounts to 7.1 B m3 and in the Fore-Sudetic Monocline to 10.5 B m3, in the case of strategic storage facilities. The spatial analysis of the storage capacity rasters, including determining the raster volumes and their unique values, allowed us to quantify the variability of the storage capacity in the... [more]

Nuclear thermal propulsion is an enabling technology for future space missions, such as crew-operated Mars missions. Nuclear thermal propulsion technology provides a performance benefit over chemical propulsion systems by operating with light propellants (e.g., hydrogen) at elevated engine chamber conditions. Therefore, nuclear thermal propulsion reactor cores exhibit high propellant velocities and elevated propellant and fuel temperatures, subsequently leading to relatively high thermal stresses and geometrical deformation. This paper details the numerical approach to solve the thermo-elastic equations, which was implemented into the recently developed ntpThermo code. In addition, this paper demonstrates the extension of the Basilisk multiphysics framework to perform full-core coupled neutronic, thermal-hydraulic, and thermo-mechanical analysis of nuclear thermal propulsion reactors. The analyses demonstrate and quantify thermo-mechanical feedback, which for the investigated cases, ac... [more]

Improving the efficiency of transport of coal water slurries (CWSs) and determining pipe wear both necessitate accurate predictions of flow characteristics in pipelines with complex geometries. At the bends of the channels, the flow is significantly influenced by the bend curvature, flow rate, and the rheological properties of the slurries that are viscoplastic. Herein, we numerically simulated the flow of CWS in curved channels with different curvature ratios, at different flow rates, and using different rheological models, respectively. The results showed that, due to the yield stress on the cross-stream slices, the velocity profiles showed an unyielded plug. The plug deflects outwards in most circumstances, except at the bend core in the highly curved channel, and, at the same time, at the lower conveying rate, which is due to the fact that the larger inner-wall-pointed pressure gradient has to be balanced by large velocities at the inner bend and, hence, the centrifugal effects are... [more]

The wind farm market in Poland evolved very dynamically in the years 2000−2015. Unfortunately, the high public resistance caused the government in 2016 to freeze the development of this industry by introducing a restrictive act, which practically stopped the wind farm industry overnight. The climate aspects, such as reduction of the carbon footprint, which have been considered and widely discussed for several years at the European Union forums, were a chance to change this situation. The new regulations gave hope that the wind energy industry in Poland would soon be unblocked, unfortunately the commitment to coal was still an effective barrier, which is clearly visible in the presented study. The Russian aggression against Ukraine, which resulted in a blockade of hydrocarbon imports, has completely changed the center of gravity of the Polish energy and heating economy. The article focuses on the accelerated changes in the renewable energy sources (RESs) and the related legislation, esp... [more]

This article reviews the issue of the use of cryptocurrencies (crypto-assets, in general) for an electricity settlement system. The development of digital techniques, including blockchain-based mechanisms, has meant that an increased interest in blockchain-based solutions is to be expected. Blockchain and similar approaches are characterised by decentralisation, so they are concurrent with the trends of the transforming power sector. Decentralised energy generation based on a high proportion of prosumer installations requires the implementation of a new settlement system for grid activities related to electricity use. The first projects of such systems based on a dedicated cryptocurrency have emerged. Based on these, the general concept of such a system with its own cryptocurrency called CCE is presented, including variants implementing net-metering and net-billing. Furthermore, issues requiring interdisciplinary research work and discussion before implementing such systems were identi... [more]