More than half of the world’s population live in cities, and by 2050, it is expected that this proportion will reach almost 68%. These densely populated cities consume more than 75% of the world’s primary energy and are responsible for the emission of around 70% of anthropogenic carbon. Providing sustainable energy for the growing demand in cities requires multifaceted planning approach. In this study, we modeled the energy system of the Greater Montreal region to evaluate the impact of different environmental mitigation policies on the energy system of this region over a long-term period (2020−2050). In doing so, we have used the open-source optimization-based model called the Energy−Technology−Environment Model (ETEM). The ETEM is a long-term bottom−up energy model that provides insight into the best options for cities to procure energy, and satisfies useful demands while reducing carbon dioxide (CO2) emissions. Results show that, under a deep decarbonization scenario, the transporta... [more]

No systematic comparative study has been conducted on the factors controlling organic matter enrichment in the different depositional environments of the Lower Cambrian Qiongzhusi Formation in the western Middle Yangtze Block, leading to a large discrepancy in our understanding. Based on organic geochemical and elemental analyses of core, outcrop, rock, and mineral samples from the slope, deep-water shelf, and shallow-water shelf, in this study, comparative analysis of the organic matter content, sedimentological characteristics, and depositional paleoenvironments of the Lower Cambrian Qiongzhusi Formation in the western Middle Yangtze Block was conducted, and the main controlling factors and models of the organic matter enrichment were investigated. The results revealed that the organic matter enrichment in the Qiongzhusi Formation was jointly controlled by redox conditions, water restriction, upwelling currents, terrigenous inputs, and paleo-productivity, but the main factors control... [more]

The traction motor (TM) is an essential part of the high-speed train, the health condition of which determines the quality and safety of the vehicle. Hence, this study proposed a novel approach to diagnosing and predicting the TM stator interturn short-circuit fault (SISCF). Based on the Park vector (PV) of the stator current, this method could overcome the interference of current sensor errors, null shift, and motor frequency fluctuations in the actual conditions. More specifically, Park’s transformation was used to obtain the PV of the stator current. Then, the PV was fitted to obtain the elliptical trajectory and its parameters from which the negative sequence component of the stator current could be calculated. Finally, the SISCF diagnosis and prediction method were realized by the magnitude and trend of the negative current as well as the inclination of the trajectory ellipse. Furthermore, the performance of the proposed method was validated by a simulation model and a series of e... [more]

Tectonic interpretation is critical to a coal mine’s safe production, and fault interpretation is an essential component of seismic tectonic interpretation. With the increasing necessity for accuracy in fault interpretation in coal mines, it is increasingly challenging to achieve greater accuracy only through traditional fault interpretation. The convolutional neural network (CNN) is a machine learning method established in recent years and it has been widely applied in coal mine fault interpretation because of its powerful feature-learning and classification capabilities. To improve the accuracy and efficiency of fault interpretation in coal mines, an automatic seismic fault identification method based on the convolutional neural network has been developed. Taking a mining area in eastern Yunnan province as an example, the CNN model realized automatic identification of faults with eight seismic attributes as feature inputs, and the model-training parameters were optimized and compared... [more]

A pneumatic cylinder system is believed to be extremely nonlinear and sensitive to nonlinearities, which makes it challenging to establish precise position control of the actuator. The current research is aimed at reducing the overshoot in the response of a double-acting pneumatic actuator, namely, the IPA positioning system’s reaction time. The pneumatic system was modeled using an autoregressive with exogenous input (ARX) model structure, and the control strategy was implemented using a fuzzy fractional order proportional integral derivative (fuzzy FOPID) employing the particle swarm optimization (PSO) algorithm. This approach was used to determine the optimal controller parameters. A comparison study has been conducted to prove the advantages of utilizing a PSO fuzzy FOPID controller over PSO fuzzy PID. The controller tuning algorithm was validated and tested using a pneumatic actuator system in both simulation and real environments. From the standpoint of time-domain performance me... [more]

