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Search Results (10,347)

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19 pages, 16670 KiB  
Article
Study on Fire Temperature Field in Small-Section Steel-Shell Concrete Immersed Tube Tunnel Structure Based on CFD-FEM Method
by Bei Zhao, Baochao Xie, Zhisheng Xu, Feifan Wang and Yifan Gao
Materials 2025, 18(1), 187; https://doi.org/10.3390/ma18010187 (registering DOI) - 4 Jan 2025
Abstract
Small-section steel-shell concrete immersed tube tunnels are intended for minibuses and have a low fire heat release rate. Standard fire rise curves do not apply to such tunnels. In this study, a coupled method of computational fluid dynamics (CFD) and the finite element [...] Read more.
Small-section steel-shell concrete immersed tube tunnels are intended for minibuses and have a low fire heat release rate. Standard fire rise curves do not apply to such tunnels. In this study, a coupled method of computational fluid dynamics (CFD) and the finite element method (FEM) was used to simulate the structural temperature distribution in tunnels. Firstly, a tunnel fire dynamics model was established to obtain the inhomogeneous temperature field during tunnel fires. Subsequently, a three-dimensional heat transfer analysis model for the tunnel tube section was established to simulate the temperature transfer characteristics of the tunnel structure with and without fire protection measures under different types of vehicle fires. This study showed that because steel has a higher thermal conductivity, at the same depth, the temperatures were the highest in T-ribs, followed by partitions, and the lowest in concrete; however, the steel components inside the tunnel minimally affected the tunnel temperature. Without fire protection, the steel shell’s surface temperature exceeded 300 °C in as little as 500 s. Temperature’s primary impact on the tunnel’s steel structure was within 30 cm of the steel shell’s surface, and on concrete, it was within 20 cm. The greatest temperature difference between the partition and concrete occurred 10 cm from the steel shell’s surface. These results fill the knowledge gap on heat transfer in these tunnels and have positive practical significance for the fire resistance design of tunnels. Full article
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23 pages, 9965 KiB  
Article
Multi-Level Matching Optimization Design of Thin-Walled Beam Cross-Section for Tri-Axle Unmanned Forestry Vehicle Frame
by Qiang Chen, Yilu Zhao, Dequan Wang, Zhongjia Chen, Qingchun Wang and Xiangyue Yuan
Forests 2025, 16(1), 69; https://doi.org/10.3390/f16010069 - 3 Jan 2025
Viewed by 340
Abstract
With the advancement of forestry modernization, the research and development of forestry vehicles provide solid technical support for the efficiency and sustainability of forest operations. This study aims to reduce the mass of the forest-use tri-axle unmanned vehicle frame through structural optimization design, [...] Read more.
With the advancement of forestry modernization, the research and development of forestry vehicles provide solid technical support for the efficiency and sustainability of forest operations. This study aims to reduce the mass of the forest-use tri-axle unmanned vehicle frame through structural optimization design, improve its static and dynamic characteristics, and enhance vehicle mobility and environmental adaptability while maintaining or enhancing its structural strength and stability. Initially, the finite element model of the vehicle frame was established using the finite element software Hypermesh (2022), and its static and dynamic characteristics were analyzed using OptiStruct (2022) software. The accuracy of the finite element calculations was verified through experiments. Subsequently, a sensitivity analysis method was employed to screen the design variables of the thin-walled beam structure of the forest-use tri-axle unmanned vehicle. Response surface models were created using least squares regression (LSR) and radial basis function network (RBF). Considering indicators such as frame mass, modal frequency, and maximum bending and torsional stresses, the multi-objective genetic algorithm (MOGA) was applied to achieve a multi-objective lightweight design of the vehicle frame. This comprehensive optimization method is rarely reported in forestry vehicle design. By employing the proposed optimization approach, a weight reduction of 10.1 kg (a 7.44% reduction) was achieved for the vehicle frame without compromising its original static and dynamic performance. This significant lightweighting result demonstrates considerable practical application potential in the field of forestry vehicle lightweight design. It responds to the demand for efficient and environmentally friendly forestry machinery under forestry modernization and holds important implications for reducing energy consumption and operational costs. Full article
(This article belongs to the Section Forest Operations and Engineering)
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17 pages, 4103 KiB  
Article
Apelinergic System Affects Electrocardiographic Abnormalities Induced by Doxorubicin
by Kasper Buczma, Hubert Borzuta, Katarzyna Kamińska, Dorota Sztechman, Katarzyna Matusik, Jan Pawlonka, Michał Kowara, Barbara Buchalska and Agnieszka Cudnoch-Jędrzejewska
Biomedicines 2025, 13(1), 94; https://doi.org/10.3390/biomedicines13010094 - 3 Jan 2025
Viewed by 244
Abstract
Background/Objectives: Anthracyclines remain a pivotal element of numerous tumor management regimens; however, their utilization is associated with a range of adverse effects, the most significant of which is cardiotoxicity. Research is constantly being conducted to identify substances that could be incorporated into [...] Read more.
