Local Load Research Articles

Investigation on implementing the swarm nano grid system for effective utilization of solar-powered agro-industries

The agro-industry is the backbone of the global economy, even in the twenty-first century. The agro-industry would not be what it is now without irrigation. The production and use of renewable energy in this sector of the agricultural economy have also expanded rapidly in recent years. Base-load power production and conversions dominate the literature. This research examines user concerns. The swarm nano grid system fixes this. The pulse width modulation (PWM) sinusoidal inverter converted stable DC power from the bidirectional DC-DC converter into sinusoidal AC voltage for the irrigation pump induction motor. Solar panels, batteries, and converters are costly, but they pay off. The nano grid distributes excess power generated during low demand to local loads. This technique works well when the load can be disconnected from the power grid. MATLAB is used to keep an eye on the reliability and efficiency of the induction motor. In the first simulation, solar power generation is modeled using the MATLAB Simulink software in two distinct modes. A PWM sinusoidal inverter that is driven by solar energy is what provides power to the 5.67 kW induction submersible motor. The simulation result provides a conceptual model of how induction motors powered by renewable energy sources function in practice.

Numerical and Experimental Evaluation of Structured Material for Use in Multiscale Topology Optimization

Multiscale topology optimization is a powerful tool for engineers seeking a design with minimum weight and maximum stiffness, using a structured material in the form of a lattice structure. Furthermore, the current trend is to combine multiple lattice topologies in one component to achieve the best possible response to local loading conditions while minimizing weight. Therefore, herein, a numerical and experimental evaluation by compression tests in two directions is performed for six basic lattice topologies and two hypotheses are tested. The first hypothesis states that an additional weight saving of more than 30% can be achieved by a better choice of lattice topology. The second hypothesis is based on the manufacturing limitations of the laser powder bed fusion technology and the assumption that a favorable loading direction parallel to the building direction exists. The first hypothesis is only confirmed for loading in the direction parallel to the building direction and the second only for two lattice topologies. When both hypotheses are combined, the additional weight reduction of the multiscale topology optimization result is 44.5% according to the numerical results and 32.7% according to the experimental verification.

An optimal sizing framework of a microgrid system with hydrogen storage considering component availability and system scalability by a novel approach based on quantum theory

This paper introduces an innovative framework for optimizing a hybrid photovoltaic-wind system with integrated hydrogen storage, taking into account component availability and system scalability. The primary objective is to minimize the total net present cost (TNPC) while enhancing system reliability based on the Loss of Power Supply probability (LPSP). The decision variables include the determination of the number of photovoltaic (PV) panels, wind turbines (WTs), hydrogen storage mass, fuel cell capacity, electrolyzer capacity, and inverter capacity. To achieve this optimization, the Quantum Beluga Whale Optimization (QBWO) algorithm is employed, which is an improved version of the Beluga Whale Optimization (BWO) algorithm. QBWO overcomes some limitations of BWO by incorporating principles from quantum theory and addressing challenges related to the scarcity of population diversity and stagnation in local optima. Simulations were conducted for scenarios involving WT/FC, PV/FC, and PV/WT/FC systems. The results indicate that within a microgrid context, the PV/WT/FC configuration proves to be the most cost-effective approach for supplying local loads. Under certain conditions, it achieved the best TNPC with 0.8176 M$, Levelized Cost of Energy (LCOE) with 0.264 $/kWh, and LPSP with 0.04687. However, considering components availability and system scalability changes indicate a significant effect on the system cost and reliability. Overall, this framework provides a precise method for designing energy systems, considering factors such as electricity generation costs and reliability enhancements in the face of uncertainties. QBWO outperforms original BWO, Particle Swarm Optimization (PSO), and Crow Search Algorithm (CSA) by achieving lower design costs and improved reliability. This study contributes to developing environmentally friendly electrification plans and provides valuable insights for power investments in energy-deprived Southwest Morocco.

Large eddy simulation of wind pressures on a 600-m-high skyscraper and comparison with field measurements during super typhoon mangkhut

Super Typhoon Mangkhut struck the coastal cities in Southeast China on September 16, 2018, destroying many glass curtain walls of tall buildings. It calls for more investigations of the wind loads on tall buildings during strong tropical cyclones to reduce building damages. Following the field measurements of wind effects on a 600-m-high skyscraper in Shenzhen, China, during Super Typhoon Mangkhut, this study aims to reproduce the wind effects on the supertall building during Mangkhut by large eddy simulation (LES). A wide range of surrounding buildings from the target supertall building (within a radius of 5 km) is explicitly constructed for the LES. The wind profiles obtained from a 356-m-high meteorological tower in Shenzhen and those given in the local design load code are used to set the inflow conditions in the LES. The wind pressures on the supertall building simulated by the LES and monitored by the field measurements are compared and analysed, including their mean, root mean square, peak, probability density function, power spectral density, and correlation. This combined study of numerical simulation and field measurement is an impetus to promote the role of computational fluid dynamics in predictions of the wind effects on high-rise buildings under extreme wind conditions.