Load and supply parameters may be uncertain in microgrids (MGs) due for instance to the intermittent nature of renewable energy sources among others. Guaranteeing reliable and stable MGs despite parameter uncertainties is crucial for their correct operation. Their stability and dynamical features are directly related to the controllers’ parameters and power-sharing coefficients. Hence, to maintain power good quality within the desirable range of system parameters and to have a satisfactory response to sudden load changes, careful selection of the controllers and power-sharing coefficients are necessary. In this paper, a simple design approach for the optimal design of controllers’ parameters is presented in an islanded MG. To that aim, an optimization problem is formulated based on a small-signal state-space model and solved by three different optimization techniques including particle swarm optimization (PSO), genetic algorithm (GA), and a proposed approach based on the combination of... [more]

Increasing awareness of climate change has induced demand for action most notably. As public demand for action on climate change increases, conversion to energy sources with lower greenhouse gas (GHG) intensity will accelerate. Experience during the COVID-19 pandemic provided insight into how atmospheric conditions will respond to lower GHG emissions. A low-carbon future will require decarbonization of the energy supply mix for electrical production and industrial processes. Coal demand likely will decrease more rapidly than other fossil energy sources, replaced by natural gas and renewable energy sources that have lower GHG intensity and that will be available readily and economically. This decline will accelerate as China focuses on its carbon neutrality goals, the U.S. re-engages in the Paris Agreement, and India moves to a lower carbon future. However, perturbations in the decline will inevitably occur in response to global issues (e.g., pandemic, military conflict). Carbon capture... [more]

The thermal comfort of an enclosed room with air conditioner and air-distribution duct coupling can be studied, and the parameters of a split-fiber air conditioner can be optimized on the basis of studying the thermal comfort of various parts of the human body. In this paper, a room model with a distributed air conditioner was proposed. First, the rationality of the three thermal comfort characterization models of predict mean vote (PMV), predicted percentage of dissatisfied (PPD), and percentage of dissatisfied (PD) were verified through experiments and simulations. Then, the temperature and thermal comfort of various parts of the human body were explored when the air-distribution duct had different openings and different positions of the air outlet. The simulation results showed that compared with other situations, when the split-fiber air conditioner had three rows of holes (5-o’clock, 6-o’clock, 7-o’clock) and the air outlet was located in the middle of the right wall of the human... [more]

Demand on the energy sector has increased significantly due to the incredible evolution of the industry and urbanization. Photovoltaic (PV) technology is rapidly evolving to meet the demands of people in the United Arab Emirates (UAE) by generating more electricity. The UAE has demonstrated that it has the world’s highest rates of sun exposure, indicating a significant efficiency in solar energy development. This might be a way to cut down on fossil fuel consumption and greenhouse gas emissions even further. In this review, we discuss five major aspects of solar energy utilization and projects within the framework of the UAE starting with (i) recent advances in solar scenario and development trends, (ii) electricity production, consumption, and tariffs, (iii) focus on various key aspects of photovoltaic solar installation projects inside the Dubai, Abu Dhabi emirates and other smaller projects in the UAE, (iv) different solar projects outside the UAE, and (v) the solar energy industry,... [more]

The rise of carbon dioxide (CO2) levels in the atmosphere emphasises the need for improving the current carbon capture and storage (CCS) technology. A conventional absorption method that utilises amine-based solvent is known to cause corrosion to process equipment. The solvent is easily degraded and has high energy requirement for regeneration. Amino acids are suitable candidates to replace traditional alkanolamines attributed to their identical amino functional group. In addition, amino acid salt is a green material due to its extremely low toxicity, low volatility, less corrosive, and high efficiency to capture CO2. Previous studies have shown promising results in CO2 capture using amino acids salts solutions and amino acid ionic liquids. Currently, amino acid solvents are also utilised to enhance the adsorption capacity of solid sorbents. This systematic review is the first to summarise the currently available amino acid-based adsorbents for CO2 capture using PRISMA method. Physical... [more]

