Several dynamic projects and fault diagnosis of mechanical structures require the knowledge of the acting external forces. However, the measurement of such forces is often difficult or even impossible; in such cases, an inverse problem must be solved. This paper proposes a force identification method that uses the response surface methodology (RSM) based on central composite design (CCD) in conjunction with a random forest regression algorithm. The procedure initially required the finite element modal model of the forced structure. Harmonic analyses were then performed with varied parameters of forces, and RSM generated a dataset containing the values of amplitude, frequency, location of forces, and vibration acceleration at several points of the structure. The dataset was used for training and testing a random forest regression model for the prediction of any location, amplitude, and frequency of the force to be identified with information on only the vibration acquisition at certain... [more]

The operation and maintenance (O&M) of buildings and infrastructure represent a strategic activity to ensure they perform as expected over time and to reduce energy consumption and maintenance costs at the urban and building scale. With the increasing diffusion of BIM, IoT devices, and AI, the future of O&M is represented by digital twin technology. To effectively take advantage of this digital revolution, thus enabling data-driven energy control, proactive maintenance, and predictive daily operations, it is vital that smart building management exploits the opportunities offered by the extended reality (XR) technologies. Nevertheless, in consideration of the novelty of XR in the AECO sector and its rapid and ongoing evolution, knowledge of the specific possibilities and the methods of integration into the building process workflow is still piecemeal and sparse. With the goal to bridge this gap, the article presents a thorough review of virtual reality (VR), augmented reality (AR), and... [more]

A battery−supercapacitor hybrid energy storage system is investigated as a solution to reduce the high-power delivery stress on the battery. An optimally-sized system can further enhance the storage and cost efficiency. This paper discusses several possible problems in the sizing of a battery−supercapacitor hybrid energy storage system for practical applications. A sizing method that utilises data collected from a fully active embedded control hybrid energy system is proposed. The feasibility of the method is then tested on three load profiles that represent the load demand of inter- and intra-applications with a battery−supercapacitor hybrid energy storage system. The result is compared to a battery-only single energy storage system. The results verified that the number of batteries required in the hybrid energy storage system is reduced by at least 50% compared to the battery-only single energy storage system.

Prior to the commissioning of a new industrial biorefinery it is deemed necessary to evaluate if the new project will be beneficial or detrimental to climate change, one of the main drivers for the sustainable development goals (SDG) of the United Nations. In particular, how SDG 7, Clean and Efficient Energy, SDG 3, Good Health and Well Being, SDG 9, Industry Innovation and Infrastructure, and SDG 12, Responsible Production and Consumption, would engage in a new biorefinery design, beneficial to climate change, i.e., fostering SDG 13, Climate Action. This study uses life cycle assessment methodology (LCA) to delve in detail into the Global Warming Impact category, project scenario GHG savings, using a conventional and a dynamic emission flux approach until 2060 (30-year lifetime). Water, heat and electricity circularity are in place by using a water recirculation process and a combined heat and power unit (CHP). A new historical approach to derive low and higher-end commodity prices (c... [more]

Pollution flashover occurs when soluble and nonsoluble materials cover the surface of an insulator, and this may ultimately cause a reduction in its performance. In this paper, the common type of sodium chloride (NaCl) was used as a soluble pollutant (ESDD) and kaolin as a nonsoluble pollutant (NSDD). Samples of silicone rubber (SiR) insulators were selected for this study and fabricated at the Advanced High Voltage Engineering Research Centre (AHIVEC) at Cardiff University. The samples were preconditioned and polluted according to standard specifications. Additionally, the AC voltage ramp technique was used to achieve flashover (FOV) voltage with different pollution levels. The aim of this work was to investigate the effect of nonsoluble materials on flashover characteristics to understand their interaction with dry-band arcs by using FOV electrical equations and experimental data. The test results show that the FOV voltage of the silicone rubber insulator substantially decreased with... [more]

