Critical materials for infrastructure: local vs global properties

Previous research has revealed the uniqueness-facilitation effect in the multiple object tracking (MOT) task: simple distinct identities and surface features of moving targets could facilitate attentional tracking. By adapting compound stimuli, the present study investigated whether the global or local properties played the main role in the uniqueness-facilitation effect in the MOT task. The uniqueness of local properties, of global properties or of both local and global properties were considered. Observers’ tracking performance in alternative conditions were compared with that in the homogeneous condition wherein all stimuli have identical local and global properties. Results from two experiments suggest that the global properties played the key role in facilitating tracking. The distinctiveness of local properties can also facilitate tracking with global properties being homogeneous. However, when the stimuli’s global properties are distinct from each other—whether the local properties being unique or not—observers’ tracking performance can achieve the same level as that in the unitary-uniqueness condition wherein the moving objects were distinct unitary letters. These results revealed a global superiority effect in the MOT task. Finally, the facilitation effects of the global and local properties might depend on the stimulus sparsity. When the compound stimuli had fewer local elements, the uniqueness facilitation effect on tracking decreased.

Cellular systems are organized as a complex web of interactions among numerous macromolecules. Among the others, proteins are important since they play important role in virtually every biological process that occurs in the cell. Cellular systems are constantly challenged by fluctuations in the surrounding environment. In response, repertoire of the protein contents in the cell constantly alters, accordingly the interactions among them. Mathematically, these protein–protein interactions (PPIs) can be conceptualized in the form of graph or network for ease in analysis. A node in the graph represents protein and its link with other node is represented by edge. The local and global topological properties of the network reveal organization principles of underlying interactions among total proteins of an organism. The local properties specify importance of a particular protein in the network whereas global properties reflect their organization operational in the cell. Over the years, several graph theoretic and clustering techniques proposed for analysis of complex physical world have been applied to understand dynamic organization of the cellular networks. These methods promise to become more informative as the high quality PPI networks increase by orders of magnitude. This chapter provides an overview on various topological properties of networks and their significance in understanding biological systems.

Cluster-based wind turbine maintenance prioritization for a utility-scale wind farm

Global power consumption is rising, making it vital to look for other sources of energy to solve the impending power crisis. Using grid-synchronized electric vehicles (EVs) is likely to be one way to do this. The whole power system is impacted when several EVs are paired with the grid, leading to imbalances in supply and demand as well as voltage and frequency. We have integrated solar and wind energy in this integration to reduce these concerns. One of the developments in smart grid technology that permits energy exchange between the EV and the grid is vehicle to grid (V2G) technology. The hybrid energy source proposed by this project is used to charge EVs. Here, power from the PV panel, wind turbine, and AC generator is used to charge the EV battery. Any excess energy is then used to fuel the linear and non-linear demands of the subsequent home. A proportional-integral (PI) controller, which is recognized for its dependability and independence from the real system model, is used to maximize the DC voltage extracted from the photovoltaic (PV) panel. The DC voltage is improved overall by the Boost converter’s improved DC output. Concurrently, the system incorporates an AC generator to supply extra power to the grid. A three-phase Voltage Source Inverter (VSI) converts an improved output of the Boost conversion process used to convert the electricity from the PV panel into AC power. In order to assure safe current injection into the grid, harmonic components detected in the VSI output are rectified using an LC filter to ensure grid compatibility. In this research, the voltage for the EV battery is adjusted using a bidirectional converter. Electricity from EVs that are not in use may be sent back into the grid for additional purposes. Simulink and MATLAB 2021a are used to simulate and evaluate the proposed method.