Dynamic responses of cylindrical lithium-ion battery under localized impact loading

Engineering problems, such as fire and explosion caused by mechanical damage, have restricted the further development of lithium-ion batteries (LIBs). The paper aims to present an effective method for studying the impact responses of cylindrical LIBs under localized impact loadings. An impact model in which the cell is simplified to a beam is developed considering the interaction between bending and stretching. The membrane factor (fn ) of the beam with a circular cross-section is introduced, and then the motion control equations for the cell with large deformation are derived. The accuracy of the theoretical method is verified based on the results from the mass block impact experiment and finite element simulation. A method for cell failure detection is established based on the force-displacement-voltage response from the impact experiment. It is shown that higher impact velocities and smaller punch widths increase cell deformation. Moreover, a larger punch mass results in greater displacement when the impact energy remains unchanged, and the strengthening tendency increases with the punch width. The research will provide theoretical guidance for the safety assessment and dynamic optimization design of LIBs.

Investigating electromagnetic acoustic emission signals denoising for alloy materials non-destructive detecting: a CRQA method

Aiming at the problem that signals collected from local electromagnetic loading operations are usually mixed with background noises (especially white noise), this paper proposed an electromagnetic acoustic emission signal denoising technology based on cross recurrence quantification analysis (CRQA). Firstly, the decomposition layer and penalty factor of variational mode decomposition (VMD) are set by experience or optimization algorithm, and then the original signal is decomposed. Secondly, the main components are selected by the CRQA algorithm, and the electromagnetic acoustic emission signal after denoising is obtained by superposition reconstruction. The simulation and experimental results show that when 5dB noise is added, CRQA can effectively remove the background noises in electromagnetic acoustic emission signals compared to the correlation coefficient algorithm, and it can assist in realizing the high-precision non-destructive testing of alloy materials.

Investigating electromagnetic acoustic emission signals denoising for alloy materials non-destructive detecting: a CRQA method

Aiming at the problem that signals collected from local electromagnetic loading operations are usually mixed with background noises (especially white noise), this paper proposed an electromagnetic acoustic emission signal denoising technology based on cross recurrence quantification analysis (CRQA). Firstly, the decomposition layer and penalty factor of variational mode decomposition (VMD) are set by experience or optimization algorithm, and then the original signal is decomposed. Secondly, the main components are selected by the CRQA algorithm, and the electromagnetic acoustic emission signal after denoising is obtained by superposition reconstruction. The simulation and experimental results show that when 5dB noise is added, CRQA can effectively remove the background noises in electromagnetic acoustic emission signals compared to the correlation coefficient algorithm, and it can assist in realizing the high-precision non-destructive testing of alloy materials.

The influence of lateral pressure on ultimate strength of ship structure

ABSTRACT The lateral pressure influences the ultimate strength of double-bottom structure. In the midship section of bulk carrier, upward bottom local loads typically exceed downward loads, resulting in increased longitudinal thrust in the outer bottom plating and a reduction in the ultimate strength of the hull girder during hogging conditions. In the present research, the typical stiffened plate and double bottom structures of the Kamsarmax type bulk carrier are taken as the research objects. The nonlinear finite element method is considered to analyze the collapse behaviour of the stiffened plate and double-bottom structure under the longitudinal thrust/bending and lateral pressure, respectively. The influence of lateral pressure on buckling modes, stress distribution, collapse mode and ultimate strength is systematically demonstrated and analyzed. This research contributes significantly to the safety design of hull structures.

Interactions between trade wind clouds and local forcings over the Great Barrier Reef: a case study using convection-permitting simulations