Loaders are widely used in the construction of earthworks for construction projects. Due to the large volume and mass of these machines, they have shortcomings such as low driving efficiency and high energy consumption. To address these shortcomings, this work applied eclectic drive technology to a loader’s traction system. A wheel electric drive system with a switched reluctance driver (SRD) was developed. The operating principle and basic structure of the SRD system were analyzed. A new voltage PWM-controlled strategy with dynamic adjustable turn-on and turn-off angles and a single conducting phase in a fixed period was developed. Then, an SRD simulation model was established in MATLAB/Simulink. A simulation of the working condition for the loader was performed. A test bench for the SRD was built and accordingly the transportation and operation conditions were tested. The corresponding speed−time curve of transportation and operation was obtained. Simulation and experiment results sh... [more]

This study focuses on the problem of the efficient energy management of an independent fleet of freight electric vehicles (EVs) providing service to a city multi-floor manufacturing cluster (CMFMC) within a metropolis while considering the requirements of smart sustainable electromobility and the limitations of the power system. The energy efficiency monitoring system is considered an information support tool for the management process. An object-oriented formalization of monitoring information technology is proposed which has a block structure and contains three categories of classes (information acquisition, calculation algorithms, and control procedures). An example of the implementation of the class “Operation with the electrical grid” of information technology is presented. The planning of the freight EVs charging under power limits of the charging station (CS) was carried out using a situational algorithm based on a Fuzzy expert system. The situational algorithm provides for moni... [more]

The performance of air-type PVT and BIPVT collectors has been extensively studied. As a system that generates heat and power, PVT collector testing has some particularities especially when using air as a heat recovery fluid and a building-integrated design (BIPVT). The electrical and thermal experimental performance of such collectors are currently being evaluated using in-house methods or PV and/or solar thermal collector standards. The use of a wide range of methods, testing conditions and experimental setups makes it difficult not only to compare the performance of different designs, but also to have confidence in the results obtained. This study evaluates the performance of an air-type BIPVT collector with in-channel perforated baffle plates for heat transfer enhancement designed for a building-integrated façade. As part of a joint research project between Korea and Canada, the proposed collector’s performance was evaluated through indoor (Canada) and outdoor experiments (Korea). L... [more]

Smart transformers are considered a crucial part of future smart grids as they will operate as the energy router and be able to control the power flows from and to the microgrids since they are placed in the border. A multi-port transformer can integrate different energy resources, loads and energy storage systems, optimizing the power flows between these elements. Combining both concepts, a multi-port smart transformer is obtained that is able to integrate efficiently distributed and renewable energy resources, electric vehicle chargers, prosumers and energy storage in both AC and DC microgrids. Nevertheless, the operation of these transformers, composed of several modules connected in series to the high-voltage grid is not easy, mainly due to the different power consumed or generated by each module. In this paper this issue is analyzed and different operation strategies for coordinating the series-connected modules at the input side are studied by simulation. The paper will expose ho... [more]

In the top submerged lance (TSL) smelting process, flow boiling may occur in the lance’s inner pipe due to the heat coming from the furnace when liquid fuel is adopted. In the current study, a numerical simulation was carried out by coupling the Eulerian two-fluid model with the improved RPI wall boiling model to investigate the subcooled n-heptane flow boiling in the inner pipe. The effects of inlet velocity and pipe wall emissivity on two-phase flow and heat transfer are elucidated. The results show that, for pipes with inlet velocity ranging from 0.3 m·s−1 to 1.0 m·s−1, an increase in inlet velocity leads to a lower void fraction near the outlet, as well as a lower average velocity and a lower average temperature of each phase. Meanwhile, the Onset of Nucleate Boiling (ONB) position approaches to the outlet, and the total pressure drop of the entire pipe reduces when the inlet velocity increases. However, the opposite trends appear when increasing the pipe wall emissivity. The maxim... [more]