Background/Objectives: Anthracyclines remain a pivotal element of numerous tumor management regimens; however, their utilization is associated with a range of adverse effects, the most significant of which is cardiotoxicity. Research is constantly being conducted to identify substances that could be incorporated into ongoing cancer chemotherapy to mitigate anthracycline-induced cardiotoxicity. Recently, the apelinergic system has received a lot of attention in this field due to its involvement in cardiovascular regulation. Therefore, the aim of our study was to investigate the ability of the apelinergic system to inhibit the cardiotoxic effects of anthracycline—doxorubicin (DOX). Methods: In this study, 54 Sprague–Dawley rats were divided into seven groups and received intraperitoneal injections with DOX once a week for 4 consecutive weeks. The osmotic pumps provided a continuous release of NaCl (control groups), apelin-13 and elabela at two different doses, and the apelin receptor (APJ) antagonist ML221. Electrocardiography (ECG) and transthoracic echocardiography (TTE) with assessment of left ventricular (LV) systolic parameters were conducted on the first and last days of the experiment. Results: Lower doses of APJ agonists prevented the prolongation of QT and QTc intervals induced by DOX, while higher doses of these drugs exerted no such effect. The TTE examination confirmed DOX-induced LV systolic dysfunction. Moreover, the TTE examination revealed an improvement in the LV systolic parameters in the DOX-treated groups that were simultaneously administered APJ agonists. Conclusions: Our findings support the use of apelin and elabela as potential cardioprotective agents against anthracycline-induced cardiotoxicity. Full article
(This article belongs to the Section Molecular and Translational Medicine)
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16 pages, 2950 KiB  
Article
An Optimization Study on Continuous Steel Box Girder Bridge Components
by Ang Wang, Ruiyuan Gao, Qingfeng Chen, Weizhun Jin, Pengfei Fang and Di Wu
Buildings 2025, 15(1), 124; https://doi.org/10.3390/buildings15010124 - 3 Jan 2025
Viewed by 248
Abstract
The steel box girder bridge is a structure composed of mutually vertical stiffening ribs (longitudinal ribs and transverse ribs) that carry the loads of vehicles. Since the external loads are usually complex and variable, the rational design of the bridge components is a [...] Read more.
The steel box girder bridge is a structure composed of mutually vertical stiffening ribs (longitudinal ribs and transverse ribs) that carry the loads of vehicles. Since the external loads are usually complex and variable, the rational design of the bridge components is a topic that deserves more attention. The purpose of this study is to explore the optimal range of some of the component design parameters, expecting to reduce costs while ensuring the stress-carrying capacity. A finite element model (FEM) based on ABAQUS was built and the results were verified by laboratory experiments. The varied thicknesses of the bridge deck, diaphragm, and U-rib were explored based on the validated FEM. The simulation results fit well with the experimental results, which proved that the FEM was quite reliable. The stress analysis results demonstrated an optimal range of 18–20 mm for bridge deck thickness, 14–16 mm for diaphragm thickness, and 8–10 mm for U-rib thickness. The present study holds significant reference value for the design and optimization of multiple steel box girder bridge components, which could further provide a theoretical foundation for related research in this field. Full article
(This article belongs to the Section Building Structures)
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25 pages, 4894 KiB  
Article
Unsteady Loading on a Tidal Turbine Due to the Turbulent Wake of an Upstream Turbine Interacting with a Seabed Ridge
by Sulaiman Hurubi, Hannah Mullings, Pablo Ouro, Peter Stansby and Tim Stallard
Energies 2025, 18(1), 151; https://doi.org/10.3390/en18010151 - 2 Jan 2025
Viewed by 259
Abstract
Tidal sites can present uneven seabed bathymetry features that induce favourable or adverse pressure gradients and are sources of turbulence, and so are likely to affect the operation, performance, and wake recovery dynamics of deployed tidal-stream turbines. Large-eddy simulations are conducted to analyse [...] Read more.