High-order harmonic resonance is a key issue in the traction power supply systems (TPSS) of electric railways for safe operation. The effective evaluation of the resonance frequency is critical for taking measures to suppress harmonic resonance. In this paper, the influence of the distributed parameters of traction networks on resonance frequencies based on accurate calculation is proposed. The quantitative assessments of the distributed impedance and admittance are investigated. Furthermore, the theoretical calculation is directly verified using field tests at a high voltage level equal to 25 kV. The results show that the resonance frequencies of the TPSS are mainly affected by the distributed parameters, including the self-admittance and self-impedance of the contact wires, and the self-admittance of the positive feeders. In addition, the admittance connected in parallel has a greater effect than the series-connected impedance. The calculation method is also adapted to TPSS connected... [more]

The design of a fully superconducting wind power generator is influenced by several factors. Among them, a low number of pole pairs is desirable to achieve low AC losses in the superconducting stator winding, which greatly influences the cooling system design and, consecutively, the efficiency of the entire wind power plant. However, it has been identified that a low number of pole pairs in a superconducting generator tends to greatly increase its output voltage, which in turn creates challenging conditions for the necessary power electronic converter. This study highlights the interdependencies between the design of a fully superconducting 10 MW wind power generator and the corresponding design of its power electronic converter.

Aiming to solve the problem that the residual life of defective elbows is difficult to predict and the prediction accuracy of a traditional extreme learning machine (ELM) is unsatisfactory, a genetic algorithm optimization neural network extreme learning machine method (GA-ELM) that can effectively predict erosion rate and residual life is proposed. In this method, the input weight and hidden layer node threshold of the hidden layer node is mapped to GA, and the input weight and threshold of the ELM network error is selected by GA, which improves the generalization performance of the ELM. Firstly, the effects of solid particle velocity, particle size, and mass flow rate on the erosion of elbow are studied, and the erosion rates under the conditions of point erosion defect, groove defect, and double groove erosion defect are calculated. On this basis, the optimized GA-ELM network model is used to predict the residual life of the pipelines and then compared with the traditional ELM netwo... [more]

Low salinity water injection (LSWI) is an emerging way to improve waterflood performance through chemical processes. The presence of clay minerals is one of the required parameters to successfully implement LSWI in sandstone formations. The ability of clays to exchange the cations, represented by cation exchange capacity (CEC), leads to oil detachment from the rock surface and changes the formation wettability toward water-wet. There are still limited studies that discuss the implementation of specific CEC models in the field-scale LSWI reservoir simulation. This paper attempts to propose an improved method of clay-induced rock typing that can be representatively implemented for field-scale reservoir simulation. The scope of this study is limited to a sandstone reservoir from an oil field in Indonesia. The oil is considered light, and the reservoir contains main clay minerals, including kaolinite and illite, and a trace of chlorite was also found from the XRD evaluation. CEC can be der... [more]

Strong heterogeneity, low matrix permeability, and complex oil−water interaction make the fluid flow in carbonate rocks extremely complicated. In this study, we quantitatively characterize and simulate single-phase and multiphase flows with multiscale pore−vug−fracture structures involved in the carbonate reservoir developments. The main studies and conclusions include: (i) The CT technology is utilized to characterize the pores, fractures, and vugs of carbonate cores at multiple scales. It is found that even if the CT resolution reaches 0.5 μm, the pores of the core are still unconnected as a network, indicating that the carbonate matrix is particularly tight. The existence of fractures can increase the effective permeability, and even poorly connected fractures can significantly increase the permeability because it reduces the flow distance through the less permeable matrix. (ii) A numerical model of low-porosity strongly heterogeneous carbonate rocks was constructed based on digital... [more]