Besides technological processes; logistics; and the use of petrol and light solvents, which are widely known as pollutants, the sources of BTEX hydrocarbon contributing to air pollution may also include other petroleum products and fuels that feature higher boiling points and that have not yet been associated with this issue. In this study, the contents of benzene; toluene; ethylbenzene; and o-, m-, and p-xylene were evaluated in 25 commercial samples of diesel oils; the gaseous phase in thermodynamic equilibrium with liquid diesel oil at 40 °C was then evaluated. Based on the experimental results, it was found that benzene concentration in the gaseous phase is five to more than fifteen times higher than the limits set by regulations for benzene concentration in the air at a work place (1.6 mg/m3) and cannot be compared with the limits set by regulations for annual average basal levels of benzene concentration in the air (5 µg/m3). The research revealed that diesel oil is a potential s... [more]

Data driven approaches are utilized for optimal sensor placement as well as for velocity prediction of wind turbine wakes. In this work, several methods are investigated for suitability in the clustering analysis and for predicting the time history of the flow field. The studies start by applying a proper orthogonal decomposition (POD) technique to extract the dynamics of the flow. This is followed by evaluations of different hyperparameters of the clustering and machine learning algorithms as well as their impacts on the prediction accuracy. Two test cases are considered: (1) the wake of a cylinder and (2) the wake of a rotating wind turbine rotor exposed to complex flow conditions. The training and test data for both cases are obtained from high fidelity CFD approaches. The studies reveal that the combination of a classification-based machine learning algorithm for optimal sensor placement and Bi-LSTM is sufficient for predicting periodic signals, but a more advanced technique is req... [more]

Battery energy systems are playing significant roles in smart homes, e.g., absorbing the uncertainty of solar energy from root-top photovoltaic, supplying energy during a power outage, and responding to dynamic electricity prices. For the safe and economic operation of batteries, an optimal battery-management system (BMS) is required. One of the most important features of a BMS is state-of-charge (SoC) estimation. This article presents a robust central-difference Kalman filter (CDKF) method for the SoC estimation of on-site lithium-ion batteries in smart homes. The state-space equations of the battery are derived based on the equivalent circuit model. The battery model includes two RC subnetworks to represent the fast and slow transient responses of the terminal voltage. Moreover, the model includes the nonlinear relationship between the open-circuit voltage (OCV) and SoC. The proposed robust CDKF method can accurately estimate the SoC in the presence of the time-varying model uncertai... [more]

Today, the growing Asia-Pacific population causes a dramatic growth in energy supply to meet energy demand. The rapid rise in energy demand is causing concern in the region. Thus, the present study scrutinizes the effect of energy policy involvement in steering-up renewable energy development by empirically assessing the role of policy instruments in encouraging residential-scale and commercial-scale photovoltaic (PV) systems. The analysis is performed using a fixed effects estimator on a selected range of policy approaches (market-pull policies and tax incentives) and a technology-push policy (capital grants) in selected Asia-Pacific countries between 1998 and 2015. The return on investment is estimated to measure the incentives of feed-in tariff (FIT) tariff policies for both residential-scale and commercial-scale PV systems. This study has shown the importance of a strategic combination between technology-push and market-pull policies as complementary to adopting technology and incr... [more]

The article presents a method of selecting an arch yielding support for preparatory workings driven in a hard coal seam. Particular attention was paid to discontinuous deformation in the form of a fault, which significantly contributes to the change of the excavation protection schemes. On the basis of the geometry of the machines and devices in the designed excavation, the support was selected, which was then checked for the ventilation criterion. In the next stage, analytical calculations were carried out using the determined spacing of the steel support in the fault zone and the area outside of it. Additionally, using the RS3 numerical software based on the finite element method, a rock mass model with a fault was built, through which the preparatory excavation passes. The aim of the research was to determine the total displacements occurring in the fault crossing zone for the excavation without support and with the use of steel arch yielding and with additional reinforcement in the... [more]