Abstract. Trade wind clouds are ubiquitous across the subtropical oceans, including the Great Barrier Reef (GBR), playing an important role in modulating the regional energy budget. These shallow clouds, however, are by their nature sensitive to perturbations in both their thermodynamic environment and microphysical background. In this study, we employ the Weather Research and Forecasting (WRF) model with a convection-permitting configuration at 1 km resolution to examine the sensitivity of the trade wind clouds to different local forcings over the GBR. A range of local forcings including coastal topography, sea surface temperature (SST), and local aerosol loading is examined. This study shows a strong response of cloud fraction and accumulated precipitation to orographic forcing both over the mountains and upwind over the GBR. Orographic lifting, low-level convergence, and lower troposphere stability are found to be crucial in explaining the cloud and precipitation features over the coastal mountains downwind of the GBR. However, clouds over the upwind ocean are more strongly constrained by the trade wind inversion, whose properties are, in part, regulated by the coastal topography. On the scales considered in this study, the warm-cloud fraction and the ensuant precipitation over the GBR show only a small response to the local SST forcing, with this response being tied to the surface flux and lower troposphere stability. Cloud microphysical properties, including cloud droplet number concentration, liquid water path, and precipitation, are sensitive to the changes in atmospheric aerosol population over the GBR. While cloud fraction shows little responses, a slight deepening of the simulated clouds is evident over the upwind region in correspondence to the increased aerosol number concentration. A downwind effect of aerosol loading on simulated cloud and precipitation properties is further noted.

Active Planning for Virtual Microgrids with Demand-Side and Distributed Energy Resources

In this paper, the notion of a cohesive and self-sufficient grid is proposed. Based on a cohesive and self-sufficient virtual microgrid, an active distribution network is optimally planned, and an optimal configuration of demand-side resources, distributed generations, and energy storage systems are generated. To cope with stochastic uncertainty from forecast error in wind speed and load, flexibility reserves are needed. In this paper, the supply relation between flexibility and uncertainty is quantified and integrated in an innovative index which is defined as cohesion. The optimization objectives are a minimized operational cost and system net-ability cohesion as well as self-sufficiency, which is defined as the abilities both to supply local load and to deal with potential uncertainty. After testing the optimal configuration in the PG&E 69 bus system, it is found that with a more cohesive VM partition, the self-sufficiency of VMs is also increased. Also, a case study on uncertainty-caused system imbalance is carried out to show how flexibility resources are utilized in real-time operational balance.

Injury Risk Functions for the Midsized Male Wrist and Elbow as a Result of Behind Shield Blunt Trauma.

Ballistic shields protect users from a variety of threats, including projectiles. Shield back-face deformation (BFD) is the result of the shield deflecting or absorbing a projectile and deforming toward the user. Back-face deformation can result in localized blunt loading to the upper extremity, where the shield is supported by the user. Two vulnerable locations along the upper extremity were investigated-the wrist and elbow-on eight postmortem human subjects (PMHS) using a pneumatic impacting apparatus for investigating the fracture threshold as a result of behind shield blunt trauma (BSBT). Impacting parameters were established by subjecting an augmented WorldSID anthropomorphic test device (ATD) positioned behind a ballistic shield to ballistic impacts. These data were used to form the impact parameters applied to PMHS, where the wrist most frequently fractured at the distal radius and the elbow most frequently fractured at the radial head. The fracture threshold for the wrist was 5663±1386 N (mean±standard deviation), higher than the elbow at 4765±894 N (though not significantly, p = 0.15). The failure impact velocity for wrist impacts was 17.7±2.1 m/s, while for the elbow, the failure impact velocity was 19.5±0.9 m/s. An approximate 10% risk of fracture threshold was identified on the modified WorldSID ATD (no flesh analogue included) to inform future protective standards.

Improvement of Voltage profile by Integrating Renewable Generation Units at weak bus locations of the System

The Grid consists of higher rating sources and transmission system that supports local loads. The grid operates at voltages in the range of 66kV-132kV and transmits power in MW to smaller or longer distance locations. Due to higher rating power system the power quality issues are also more. For our consideration an IEEE 14 bus interconnected system is represented as grid operating at higher rated values. The weak bus of the interconnected system is determined by Fast voltage stability index (FVSI) and load flow analysis using Newton-Raphson method available in MATLAB software. The weak buses are integrated with renewable power generation units like PV plant and wind farm improving the bus characteristics. This paper presents a comparative analysis with and without the RGUs in the system. Improvisation of the parameters like power loss, reduced conventional power consumption, power factor and voltage magnitudes are validated through time domain simulations.

Micromechanical modeling of discontinuous long fiber reinforced composites

The performance of discontinuous fiber composites is intricately linked to the microstructure of the composite material. Therefore, micromechanics prove valuable for the analysis and design of these materials. Two micromechanics theories, the high fidelity generalized method of cells and Carrera Unified Formulation, are used to model a repeating unit cell (RUC) of the Tailorable Universal Feedstock for Forming, a highly aligned discontinuous fiber carbon fiber composite system. The models are evaluated for their ability to predict the effective properties and local stress fields within the RUC. The stress fields between the fiber ends and the fiber-matrix interfacial stresses are of particular interest. The models are used to predict the effective properties of single fiber and multiple fiber RUCs with varying fiber-to-fiber end gap lengths, as well as the local stresses in the fiber and matrix. Both models produced similar results and demonstrated that they could capture the complex local load transfer. A statistical study is also undertaken to understand the effect of gap clustering on the effective properties and local stress fields.