Heat recovery systems based on thermoelectric micro-generators (µ-TEGs) can play a significant role in the development of wireless, energetically autonomous electronics. However, to date, the power density recovered for low temperature differences using µ-TEGs is limited to a few micro-watts or less, which is still insufficient to power a wide-range of wireless devices. To develop more efficient µ-TEGs, material, device and system requirements must be considered simultaneously. In this study, an innovative design of an in-plane µ-TEG integrating bismuth telluride forming sinusoidal-shaped trenches is reported. Using 3D numerical modelling, the influence of boundary conditions, parasitic effects (electrical and thermal contact resistances), and transport properties of thermoelectric materials on the output power of these µ-TEGs are investigated in detail for a small temperature difference of 5 K between the hot and cold sources. Compared to wavy-shaped trenches, this novel shape enables... [more]

Smart Float is a new multi-modal underwater vehicle, a tool for ocean observation and detection, whose performance is limited by its underwater voyage distance and endurance like most underwater vehicles. The utilization of marine energy provides an ideal way to overcome these limitations. In this paper, an external ocean thermal energy power generation module is developed for Smart Float, which can be used for multiple times of energy storage and power generation and is expected to be further applied to small and medium-sized underwater vehicles. The integration of the proposed device will cause changes in the counterweight characteristic, hydrodynamic characteristic, and heat transfer characteristic of the vehicle, which are deeply analyzed in this study, and adaptive modification solutions are proposed according to the analysis results. Finally, a prototype of Smart Float integrating the proposed device was deployed in the South China Sea to perform a sea trial, to test its performa... [more]

Although interest in the use of membranes for the concentration of microalgal biomass has steadily been growing, little is known regarding the phenomena of membrane fouling. In addition, more attention has been given to polymeric membranes compared to ceramic membranes, which have a longer life that is associated with a higher resistance to aggressive chemical cleaning. In this study, microfiltration (MF) and ultrafiltration (UF) of two microalgae species, Chlorella vulgaris and Monoraphidium contortum, were carried out using tubular crossflow ceramic membranes. Permeate flux was measured, resistance was calculated, and dissolved organic carbon (DOC) was determined. The flux reduction during the first 10 min of filtration was higher for MF than UF (>70% and <50%), and steady-state permeate fluxes were <5% (for MF) and 80%) than for MF (<66%) and DOC concentrations (mg C L−1) in permeates following MF and UF were about five and two, respectively. In conclusion, we demonstrated:... [more]

The ‘second phase’ of the energy transition involves large-scale rollout of renewables, raising wider questions about arrangements for the management and ownership of such resources and how costs and benefits should be distributed. Ideas and practices such as ‘community energy’ and ‘prosumption’ capture the potential for more decentralised systems of ownership and control inherent in renewable energy technologies. However, until now, ownership and control of the key biophysical resources (e.g., wind, wave, solar, geothermal) underpinning the transition have received surprisingly little attention, given the potential for wealth creation and issues of justice that underpin their use. This paper explores this issue using the idea of ‘wind rights’, which highlights the numerous social actors who have rights or claims to use and benefit from wind resources. Key among these are landowners who are silently enclosing the ‘windy commons’ to extract ‘wind rents’ from monopoly property rights. Th... [more]

The European Union is aiming at reaching greenhouse gas (GHG) emission neutrality in 2050. Austria’s current greenhouse gas emissions are 80 million t/year. Renewable Energy (REN) contributes 32% to Austria’s total energy consumption. To decarbonize energy consumption, a substantial increase in energy generation from renewable energy is required. This increase will add to the seasonality of energy supply and amplifies the seasonality in energy demand. In this paper, the seasonality of energy supply and demand in a Net-Zero Scenario are analyzed for Austria and requirements for hydrogen storage derived. We looked into the potential usage of hydrogen in Austria and the economics of hydrogen generation and technology and market developments to assess the Levelized Cost of Hydrogen (LCOH). Then, we cover the energy consumption in Austria followed by the REN potential. The results show that incremental potential of up to 140 TWh for hydropower, photovoltaic (PV), and wind exists in Austria.... [more]