Global critical materials markets: An agent-based modeling approach

The article is devoted to the determination of the development of domestic electric vehicle transport and electric vehicle infrastructure on the basis of such an economic and legal instrument as the post-war recovery program of Ukraine, taking into account EU approaches in the legal regulation of decarbonization of the transport sector. The European Commission adopted the Communiqué to the European Parliament, the European Council, the European Economic and Social Committee and the Committee of the Regions «Assistance and Reconstruction of Ukraine» on 18.05.2022, where the provision of funds for the post-war reconstruction of Ukraine is conditioned by our country’s compliance with current European policies and standards, one of which there is decarbonization. Therefore, Ukraine should carry out post-war reconstruction taking into account the experience and approaches outlined by the international acts of the EU. The National Council for the Recovery of Ukraine from the Consequences of the War, a consultative and advisory body under the President of Ukraine, proposed a draft Plan for the Recovery of Ukraine. Based on the analysis of the provisions of the project component of the Recovery Plan of Ukraine «Restoration and development of infrastructure». It was concluded that the project of the Recovery Plan of Ukraine and its component «Recovery and development of infrastructure» is an economic and legal instrument of a programmatic nature. It establishes a systematic approach to the more active use of electric vehicles and the development of electric charging stations. The plan defines short-term, medium-term and strategic tasks for the development of electric mobility infrastructure. The general program approaches defined in this act correspond to the directions established by the normative legal acts that were adopted to regulate the issues of environmentalization of the domestic transport sector before the war, as well as the general directions of the development of the charging infrastructure of electric vehicles, outlined by the international acts adopted in the EU. The disadvantage is that a complete transition to electric transport for the transportation of passengers on urban and suburban routes is foreseen in the medium term, which is an extremely limited period. In the Plan, it is expedient to use the objective indicators of the development of the system of electric filling stations, which are established in the domestic regulatory and technical acts. Also, the directions of the development of electric transport and the network of electric gas stations should be reflected in the programs of comprehensive restoration of the region, the territory of the territorial community.

Permanent Magnet Synchronous Motors (PMSMs) are prevalent today due to their advantages, including high efficiency and power. They are the primary motor in most Electric Vehicles (EVs), providing precise, rapid movements for industrial robots and CNC machines, and they act as generators in wind turbines. Therefore, identifying them and designing efficient controllers are crucial, resulting in higher performance and benefiting their capacities. According to the nonlinearities of the PMSM mathematical model and its sensitivity to external disturbances, designing a controller for this type of motor is challenging, and it degrades the performance of conventional linear controllers such as PI controllers. To address this problem, this paper evaluates the performance of an integrated control strategy that combines an advanced suboptimal tracker with an Extended Kalman Filter (EKF). The controller is based on a novel State-Dependent Riccati Equation (SDRE) technique that overcomes the limitations of traditional SDRE regulators by transforming the tracking problem into an equivalent regulation problem. Applying this unique formulation, the tracking of non-decaying reference trajectories will be possible using a discounted cost function, and controller gains are generated from a single Riccati equation. This methodology avoids the need to solve the complex Hamilton-Jacobi-Bellman equation. Concurrently, the EKF can estimate the unknown load torque online and is designed to reject disturbances proactively. Combining EKF and the novel SDRE method results in a nonlinear control structure that enhances tracking accuracy and system robustness.

To study the on grid wind turbine generator made in china, three types of horizontal axis three-blade wind turbine generator were researched. The design of wind turbine and the factors which influence the property of the wind wheel were studied. The mathematical model and operation principle of wind turbine with squirrel cage induction generator, doubly-fed induction generator and permanent magnet synchronous generator were studied. The operation conditions of the wind turbine generators in Dabancheng wind farm were investigated. The conclusion is that all the three types of wind turbine generators can be used well according the wind condition of the wind farm. The variable speed wind turbine with doubly-fed induction generator and with permanent megnet synchronous generator have less influence to the power system and they can recover the power generation easier while grid fault is cleared compared with the wind turbine with squrrel-cage induction generator.