Smart investment framework for energy resilience: A case study of a campus microgrid research facility

Energy resilience is a vital consideration for ensuring the survivability of modern infrastructure systems. Achieving 100% resilience, however, is often impractical and economically burdensome. In this paper, we propose a smart investment framework that enables decision-makers to determine optimal investments in energy resilience based on available resources and desired levels of resilience. To illustrate the effectiveness of this framework, we present a case study of a campus microgrid research and testing facility. Using a real-time simulation approach conducted with Typhoon Hardware In Loop (HIL), we evaluate the performance of the microgrid system over 24 hours following 4 historically significant hurricanes that have affected Louisiana in the past few years. The microgrid is designed to power local loads during outages, providing an effective solution for enhancing energy resilience. Real solar data collected from our 1.1 Megawatt (MW) solar facility on the University of Louisiana at Lafayette campus is integrated into the simulation, enabling a realistic evaluation of the system’s performance under hurricane-induced disruptions. By employing the proposed smart investment framework, decision-makers can better identify and address resilience challenges. The framework facilitates informed investment decisions by considering available resources and aligning them with the desired level of resilience. This approach avoids over-investment in unnecessary redundancy while ensuring critical systems are adequately protected. Our research contributes to the field by demonstrating the practicality and benefits of a smart investment framework for energy resilience in a real-world scenario. The case study of the campus microgrid research facility provides valuable insights for decision-makers in similar contexts, highlighting the potential of this framework to guide resilient energy infrastructure planning and investment strategies.

Experimentally Dissociating the Acute Mechanisms of Endplate Fracture Lesions and Schmorl's node Injuries Using a Porcine Cervical Spine Model.

In vitro biomechanical study. This study evaluated the influence of localized trabecular bone strength deficits and loading rate as determinants of Schmorl's node and fracture lesion incidence. The failure load (ultimate compression tolerance (UCT)), loading stiffness, and failure morphology were assessed after acute compression loading and failure. The cartilaginous endplate is vulnerable to injuries such as Schmorl's nodes and fracture lesions. While both injuries are associated with acute compression traumas, the factors that distinguish their incidence are poorly understood. Forty-eight porcine spinal units (domestic hog, 5 - 10 months, ~110kg) were assigned to one of eight experimental groups that differed by initial condition (control, sham, experimentally produced chemical fragility, structural void) and loading rate (3 kN/s, 9kN/s). A servo-hydraulic materials testing system was used to perform acute compression testing until observed failure in the specimen. Post-loading dissection was performed to classify injury morphologies. Between group differences in UCT and loading stiffness were evaluated using a general linear model and injury distributions were evaluated using chi-squared statistics. Schmorl's nodes occurred exclusively in chemical fragility (63%) and structural void groups (37%) and were more prevalent with a 9 kN/s (75%) loading rate, compared to 3 kN/s (25%). In contrast, fracture lesions occurred in all FSUs assigned to the control groups (100%) and the majority of those assigned to the sham groups (92%). No between-group differences were observed for UCT and loading stiffness. Pre-existing strength deficits of the subchondral trabecular bone can alter endplate injury morphology, particularly when coupled with high loading rates, but the localized strength deficits that were associated with Schmorl's nodes did not appreciably influence measured joint properties.

Enhancing Power Quality in ON-Grid Systems with PV-STATCOM for Reactive Power Compensation

This research investigates the integration of an Artificial Neural Network (ANN) controlled boost inverter into a solar photovoltaic (PV) system connected to the utility grid. The boost inverter, equipped with a Static Synchronous Compensator (STATCOM), ensures stable grid voltage and enhances power quality. The ANN controller fine-tunes the DC-AC conversion process of the boost inverter in real-time, ensuring efficient operation under varying PV output and grid conditions. The system's performance was evaluated through simulations, demonstrating its ability to efficiently manage PV power generation and correct reactive power in local loads, thereby enhancing system reliability and grid stability.

