International Core Journal of Engineering
International Core Journal of Engineering is an international journal to promote all fields of Engineering, it considers original and timely contributions containing new results in mechanical engineering, electrical engineering, civil engineering, chemical engineering, etc. All articles published are rigorously and fast reviewed meeting the Journal Quality standards.
Category Home Online Custom One-click Quotation System and Method
Aiming at the problems of low quotation efficiency, poor real-time price, isolated front-end and back-end data, high artificial dependence, and non-standard pricing in traditional online customization of home furnishings, this paper proposes an online customization one-click quotation system and implementation method based on product configuration theory, multi-dimensional linkage constraint model, real-time intelligent pricing model, and ERP order state machine model. The system consists of four modules : commodity price basic database, quotation front-end page, one-click quotation operation module and ERP order processing module. Through parameter standardization, configuration linkage, pricing formulation and order integration, the user-side one-click real-time quotation and enterprise-side order automatic transfer production are realized. The simulation results show that the average quotation time of the system is reduced from 145 s to less than 1.5 s, the quotation accuracy rate is more than 99.3 %, and the order review and production scheduling efficiency are improved by 82 %. It effectively solves the problem of online quotation and offline production coordination in door industry customization, significantly improves user experience and enterprise operation efficiency, and provides technical reference for mass customization in home building materials industry.
Category Home; Online Customization; One-click Quotation; Product Configuration Theory; ERP Integration.
Copyright (c) 2026 International Core Journal of Engineering https://creativecommons.org/licenses/by-nc/4.0
Mechanism Design and Simulation Analysis of an Underactuated Hexapod Robot
To reduce the control complexity and algorithm development difficulty of conventional hexapod robots (which require 18 servo motors), a leg mechanism for a hexapod robot based on the underactuated principle was designed using SolidWorks. This design omits the ankle joint servo, instead using a single servo combined with a tendon-driven transmission system to actuate both the knee joint and ankle joint in a coupled manner, while a torsion spring provides the restoring torque required for leg lifting. A kinematic model of the leg was established based on the D-H parameter method, and both forward and inverse kinematic analyses of the foot-end effector were performed. The desired foot-end trajectory was obtained through MATLAB simulation. Dynamic simulation analysis of the mechanical leg mechanism was carried out using ADAMS, which verified the correctness and feasibility of the above underactuated structural design and theoretical model, providing a theoretical basis for the development of a physical prototype of the underactuated hexapod robot.
Underactuated; Hexapod Robot; Kinematic Model; ADAMS Analysis.
Research Progress on the Permeability of Flexible Sealing Layer in Artificial Cavern for Compressed Air Energy Storage
Aiming at the permeability of flexible sealing layer in artificial cavern for compressed air energy storage, the engineering application cases of flexible materials as sealing layers are sorted out. The current research progress in experimental research, theoretical analysis and numerical simulation in this field is expounded, and the advantages and disadvantages of each research method are analyzed. On this basis, the future research direction in this field is prospected. It is believed that in the future, key variables such as air pressure, temperature, tension state and cycle times should be comprehensively considered in the penetration test to reveal the penetration law of flexible materials. At the same time, the penetration evolution model is constructed and numerical calculation is introduced to further explore the multi-field coupling response characteristics of flexible sealing layer.
Flexible Sealing Layer; Permeability; Experimental Study; Theoretical Analysis; Numerical Simulation.
Study on Hydraulic Performance of Modular Constructed Wetlands based on Baffle Optimization
This study addresses the severe clogging, challenging construction quality control, and high maintenance costs associated with traditional constructed wetlands by exploring structural optimization approaches for modular constructed wetlands (MCW). To gain an intuitive understanding of the internal flow patterns within modular constructed wetlands, a three-dimensional CFD simplified porous medium model was developed using FLUENT software. To further optimize the hydraulic efficiency of the modular wetland system, the impact of baffle arrangement on overall hydraulic performance was systematically investigated. Nine baffle configuration modes were compared in simulations, revealing that a configuration with two inner baffles represented the optimal solution: it achieved a flow field uniformity index of 0.68, an effective volume ratio of 0.815, a hydraulic efficiency of 0.792, and a fluid dispersion coefficient of merely 0.028. Increasing the number of baffles or concentrating them inward significantly degraded the flow field, resulting in a hydraulic efficiency of only 0.441 for a configuration with four inner baffles. This study validates the effectiveness of CFD-based structural parameter optimization, providing a quantitative theoretical foundation and practical technical solutions for efficient, standardized design of modular constructed wetlands.