The aim of this study is to investigate the potential improvement of accident-tolerant fuels in pressurized water reactors for replacing existing reference zircaloy (Zr) fuel-cladding systems. Three main strategies for improving accident-tolerant fuels are investigated: enhancement of the present state-of-the-art zirconium fuel-cladding system to improve oxidation resistance, replacement of the current referenced fuel-cladding system material with an alternative high-performance oxidation-resistant cladding, and replacement of the current fuel with alternative fuel forms. This study focuses on a preliminary analysis of the neutronic behavior and properties of silicon carbide (SiC)-fuel and FeCrAl cladding systems, which provide a better safety margin as accident-tolerant fuel systems for pressurized water reactors. The typical physical behavior of both cladding systems is investigated to determine their general neutronic performance. The multiplication factor, thermal neutron flux spec... [more]

The income gap and global warming have always been topics of common concern to scholars worldwide. Internationally, there is no consensus yet about the impact of the income gap on carbon emissions, and there are few studies about that in China. To explore the effect of the income gap on carbon emissions at the provincial level in China, this paper first theoretically and qualitatively analyzes the non-linear impact of the income gap on carbon emissions. Then, the Gini coefficient of the resident income of different regions in China from 2010 to 2019 is calculated. Finally, a threshold regression model is used to quantitatively test the existence of a threshold effect between the income gap and carbon emission intensity in China. The threshold value is the per capita disposable income of residents. The results show that the income gap is positively related to carbon emission intensity in poor regions. In high-income areas, the widening income gap inhibits the increase in carbon emission... [more]

The RNG k-ε model turbulence model is used to carry out a CFD numerical simulation of the dual-flow channel pumping station. Through the model test, the accuracy of the numerical simulation of the dual-flow channel pump device is verified. Using the harmonic response analysis method, the water pressure fluctuating load calculated under different startup conditions under the design water level is applied to the pumping station. In this way, the dynamic response law of the pump station structure under the action of water pressure pulsation is studied. The calculation results show that the values of pressure pulsation in the drainage condition and the water diversion condition are relatively close, and the main difference is the difference in the water levels of the inlet and outlet water. Under different working conditions, the amplitude of the pumping station building basically shows the characteristics that the vertical amplitude is greater than the horizontal amplitude. The maximum dy... [more]

In this manuscript, we propose a single-phase UPC (universal power compensator) system to extensively tackle power quality issues (voltage and current) with an equal VAR (volt-ampere reactive) sharing approach between the series and shunt APF (active power filter) of a UPC system. The equal VAR sharing feature facilitates the series and shunt APF inverters to be of an equal rating. An SRF (synchronous reference frame)-based direct PA (power angle) calculation technique is implemented to realize equal VAR sharing between the APFs of the UPC. This PA estimation utilizes d and q axis current parameters derived for the reference signal generation of the shunt APF. An SRF-based method is highly useful for power estimations in distorted supply voltage conditions compared with other conventional methods, i.e., the PQ method. It comprises a reduced complexity and estimations with an easiness to retain two APF inverters of equal rating. A rigorous simulation analysis is performed with MATLAB/SI... [more]

Economic development is mainly dependent on fossil fuels. The massive use of fossil fuels has led to changes in the climate environment, in which the deterioration of air quality has affected people’s daily lives. This paper introduces the green growth level as a control variable to explore the connection between carbon dioxide emissions and the level of economic growth. It uses the EKC algorithm and VEC model to analyze Nanjing city’s data from 1993 to 2018. Given the data availability, the ARIMA algorithm was used to project carbon emissions for 2019−2025. It is found that the EKC curve of Nanjing City shows an N-shape, and the growth of economic level will cause the enhancement of carbon dioxide emissions. Carbon emissions will reach 7,592,140 tons in 2025. At present, we are in an essential stage of transition from N-shape to inverted U-shape, and this paper makes several recommendations based on the findings.