Abstract. Nocturnal low-level jets (LLJs) are defined as relative maxima in the vertical profile of the horizontal wind speed at the top of the stable boundary layer. Such peaks constitute major power resources for wind turbines. However, a wind speed maximum implies a transition from positive wind shears below the peak to negative ones above. The effect that such a transition has on wind turbines has not been thoroughly studied.This research study employed a methodical approach to the study of negative wind shear's impacts on wind turbines. Up to now, the presence of negative shears inside the turbine's rotor in relation to the presence of positive shears has been largely ignored. A parameter has been proposed to quantify that presence in future studies of LLJ–wind-turbine interactions. Simulations were performed using the NREL aeroelastic simulator FAST code. Rather than using synthetic profiles to generate the wind data, all simulations were based on real data captured at the high frequency of 50 Hz, which allowed us to perform the analysis of a turbine's impacts with real-life, small scales of wind motions.It was found that the presence of negative wind shears at the height of the turbine's rotor appeared to exert a positive impact on reducing the motions of the nacelle and the tower in every direction, with oscillations reaching a minimum when negative shears covered the turbine swept area completely. Only the tower wobbling in the spanwise direction was amplified by the negative shears; however, this occurred at the tower's slower velocities and accelerations. The forces and moments were also reduced by the negative shears. The aforementioned impacts were less beneficial in the rotating parts, such as the blades and the shafts. Finally, the variance in power production was also reduced. These findings can be very important for the next generation of wind turbines as they reach deeper into LLJ's typical heights.The study demonstrated that the presence of negative shears is significant in reducing the loading on wind turbines. A major conclusion of this study is that the wind turbines of the future should probably be designed with the aim of reaching the top of the nightly boundary layer more often and therefore the altitudes where negative shears are more frequent. Doing so will help to reduce the positive shear's associated damage and to capture the significant LLJ energy.

Power demand is rising worldwide, forcing the search for an alternative source to solve the imminent power crisis, which is expected to be accomplished through the deployment of grid synchronized electric vehicles (EV). Wind and solar energy are incorporated into this integration to those concerns. One smart grid innovation that permits energy exchange between the EV and the grid is vehicle to grid (V2G) technology. For the purpose of charging EVs, this research proposes employing hybrid energy. Here, the neighboring household’s linear and non linear demands are powered by the excess electricity from the photovoltaics (PV) panel, wind turbine, and AC generator that is utilized to charge the EV battery. Because of its dependability and independence from the real system model, a proportional integral (PI) controller is used to maximize the DC voltage extracted from the PV panel. The improved DC voltage overall is a result of the SEPIC converter’s improved DC output. Concurrently, an AC generator is incorporated into the system to supply extra power to the grid. An artificial neural network (ANN) controller is used to convert the power generated by the PV panel’s Sepic conversion process into an improved output that is then converted to AC using a 3 phase Voltage Source Inverter (VSI). Harmonic components in the VSI output are corrected with an LC filter to ensure grid compatibility and safe current injection into the grid. This paper discusses the usage of a bidirectional converter to adjust the EV battery’s voltage. MATLAB 2021a / Simulink software is used to simulate and validate the proposed approach.

In this paper we study the relationships between local and global properties in networks of dynamical systems by focusing on two global properties, synchronization and peak-to-peak dynamics, and on two local properties, coherence of the components of the network and coupling strength. The analysis is restricted to networks of low-dimensional chaotic oscillators, i.e. oscillators which have peak-to-peak dynamics when they work in isolation. The results are obtained through simulation, first by considering pairs of coupled Lorenz, Rössler and Chua systems, and then by studying the behavior of spatially extended tritrophic food chains described by the Rosenzweig–MacArthur model. The conclusion is that synchronization and peak-to-peak dynamics are different aspects of the same collective behavior, which is easily obtained by enhancing local coupling and coherence. The importance of these findings is briefly discussed within the context of ecological modeling.

For many centuries to date, wind energy has been used as a source of power for a whole host of purposes. In early days it was used for sailing, irrigation, grain grinding, etc. At the onset of the 20th century, wind energy was put to work on a different use: power generation and electricity-generating wind turbines were produced. Wind turbines do convert the wind renewable energy into electricity, thus becoming a clean and sustainable power generation alternative. There is a large number and wide assortment of wind turbines which, over time, have evolved in its two key areas: capacity and efficiency. The evolution of wind turbines has been boosted thanks to the growing awareness on environmental issues which in turn stems from an equally growing concern over conventional fossil fuel energy sources. Furthermore, high oil prices and other financial incentives are also bearing their respective weights on the issue. Large scale wind turbines in the range 4 to 10 MW are now being developed and used for equipping large-scale wind farms worldwide. The power developed with wind generators depends on several factors with the noteworthy ones being the height above the ground level, the humidity rating and the geographic features of the area but the chief factor is the wind speed. Therefore, the first step in ascertaining the energy that can be produced and the effects of a wind farm on the overall electricity network calls for a thorough understanding of wind itself. There are different methods used in estimating the wind potential. This paper is aimed at presenting the impact of various methods and models used for extrapolating wind speed measurements and generate a relevant wind speed profile. The results are compared against the real life wind speed readings. Wind resource maps come as a plus factor.