Tidal sites can present uneven seabed bathymetry features that induce favourable or adverse pressure gradients and are sources of turbulence, and so are likely to affect the operation, performance, and wake recovery dynamics of deployed tidal-stream turbines. Large-eddy simulations are conducted to analyse the unsteady loading of a tidal turbine subjected to the wake of an upstream turbine that interacts with a two-dimensional ridge located between the two turbines. Relative to an isolated turbine, blade fatigue loading is increased by up to 43% when subject to the wake of a turbine located 8 turbine diameters upstream interacting with a ridge located 2 turbine diameters upstream, whereas for the same spacing, the turbine wake led to a limited 6% reduction in loading and the ridge wake only caused a 79% increase. For larger spacings, the trends were similar, but the magnitude of difference reduced. Predictions of fatigue loads with a blade element momentum model (BEMT) provided a good agreement for flat bed conditions. However, the ridge-induced pressure gradient drives rapid spatial change of coherent flow structures, which limits the applicability of Taylor’s frozen turbulence hypothesis adopted in the BEMT. Reasonable prediction of rotor loading with BEMT was found to be obtained using the turbulent onset flow field at a plane one-diameter upstream of the turbine. This is more accurate than use of the planes at the rotor plane or two-diameters upstream, as coherent structures represent those modified by wake recovery and rotor induction in the approach flow to the turbine. Full article
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17 pages, 4426 KiB  
Article
Optimal Multi-Physics Synthesis of a Dual-Frequency Power Inductor Using Deep Neural Networks and Gaussian Process Regression
by Paolo Di Barba, Arash Ghafoorinejad, Maria Evelina Mognaschi, Fabrizio Dughiero, Michele Forzan and Elisabetta Sieni
Algorithms 2025, 18(1), 10; https://doi.org/10.3390/a18010010 - 2 Jan 2025
Viewed by 182
Abstract
In this paper, a multi-physics case study belonging to the class of induction heating problem is considered. Finite Element Analysis is used to evaluate the temperature along a line on a graphite disk heated by two power inductors. In order to build a [...] Read more.
In this paper, a multi-physics case study belonging to the class of induction heating problem is considered. Finite Element Analysis is used to evaluate the temperature along a line on a graphite disk heated by two power inductors. In order to build a surrogate field model of the device, i.e., to compute the temperature profile on the disk, given the amplitudes and frequencies of the supply currents, three methods have been used (Support Vector Regression (SVR), fully connected Neural Network (NN) and Gaussian Process Regression (GPR)). In turn, to solve the inverse problem, i.e., to identify frequencies and currents of the two coils, given a prescribed temperature profile, two approaches have been implemented. The former is an optimization approach based on a multi-objective formulation, solved by means of the NSGA-II algorithm; the latter is a two-step procedure, based on fully connected Deep Neural Networks (DNNs), solving an optimal design problem first and, subsequently, an optimal control problem. Full article
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35 pages, 4557 KiB  
Review
A Review of Segmented Stator and Rotor Designs in AC Electric Machines: Opportunities and Challenges
by Bhuvan Khoshoo, Anmol Aggarwal and Shanelle Foster
Eng 2025, 6(1), 7; https://doi.org/10.3390/eng6010007 - 1 Jan 2025
Viewed by 415
Abstract
The use of segmented stator and rotor designs in AC electric machine construction offers several significant advantages, including a high-copper fill factor, increased torque density, improved field-weakening performance, simplified manufacturing processes, and enhanced mechanical strength. Additionally, segmented designs allow for the incorporation of [...] Read more.