Modular Constructed Wetlands; Numerical Simulation; Flow Field Distribution; Hydraulic Characteristics; Structural Optimization Design.
Fire Prevention Technology Practice in Syncline Structure Area based on Inhibitor Spraying and Tube Bundle Monitoring
To address the “water-gas-structure” multi-field coupling disaster encountered by the 9401 fully mechanized top-coal caving face at Hengsheng Coal Mine while passing through the Liujiazhuang syncline axis, the three-dimensional compound air leakage mechanism composed of “boreholes, overlying goaf, and surface fissures” and the associated risk of residual coal spontaneous combustion were analyzed in depth. Consequently, an active prevention and control system centered on mobile calcium chloride inhibitor spraying was constructed. A calculation model for the inhibitor dosage based on mining parameters was established, determining the optimal daily spray volume at 9.98 m³, accompanied by the implementation of a hierarchical dynamic control strategy. Combined with a beam tube monitoring system, full-process dynamic tracking of key gas components in the goaf, including O2, CH4, CO2, and CO, was conducted. Field application results indicated that during the implementation, the gas flow field in the goaf remained generally stable. The peak methane concentration was controlled below 0.55%, and carbon monoxide levels consistently remained at low background values without abnormal fluctuations. This system effectively blocked compound air leakage channels, inhibited the oxidation process of residual coal, and ensured safe mining operations under complex geological conditions.
Syncline Axis; Compound Air Leakage; Inhibitor Spraying; Beam Tube Monitoring; Prevention of Coal Spontaneous Combustion.
Study on the State Evolution and Long-Term Stability Control of Subgrades
As highway engineering in China shifts from large-scale construction to long-term maintenance, the influence of long-term subgrade stability on pavement service performance has become increasingly prominent. Current construction control practices mainly rely on stage-specific indicators such as the degree of compaction, which cannot fully capture the continuous evolution of subgrade conditions under traffic loading, moisture fluctuations, wetting–drying cycles, and freeze–thaw actions. From a life-cycle perspective, this paper analyzes the relationships among compaction state, moisture condition, and mechanical response, and discusses the effects of key parameters-including degree of compaction, porosity, water content, degree of saturation, matric suction, and resilient modulus-on subgrade performance. The study suggests that subgrade stability is jointly governed by fill material properties, compaction energy, moisture migration, particle rearrangement, and cumulative loading effects. Future evaluation should shift from single-index control based on compaction degree toward a coordinated assessment using multiple state parameters, thereby providing a basis for subgrade distress diagnosis, performance prediction, and maintenance decision-making.
Subgrade State; Long-term Stability; Degree of Compaction; Moisture Condition; Resilient Modulus.
Construction Technology and Application of Graphite-based Flexible Grounding Bodies for Wind Farms and Photovoltaic Power Stations
To fundamentally solve the challenges of grounding grid corrosion, difficult construction, and high environmental risk in highly corrosive and high-resistivity complex terrain areas for wind farms and photovoltaic (PV) stations, a complete set of construction techniques for graphite-based flexible grounding bodies is proposed and systematically summarized. This technology uses high-carbon flake graphite as the main body material, utilizes the principles of electric field dispersion and composite anti-corrosion, ensures long-term resistance reduction, and completely avoids open-flame operations in the field. This paper elaborates on the construction process flow, key operation points, materials and equipment, and quality control measures for graphite-based flexible grounding bodies. Through life-cycle cost analysis and typical engineering case verification, its technical and economic superiority is demonstrated. The results show that this method can stably maintain grounding resistance below the design value, reduce the life-cycle cost by approximately 60% compared with the traditional copper-clad steel scheme, and avoid heavy metal pollution, offering significant economic, social, and environmental benefits.