Biodiesel has been established as a promising alternative fuel to petroleum diesel. This study offers a promising energy conversion platform to valorise high acidity waste cooking oil (WCO) into biodiesel in a single-step reaction via supercritical methanol. Carbon dioxide (CO2) has been used as a co-solvent in the reaction with a catalytic effect to enhance the production of biodiesel. This work provides an in-depth assessment of the yield of four fatty acids methyl esters (FAME) from their correspondent triglycerides and fatty acids. The effects of four independent process variables, i.e., methanol to oil (M:O) molar ratio, temperature, pressure, and time, have been investigated using Response Surface Methodology (RSM). Four quadratic models have been developed between process variables and the yield of FAMEs. The statistical validation of the predicted models has been performed using analysis of variance (ANOVA). Numerical optimisation has been employed to predict the optimal condit... [more]

A continual increase in the influence of exogenic conditions on a company’s ability to sustain and develop and increasing complexity of the management processes correlated with the discovery of new dimensions of an enterprise, which determine its potential—these all lead to a growing interest in the search for the factors which might facilitate the elevation of the level of integrity of a business model of an enterprise/organisational and managerial system of an enterprise. Currently, it is absolutely necessary to perceive an enterprise not only in the terms of a rational economic system that, in its activity, concentrates on the generation of a positive financial result, and the creation of its value for the stockholders, but also as the system, at the same time, is meant to act responsibly in relation to its stakeholders, society and the market. The observation of successful enterprises shows clearly that the company values make up an element indispensable for the creation of effecti... [more]

During the load rejection transient process of the prototype pump turbine units, the pressure fluctuations of the entire flow passage change drastically due to the rapid closing of guide vanes. The extremely unsteady pressure distribution in the flow domains including the crown chamber and the band chamber may cause a strong vibration on the stationary structures of the unit and result in large dynamic stress on the head cover, stay ring and bottom ring. In this paper, the numerical fluid dynamic analysis of the entire flow passage of a reversible prototype pump turbine during load rejection was performed. The flow characteristics in the runner passage, crown chamber, band chamber, seal labyrinths and balance tubes are analysed. The corresponding unsteady flow-induced dynamic behaviour of the head cover, stay vanes and bottom ring was investigated in detail. The analysed results show that the total deformation of the inner edge of the head cover closed to the main shaft is larger than... [more]

The borehole drilling distance is short in soft and gas outburst-prone coal seams because of drill pipe jamming induced by cuttings accumulating in the borehole, hindering coal mine gas hazard prevention and utilization. A surface multi-hole (SMH) drill pipe composed of a bearing layer, fluid layer, and anti-sparking layer was proposed preliminarily, where several sieve holes were also set. To study the process of drilling cuttings in boreholes entering into the inner hole of an SMH drill pipe and its influencing factors, mechanical model analysis, CFD-DEM simulation, and a physical experiment were conducted. Our research results show the cutting entering region (CER) of the SMH drill pipe shrinks with the rotary speed, expands with the external extrusion force, and is offset with the sieve hole inclination angle. The drilling cuttings migrate and accumulate over time between the borehole wall and SMH drill pipe, which increases their compressive forces and induces increases in the mas... [more]

A two-stage desulfurization process including an abiotic filtration using cellular concrete waste (first stage) and an anoxic biotrickling filter filling with an inoculated expanded schist material (second stage) was investigated to remove H2S in mimic biogas with limited O2 amount (ranged from 0.5 to 0.8%). The two-stage process was able to satisfactorily remove H2S for all experimental conditions (RE > 97%; H2S concentration = 1500 mg m−3; total Empty Bed Residence Time (EBRT) = 200 s; removal capacity (RC) = 26 g m−3 h−1). Moreover, at a total EBRT = 360 s (i.e., 180 s for each stage), the H2S loading rate (LR) was almost treated by the bed of cellular concrete alone, indicating that abiotic filtration could be applied to satisfactorily remove H2S contained in the gas. According to the H2S concentration entering the biotrickling filter, the majority end-product was either elemental sulfur (S0) or sulfate (SO42−). Thus, the ability of the abiotic filter to remove a significant part o... [more]