The use of segmented stator and rotor designs in AC electric machine construction offers several significant advantages, including a high-copper fill factor, increased torque density, improved field-weakening performance, simplified manufacturing processes, and enhanced mechanical strength. Additionally, segmented designs allow for the incorporation of oriented steel—either partially or fully—which exhibits excellent magnetic properties in the rolling direction, resulting in more efficient machine performance. However, lamination segmentation also introduces challenges. Parasitic air gaps between segments and an increased number of cut edges in the assembled stack can alter the magnetic properties of the machine, potentially leading to degraded performance. Furthermore, the use of oriented steel remains complex, as its highly nonlinear magnetic properties vary depending on the direction of the magnetic flux. This paper reviews the widely adopted stator and rotor segmentation techniques available in the literature, discussing their potential benefits and limitations. It also covers key aspects such as popular manufacturing approaches, the impact of segmentation on machine performance, advanced finite-element analysis (FEA) techniques for numerical modeling, and experimental methods for evaluating the performance of segmented stator and rotor constructions in AC machines. By addressing these areas, this work provides a comprehensive resource for machine designers seeking to develop AC machines with segmented stators and rotors. Full article
(This article belongs to the Special Issue Women in Engineering)
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17 pages, 3464 KiB  
Article
Design and Implementation of a Binary Phase-Shift Keying Frequency Diverse Array: Considerations and Challenges
by Nicholas R. Munson, Bill Correll, Justin K. A. Henry, Ram M. Narayanan and Travis D. Bufler
Sensors 2025, 25(1), 193; https://doi.org/10.3390/s25010193 - 1 Jan 2025
Viewed by 321
Abstract
The frequency diverse array (FDA) is an architecture capable of beamforming in both range and angle, improving upon the traditional phased array (PA) which can only achieve beamforming in angle. The FDA employing directional modulation (DM) for secure directional communications (SDC) can reduce [...] Read more.
The frequency diverse array (FDA) is an architecture capable of beamforming in both range and angle, improving upon the traditional phased array (PA) which can only achieve beamforming in angle. The FDA employing directional modulation (DM) for secure directional communications (SDC) can reduce bit error rates (BERs) in both range and angle, again improving upon the traditional PA which can only reduce BER in angle. In this paper, we document the challenges involved in the design and implementation of a two-element linear FDA employing fast-time binary phase-shift keying (BPSK) modulations. We also show that the experimentally collected field data match well with the results of simulations based on our analytical model. Full article
(This article belongs to the Section Remote Sensors)
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13 pages, 3519 KiB  
Article
Design of Prestressed Cable Dome Using Minor Perturbation Method
by Haitao Zhou, Feng Fu, Bo Si, Deqing You and Fengjian Zhang
Buildings 2025, 15(1), 114; https://doi.org/10.3390/buildings15010114 - 31 Dec 2024
Viewed by 299
Abstract
For the structural design of cable domes, the determination of prestress force distribution, the section of the structural components, and initial configuration are prerequisites for the subsequent detailed design of cable and strut sizes. To solve this problem, this paper elucidates the basic [...] Read more.
For the structural design of cable domes, the determination of prestress force distribution, the section of the structural components, and initial configuration are prerequisites for the subsequent detailed design of cable and strut sizes. To solve this problem, this paper elucidates the basic theory of the Minor Perturbation Method, introduces this theory into the field of force finding design for cable dome structures, and develops a new design method whose core is the comparison between the combined stress of each component conforming to mechanical characteristics of cable-strut structure and control stress, and meeting the convergence condition by adjusting the prestress level and cross-section of components. A corresponding design flow chart is established and programmed with finite element analysis software. Through the case studies of two different kinds of cable dome, it is proven that the proposed method and software program can simply, quickly, and effectively design the cable domes with an economic cross-section. Full article
(This article belongs to the Special Issue Building Structure Mechanical Properties and Behavior Analysis)
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25 pages, 6319 KiB  
Article
Research on the Effect of Nonlinear Variation in Insulation Resistance on the Voltage Divider Ratio of 2 × 550 kV DC Voltage Proportional Standard Device
by Yin Gao, Ximing Chen, Yuqing Duan, Ran Gao, Chao Wang, Zheng Chen, Fei Lin, Lei Zhuang, Wanjun Zhu, Min He and Liang Qin
Electronics 2025, 14(1), 138; https://doi.org/10.3390/electronics14010138 - 31 Dec 2024
Viewed by 340
Abstract
This paper investigates the effect of nonlinear changes in insulation resistance on the accuracy of a 2 × 550 kV DC voltage scaling standard device. As the voltage and electric field strength increase, the insulating material exhibits nonlinear conductivity characteristics, leading to a [...] Read more.