Graphite-based Flexible Grounding Body; Wind Farm; Photovoltaic Power Station; Grounding Grid Construction; Anti-corrosion and Resistance Reduction.
Dynamic Process Control based on an AI Model Cluster for Atmospheric and Vacuum Distillation
From November 2024 to August 2025, a data-driven real-time closed-loop optimization project was carried out for a 10 Mt/a atmospheric and vacuum distillation unit. The study was intended to address the strong coupling, frequent operating-mode switching, and limited long-term effectiveness of conventional optimization methods in large crude distillation systems. A process-oriented artificial intelligence (AI) model cluster was therefore developed by using full-process modular artificial neural networks (ANNs) to characterize the coupled states of the unit and reflect changes in operating conditions. On this basis, an intelligent execution system (iES) was built to translate plant-wide optimization results into dynamic control targets acceptable to the field, which were then implemented through multivariable advanced control schemes at the distributed control system (DCS) level. Industrial application shows that, within quality and safety boundaries, this method can transfer optimization solutions to the production unit in a safe and stable manner, demonstrating good industrial applicability.
Atmospheric and Vacuum Distillation; Process AI Model Cluster; Dynamic Optimization; Intelligent Control System; Expert Knowledge.
Research on the Application of Life Cycle Method in Carbon Emission Accounting of Rural Households
Against the dual background of China's "dual carbon" goal and the rural revitalization strategy, the low - carbon development of rural areas is a key link in achieving carbon emission reduction across society. This paper integrates the carbon emission accounting method of the Intergovernmental Panel on Climate Change and the life cycle assessment method to construct a nested carbon emission accounting framework of "four stages and three modules" suitable for rural households. Taking rural households in Tangshan City, Hebei Province as the research object, the study found that: the operation and use stage of rural household carbon emissions contributes the vast majority of emissions, followed by the building material production stage. Electricity consumption, embodied carbon in building materials, and emissions from small - scale breeding constitute the three core emission sources. The accounting framework constructed in this paper provides methodological support for the accurate accounting of rural household carbon emissions, and the research conclusions can provide a reference for rural low - carbon development decision - making.
Life Cycle Assessment; Rural Households; Carbon Emission Accounting; Rural Areas in Hebei.
Preparation of Co-BDC/Ti3C2Tx Composite Materials for High-performance Supercapacitor Electrodes
Ti₃C₂Tₓ MXene holds great potential for supercapacitor electrodes, yet its performance is hindered by nanosheet restacking. Herein, a Co-BDC/Ti3C2Tx composite is fabricated by in situ growth of a cobalt-based MOF on MXene nanosheets. This unique architecture synergistically integrates the high conductivity of MXene with the large surface area and rich pseudocapacitance of MOF, leading to significantly enhanced electrochemical performance. The composite electrode exhibits a superior areal capacitance of 10.31 F cm-2 at 2 mA cm-2. A solid-state asymmetric supercapacitor constructed with this composite delivers an energy density of 0.741 mW cm-2 at a power density of 0.483 mWh cm-2 and retains 89% of its initial capacitance after 5000 cycles, highlighting its remarkable cycling stability. This work presents an effective strategy for designing high-performance MXene-based electrodes for next-generation flexible energy storage devices.
Supercapacitor; Electrochemistry; Composite Materials; Energy Storage.
Research on Terahertz Band-stop Filter based on Circular Quasi-periodic Waveguide
The terahertz filtering behavior of quasi-periodic waveguide based Fibonacci sequence is investigated by finite element research method. The long-range order of quasi-periodic waveguide has achieved the functions of band-stop and narrow band filter. The waveguide generation can directly influence the number of bandgaps. Periodic processing can enable low generation waveguides to have the band-stop filtering function, too. The length ratio can be used to regulate the number of forbidden bands, operating frequency and bandwidth. The maximum bandwidth of a single bandgap is 192 GHz. The total operating frequency of a single waveguide can reach up to 281 GHz. The 8th generation waveguide also realizes narrow band filtering function with a bandwidth of 14 GHz. Quasi-periodic waveguides can provide new ideas for the design of terahertz filters.
Terahertz; Band-stop Filter; Quasi-periodic; Waveguide.