A Multifidelity Framework for Aerothermodynamic Modeling and Simulation of Destructive Atmospheric Entry

The aerothermodynamic environment surrounding bodies undergoing destructive atmospheric entry is characterized by multiple interacting shock waves generated by the presence of several fragments moving close to one another at high speed. Shock interaction and impingement produce highly localized surface loads, influencing the overall dynamics of the fragment, its temperature, and in turn its demise. To account for the relevant physics during the reentry process of fragmenting bodies, a multifidelity framework is presented that allows for selecting the most appropriate level of fidelity, between high-fidelity solutions or low-fidelity aerothermodynamic metamodels. A physics-informed approach is implemented to automatically choose between the two fidelity levels on the basis of the intersection of shock wave envelopes. The complete framework is validated on relevant test cases from the literature and its performance is demonstrated for destructive atmospheric reentry cases, such as the case of the Attitude Vernier Upper Module and the Automated Transfer Vehicle from the European Space Agency.

A non-uniform lattice design method for lightweight structures in 3D printing

Lightweight design is an essential topic in aerospace, automotive and other fields. In automobile manufacturing, the engine connecting rod is one of the main components; its lightweight design has a high reference value. And 3D printing provides a feasible solution for designing and manufacturing lightweight structures. Unlike the traditional geometrically homogeneous point design, this study offers a non-homogeneous point design method based on the spatial stress state of additively manufactured components. After numerical simulation of quasi-static stresses on a model of an engine connecting rod, finite element grid cells with different stress values are replaced by lattice cells with different specific stiffnesses at similar local stress levels. The overall specific stiffness of the structure is further improved by continuing the optimized design with the corresponding gradient-type reinforcement of the non-uniform lattice structure. The basic idea of this design is to perform non-uniform adaptive filling of solid parts under localized loading by employing different types of unit cells. Stereolithography 3D printing technology prepares the engine lattice structural parts for quasi-static compression comparison experiments and fracture analysis after failure. The conclusions show that the engine connecting rod members with non-homogeneous lattice have more excellent overall mechanical properties than homogeneous lattice members. This work demonstrates the feasibility of such design methods for 3D printing lightweight structures and optimization.

Local considerations and experimental results on the contact behavior of crossed helical gears with general flank geometries

Crossed helical gears belong to gear units with crossed wheel axles and in most applications consist of a steel worm and a plastic wheel. Due to the high transmission ratio in a small installation space, they are used in actuators, auxiliary drives and positioning drives. The research into high-performance polymers is accompanied by increasingly powerful gears, de pending on the properties of the plastic material, to reach the load limits of steel materials. Research on steel/plastic crossed helical gears with geometrically optimized tooth flank geometries offers efficiency improvements and demonstrable efficiency potential, enabling higher overall load capacities and an increase in service life. A more detailed resolution of the contact behavior in the contact area allows friction energies to be considered and provides the basis for local wear and load capacity evaluations. Based on this, new crossed helical gears with general flank geometries can be designed, which have a positive influence on resource conservation and sustainability as a result of the increase in lifetime.

Reconstruction of the thermal evolution since the late paleozoic in the Ounan Sag, Eastern Qaidam Basin, NW China: New constraints from vitrinite reflectance data and (U–Th)/He thermochronology

Reconstructing the thermal evolution of the eastern Qaidam Basin is important for gaining a deeper understanding of its lithospheric geodynamics and for more accurate hydrocarbon evaluation and prediction. This article presents a set of new apatite and zircon (U–Th)/He thermochronological ages. Combined with 336 vitrinite reflectance (Ro) data, the thermal history of the Ouanan Sag in the eastern Qaidam Basin has been reconstructed using inversion models. Three detrital samples from the Ounan Sag shows that the apatite (U–Th)/He ages are primarily concentrated in the range of 17.0 Ma to 76.5 Ma and that the zircon (U–Th)/He ages range from 200 Ma to 289.3 Ma. The time-temperature models demonstrate that the Ounan Sag experienced rapid subsidence and heating from the Carboniferous to late Permian, and exhumation/cooling events from the end of Permian to the Triassic. This thermal evolution was influenced by the widespread intrusion of plutons, and the collision and orogenesis caused by asthenosphere upwelling below the Qaidam arc, and slab rollback of the Southern Kunlun oceanic lithosphere, respectively. Additionally, our models depict the main exhumation/cooling stages since the Paleogene and a reheating event in the Miocene as a result of the intensifying growth of the Qinghai–Tibet Plateau and local sedimentary loading, followed by the initial India–Eurasia collision. Furthermore, the eastern Qaidam Basin experienced consistent heating during the late Paleozoic, reaching the maximum paleotemperature and geothermal gradient in the late Permian, with values of ∼230 °C and ∼43–44 °C/km, respectively. This study suggests that the source rocks in the most upper member of upper Carboniferous Keluke (C2k) Formations in the Ounan Sag reached the gas generation stage in the late Permian.