This paper investigates the effect of nonlinear changes in insulation resistance on the accuracy of a 2 × 550 kV DC voltage scaling standard device. As the voltage and electric field strength increase, the insulating material exhibits nonlinear conductivity characteristics, leading to a decrease in the insulation resistance value, which in turn affects the potential distribution and the partial voltage ratio and thus reduces the measurement accuracy of the standard device. In order to study this problem in depth, this paper builds a nonlinear resistance measurement platform for insulating materials, and it fits and analyzes the experimental data using an NCIR neural network (Neural Network for Nonlinear Characteristics of Insulation Resistance). In addition, in this paper, the finite element model of the standard device was established by ANSYS simulation, and the equivalent resistance network model was established by applying MATLAB in order to calculate the variation in the voltage dividing ratio under different voltages. The results of the study showed that the nonlinear variation in insulation resistance significantly affects the voltage division ratio of the standard device, especially at high voltage conditions. Addressing the issue, this paper proposes to optimize the electric field distribution by optimizing the structure of the grading ring and adding a shielding resistor layer to reduce the influence of nonlinear effects. Simulation results show that the addition of a second layer to the shielding resistor can effectively improve the measurement accuracy of the device, and the reduction in voltage division ratio error is significant. Compared with the case of a shielding resistor with only one layer, the voltage divider ratio was reduced from 109,998.203 to 109,998.994, and the relative error was reduced 44%, changing from 1.634 × 10−5 to 9.15 × 10−6. The above study provides an optimized solution for achieving high-precision DC voltage measurement. Full article
(This article belongs to the Special Issue High-Voltage Technology and Its Applications)
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14 pages, 2963 KiB  
Article
Synthesis, Structure, and Electrophysical and Electrochemical Properties of Novel Composite La0.9MnO3-LaFeO3
by Mukhametkali Mataev, Zamira Sarsenbaeva, Bahadir Keskin, Marzhan Nurbekova, Amangeldi Meldeshov, Zhanar Tursyn and Karima Seitbekova
Molecules 2025, 30(1), 132; https://doi.org/10.3390/molecules30010132 - 31 Dec 2024
Viewed by 443
Abstract
This article presents the synthesis, electrophysical, and catalytic properties of a La0.9MnO3–LaFeO3 nanocomposite material. The nanocomposite was synthesized via the sol–gel (Pechini) method. X-ray diffraction (XRD) analysis revealed a polycrystalline, biphasic perovskite structure combining both hexagonal and cubic [...] Read more.
This article presents the synthesis, electrophysical, and catalytic properties of a La0.9MnO3–LaFeO3 nanocomposite material. The nanocomposite was synthesized via the sol–gel (Pechini) method. X-ray diffraction (XRD) analysis revealed a polycrystalline, biphasic perovskite structure combining both hexagonal and cubic symmetry. The microstructure and elemental composition, examined using field emission scanning electron microscopy (FESEM), indicated an average particle size of approximately 186.9 nm. The composite exhibits semiconducting behavior within the temperature ranges of 293–323 K and 343–393 K. Developing electrocatalysts free of precious metals for the hydrogen evolution reaction (HER) is increasingly important to facilitate the production of hydrogen from renewable sources. In this study, the conductive La0.9MnO3–LaFeO3 composite was deposited on graphite and, for the first time, evaluated as an electrocatalyst for HER in acidic media. The resulting composite films were tested using linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) in a glassy carbon electrode (GCE) setup, providing insights into their potential as effective, cost-efficient electrocatalysts. Full article
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16 pages, 3330 KiB  
Review
Quantitative 31P NMR Spectroscopy: Principles, Methodologies, and Applications in Phosphorus-Containing Compound Analysis
by Yaqin Liu, Lina Gao and Zeling Yu
Appl. Sci. 2025, 15(1), 323; https://doi.org/10.3390/app15010323 - 31 Dec 2024
Viewed by 371
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is gaining prominence as a vital quantitative method for sample analysis, with significant progress being made in the investigation of heteronuclei like phosphorus, a key element in numerous physiological functions. This paper provides a comprehensive review of the [...] Read more.