The rotor blades are key components in wind turbine generators. A visual inspection of the laminated shells for delaminations, air pockets, missing/disoriented fabric etc. is in most cases also not possible due to the manufacturing process, so Non-destructive testing and evaluation (NDT & E) techniques for assessing the integrity of rotor blades structure are essential to both reduce manufacturing costs and out of service time of wind turbine generators due to maintenance. Nowadays, Infrared Thermal Wave Nondestructive Testing (Pulsed thermography) is commonly used for assessing composites. This research work utilizes Infrared Thermal Wave Nondestructive Testing system (EchoTherm, Thermal Wave Imaging, Inc.) to inspect a specimen with embedded defects (i.e. foreign matter and air inclusions) in different depth which is a part of rotor blades in wind turbine generators, we have successfully identified defects including foreign matter and air inclusions, and discovered a defective workmanship. The system software allows us to simultaneously view and analyze the results for an entire transition.

ABSTRACTThis paper describes an optimization‐based approach to reducing extreme structural loads during rapid or emergency shutdown of multi‐megawatt wind turbine generators. The load reduction problem is cast into an optimal control formulation, and a simple, low‐order model is developed in order for this optimization problem to be tractable in reasonable time using state‐of‐the‐art numerical methods. To handle the variations in wind speed and turbulence inherent to wind turbine operation as well as the presence of model mismatch, a real‐time optimization strategy based on fast sensitivity updates is also considered, whose online computational burden is limited to the repeated solution of quadratic programs that are designed offline. The low‐order model and both the open‐loop and closed‐loop optimal control strategies are validated against a high‐fidelity model in the simulation environment Bladed™ for an industrial 3 MW wind turbine. Under favorable shutdown scenarios, i.e. when the wind turbine is operating properly and the actuators and sensors are not faulty, large reductions of the first compressive peak and subsequent compressive/tensile peaks of the tower load pattern are obtained at various above‐rated wind speeds compared with normal pitch control shutdown. Extension to more challenging shutdown scenarios are also discussed. Copyright © 2013 John Wiley & Sons, Ltd.

The transport sector in Nigeria is a major contributor to greenhouse gas emissions and urban air pollution. This study investigates the contrasting trends in emissions from electric vehicles (EVs), hybrid-electric vehicles (HEV) and fossil fuel-powered vehicles in Nigeria. The objective of this paper is to explore the role of electric and hybrid vehicles as sustainable transportation options that contribute to emission reduction. It examines the environmental, economic, and technological implications of adopting these vehicles, with a specific focus on Nigeria. It also evaluates global best practices and how they can inform domestic policies and infrastructure development. Using recent data from the National Bureau of Statistics (NBS), International Energy Agency (IEA) and the World Bank, scholarly articles and industry sources, the study finds that emissions from EVs are declining, driven by increased adoption, government incentives, and rising public awareness of environmental issues and climate change mitigation. In contrast, emissions from fossil fuel vehicles continue to rise due to rapid growth in vehicle ownership, the prevalence of aging and inefficient vehicles, substandard fuel quality, and inadequate public transport infrastructure. The study concludes that while Nigeria’s efforts to promote EVs are yielding positive results, these gains risk being undermined unless systemic challenges in the broader transport sector are addressed. The paper recommends a comprehensive policy approach, including stronger EV incentives, improved fuel quality regulations, modern public transport investment and stricter emissions standards, to achieve sustained reductions in transport-related emissions. These findings contribute to the discourse on sustainable transportation pathways in developing economies.