According to the structural and heat transfer characteristics of soil heat storage, a novel layered slice algorithm is proposed to realize the rapid and accurate solution to the problem. The heat transfer process between the double U-tube heat exchanger and the surrounding soil is taken as an example to analyze its solving performance. The study finds that the layered slice algorithm has higher simulation precision and faster solving speed. Its maximum relative error of temperature is only 0.19%. Compared with the traditional 3D simulation algorithm, it can accelerate about 2.2~2.56 times. At the same time, the layered slice algorithm has an excellent parallel characteristic. Its maximum parallel speedup ratio is more than twice that of the traditional 3D algorithm. Due to the superior solving performance, the proposed algorithm can help the optimization design of the buried-tube heat exchangers.

Unbalanced load condition is one of the major issues of all commercial, industrial and residential sectors. Unbalanced load means that, when different loads are distributed on a three-phase four-wire system, unequal currents pass through the three phases. Due to it, a heavy current flows in the neutral wire, which not only adds the losses, but also puts constraints on three phases’ loads. In this paper, we have presented a practical approach for load balancing. First, we have considered the existing three-phase load system where the supply is a three-phase unbalanced supply. Before balancing the load, it is necessary to compensate the current in neutral wire. A nature-inspired moth−flame optimization (MFO) algorithm is used to propose a scheme for balancing of current in neutral wire. The information of a distributed single-phase load was used to balance the currents in a three-phase system. The feeder phase and load profiles of each single-phase load are used to reconfigure the networ... [more]

Non-renewable-resource consumption and global greenhouse-gas (GHG) emissions are critical issues that pose a significant threat to sustainable development. Solar energy is a promising source to generate renewable energy and an appealing alternative electricity source for households. The primary goal of this research is to detect the rooftops that have no solar photovoltaic (PV) system deployed on them but that receive moderate to high solar-energy radiation using the Geographic Information System (GIS) and deep-learning techniques. Although various studies have been conducted on this subject, not many addressed these two issues simultaneously at a residential level. Identifying the installed solar PV systems in a large area can be expensive and time-consuming work if performed manually. Therefore, the deep-learning algorithm is an emerging alternative method to detect objects using aerial images. We employed the Single-Shot-Detector (SSD) model with the backbone of residual neural netw... [more]

Hydrothermal treatment (HTT) offers the potential to upgrade low-value biomass such as digestate (DG) or forest residue (FR) by producing solids and liquids for material use or energetic utilization. In this study, microwave-assisted HTT experiments with DG and FR as feedstocks were executed at different temperatures (130, 150, 170 °C) and with different holding times (30, 60, 90 min) to determine the influences on product properties (ash and elemental concentrations, calorific values and chemical compounds). In general, DG and FR reacted differently to HTT. For the DG solids, for instance, the ash concentration was reduced to 8.68%DM at 130 °C (initially 27.67%DM), and the higher heating value increased from 16.55 MJ/kgDM to 20.82 MJ/kgDM at 170 °C, while the FR solids were affected only marginally. Elements with importance for emissions in combustion were leached out in both HTT solids. The DG and FR liquids contained different chemical compounds, and the temperature or holding time... [more]

This paper proposes the distributed coordination of inverter-based resources, to optimize the operational cost of a microgrid system. The microgrid is considered a multiagent system, which includes a distributed generator agent and energy storage system agent. A communication network is utilized to exchange information among agents. The issue of communication failures is addressed in the proposed strategy, to ensure the stable operation of the control system. A two-level hierarchical cooperative optimization system is proposed in this paper for distributed economic dispatch. The primary controller is responsible for the frequency and voltage regulations, and the secondary controller is implemented in a diffusion-based distributed control scheme, for optimal microgrid management. The proposed control strategy consistently maintains the optimal operation and frequency, even in the event of communication failures. A five-node multiagent system including a dispatchable agent is considered.... [more]