Nuclear magnetic resonance (NMR) spectroscopy is gaining prominence as a vital quantitative method for sample analysis, with significant progress being made in the investigation of heteronuclei like phosphorus, a key element in numerous physiological functions. This paper provides a comprehensive review of the principles, methodologies, and applications of quantitative 31P nuclear magnetic resonance (qNMR) spectroscopy. It begins with an introduction to the fundamental principles of NMR spectroscopy, highlighting the specific advantages of qNMR and the unique properties of the 31P nucleus, including its high natural abundance and broad chemical shift range. While 1H qNMR is widely used, signal overlap in complex mixtures can limit its accuracy. Additionally, this work explores diverse applications of 31P qNMR across fields such as food analysis, pharmaceuticals, and biology, emphasizing its contributions to real-time drug quantification, metabolomics, and environmental analysis. A key advantage of 31P NMR is its ability to provide exclusive detection and direct quantification of phosphorus in phosphorus-containing compounds. The internal standard method is favored for its simplicity, as it avoids the need for calibration curves, while the external standard method is better suited for natural products with established reference materials. This review aims to consolidate the applied prospects of 31P qNMR, emphasizing its potential to expand the horizons of quantitative detection technologies and facilitate advancements in future research and practical applications. Full article
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29 pages, 5710 KiB  
Article
Study on Discrete Null-Field Equation Methods for Bounded Simply Connected Domains: Better Locations of Source Nodes
by Li-Ping Zhang, Zi-Cai Li, Hung-Tsai Huang, Ming-Gong Lee and Alexander L. Kazakov
Mathematics 2025, 13(1), 131; https://doi.org/10.3390/math13010131 - 31 Dec 2024
Viewed by 312
Abstract
The discrete null-field equation method (DNFEM) was proposed based on the null-field equation (NFE) of Green’s representation formulation, where only disk domains were discussed. However, the study of the DNFEM for bounded simply connected domains S is essential for practical applications. Since the [...] Read more.
The discrete null-field equation method (DNFEM) was proposed based on the null-field equation (NFE) of Green’s representation formulation, where only disk domains were discussed. However, the study of the DNFEM for bounded simply connected domains S is essential for practical applications. Since the source nodes must be located outside of a solution domain S, the first issue in computations is how to locate them. It includes two topics—Topic I: The source nodes must be located not only outside S but also outside the exterior boundary layers. The width of the exterior boundary layers is derived as O(1/N), where N is the number of unknowns in the DNFEM. Topic II: There are numerous locations for source nodes outside the exterior boundary layers. Based on the sensitivity index, several better choices of pseudo-boundaries are studied for bounded simply connected domains. The advanced study of Topics I and II needs stability and error analysis. The bounds of condition numbers (Cond) are derived for bounded simply connected domains, and they are similar to those of the method of fundamental solutions (MFS). New error bounds are also provided for bounded simply connected domains. The thorough study of determining better locations of source nodes is also valid for the MFS and the discrete boundary integral equation method (DBIEM). The development of algorithms based on the NFE lags far behind that of the traditional boundary element method (BEM). Some progress has been made by following the MFS, and reported in this paper. From the theory and computations in this paper, the DNFEM may become a competent boundary method in scientific/engineering computing. Full article
21 pages, 11713 KiB  
Article
Superplastic Forming/Diffusion Bonding of TA15 Titanium Alloy for Manufacturing Integrated Solid/Hollow Four-Layer Grid Lightweight Structure Components
by Zheng Han, Yuhan Xing, Taiying Liu, Ning Zhang, Shaosong Jiang and Zhen Lu
Metals 2025, 15(1), 28; https://doi.org/10.3390/met15010028 - 31 Dec 2024
Viewed by 299
Abstract
In recent years, the excellent mechanical properties and lightweight characteristics of multi-layer hollow components have led to a surge in research focused on their forming processes. This growing interest has greatly advanced technological progress in aerospace and other related fields. In this paper, [...] Read more.
In recent years, the excellent mechanical properties and lightweight characteristics of multi-layer hollow components have led to a surge in research focused on their forming processes. This growing interest has greatly advanced technological progress in aerospace and other related fields. In this paper, the metal flow behavior of TA15 titanium alloy at different temperatures from 840 °C to 940 °C and different strain rates from 0.001 s−1 to 0.1 s−1 was studied. Utilizing the finite element method, this study examined the local stress concentration, total strain distribution, thickness thinning characteristics, and pressure loading control during the superplastic forming process of the component. The integrated solid/hollow four-layer grid lightweight structural parts were successfully fabricated using the superplastic forming/diffusion bonding (SPF/DB) process. The quality of the components was evaluated using X-ray and ultrasonic C-scan detection methods. The results show that the maximum elongation of the alloy is 1340% at 900 °C/0.001 s−1. When the temperature is too high, the grain size increases remarkably, and the elongation decreases. Based on the finite element simulation results, 900 °C is the best superplastic forming temperature. Under this temperature parameter, the maximum thinning rate of the core sheet is 39.7%, the SPF time is 10,000 s, the maximum thinning rate of the face sheet is 9.8%, and the SPF time is 2400 s. In addition, the solid block has a minimal effect on the thinning of the core sheet. The grid exhibits obvious stress concentration and thinning at its rounded corners, while the thickness distribution in other areas remains relatively uniform. The nondestructive testing results confirmed that the ribs of the component are fully formed, with no missing or broken ribs. The grid exhibits good geometry and high-quality diffusion bonding. The average thickness at key positions of the component is 1.84 mm, with the minimum thickness being 1.7 mm. As the size of the grid cavity decreases, the thickness of the component tends to increase gradually. The maximum error between the simulated and measured values is 4.47%, indicating good accuracy in the simulation. Additionally, the thickness distribution of the component is relatively uniform. Full article
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23 pages, 9911 KiB  
Article
Evolution and Future Challenges of Hydrological Elements in the Qinglongshan Irrigation Area: A Study on the Impact of Climate Change and Land Use Based on the Soil and Water Assessment Tool for the Qinglongshan Irrigation Area Model
by Ziwen Yin, Yan Liu, Zhenjiang Si, Longfei Wang, Tienan Li and Yan Meng
Sustainability 2025, 17(1), 239; https://doi.org/10.3390/su17010239 - 31 Dec 2024
Viewed by 370
Abstract
In this study, the Soil and Water Assessment Tool (SWAT) model was first initialized for the Qinglongshan Irrigation Area (QLS). We aimed to assess the impacts of climate and land use (LULC) changes between 1980 and 2020 on several hydrological parameters in the [...] Read more.
In this study, the Soil and Water Assessment Tool (SWAT) model was first initialized for the Qinglongshan Irrigation Area (QLS). We aimed to assess the impacts of climate and land use (LULC) changes between 1980 and 2020 on several hydrological parameters in the QLS, including actual evapotranspiration (ET), soil water (SW), soil recharge to groundwater (PERC), surface runoff (SURQ), groundwater runoff (GWQ), and lateral runoff (LATQ). We predicted the trends in hydrological factors from 2021 to 2050. Based on the S1 scenario, the precipitation and the paddy field area decreased by 42.28 mm and 1717.65 km2, respectively; hydrological factors increased by 91.53, 104.28, 50.66, 21.86, 55.93, and 0.79 mm, respectively, in the QLS. Climate changes contributed 6.10%, −7.58%, −54.11%, 26.90%, −121.17%, and −31.66% to changes in hydrological factors, respectively; LULC changes contributed −2.19%, 3.63%, 11.61%, −2.93%, 25.89%, and 16.86%, respectively; and irrigation water volume changes contributed 96.09%, 103.95%, 142.50%, 76.03%, 195.28%, and 114.80%, respectively. Irrigation and water intake were the main factors affecting the changes in hydrological elements. This was followed by climatic changes and LULC. In natural development scenarios, the QLS is anticipated to face challenges, including increased actual ET, reduced seepage and groundwater contribution, and declining groundwater levels. Full article
(This article belongs to the Section Air, Climate Change and Sustainability)
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