Trajectory Tracking Control of Quadrotor UAV based on Parallel Cooperative PID-MPC Architecture
Quadrotor UAV trajectory tracking control, PIDMPC parallel cooperative architecture, feedforward-feedback fusion mechanism, event-triggered strategy, fuzzy adaptive parameter tuning, MATLAB/Simulink simulation validation. To address the problem that the advantages of Model Predictive Control (MPC) cannot directly assist the Proportional-IntegralDerivative (PID) controller in the traditional cascade PID-MPC control structure, this paper proposes a PID-MPC parallel cooperative control architecture. This architecture employs MPC as the feedforward channel for trajectory prediction and lookahead optimization, and PID as the feedback channel for rapid error correction, synthesizing the outputs of both into the final control input through a dynamic weighted fusion mechanism. To reduce the online computational burden of MPC, an eventtriggered mechanism based on the state error norm is introduced, which activates the MPC solver only when the error exceeds a threshold. Meanwhile, a fuzzy inference system is designed to achieve online adaptive tuning of PID parameters. On the MATLAB/Simulink platform, using a quadrotor UAV nonlinear dynamics model as the plant, the proposed method is compared with three baseline controllers-pure PID, pure MPC, and traditional cascade PID-MPC-under four scenarios: figure-8 complex trajectory tracking, pulse and continuous wind disturbance rejection, model parameter mismatch robustness, and computational efficiency. Experimental results demonstrate that the proposed parallel cooperative architecture achieves a root mean square tracking error (RMSE) of 0.047m, representing reductions of 78.1% compared to pure PID, 52.5% compared to pure MPC, and 41.3% compared to the traditional cascade structure; the recovery time under pulse wind disturbance is only 0.826s, and the steady-state error under continuous wind disturbance is 0.031m; the MPC trigger rate is reduced to 38.7%, with an average single-step solving time of 2.134ms, satisfying real-time requirements.
Quadrotor UAV; Model Predictive Control; PID Control; Parallel Cooperative Architecture; Event-triggered Mechanism; Fuzzy Adaptive; Trajectory Tracking.
Microstructure and High-temperature Friction Wear Properties of Laser-cladded Fe20Co20Cr20Ni25AlxTi(15-x) High-entropy Alloy Coatings
High-speed train brake discs at 400 km/h are coated with Fe20Co20Cr20Ni25AlxTi(15-x) high-entropy alloy to improve the service performance of the discs and ensure train safety. In this study, Fe20Co20Cr20Ni25AlxTi(15-x) high-entropy alloy coating was successfully prepared on 24CrNiMo, a steel-based material for brake discs, and its microstructure and hardness, high-temperature frictional wear properties, and mechanism were investigated. It was discovered that the phase structure of the Fe20Co20Cr20Ni25AlxTi(15-x) high-entropy alloy cladding layer is the face-centered cubic phase, and the microstructure of the clad layer is flat crystal, columnar crystal, dendritic crystal and equiaxed crystal from the bottom to the top in order. The average friction coefficient of Fe20Co20Cr20Ni25AlxTi(15-x) high-entropy alloy is between 0.3 and 0.6, which is lower than that of the substrate. The room temperature and high-temperature wear rates of Fe20Co20Cr20Ni25Al5Ti10 were reduced by 51.1% and 74.2%, respectively, compared to the substrate, with enhanced wear performance. The room-temperature wear mechanism of Fe20Co20Cr20Ni25AlxTi(15-x) was all abrasive wear, and the high-temperature wear mechanisms were oxidation wear, adhesive wear and abrasive wear.
High-speed Train Brake Disc; Laser Cladding; High-entropy Alloy; High-temperature Friction Wear.
Research on Obstacle Detection and Distance Measurement for the Blind based on Improved YOLOv7-Tiny
In the daily walking process of visually impaired individuals, the accuracy of obstacle detection and distance measurement is crucial to their safety. This paper proposes an improved obstacle detection and recognition algorithm based on YOLOv7-Tiny. The algorithm adds a three-dimensional attention mechanism module, SimAM, to the Neck-to-Head part of the lightweight YOLOv7-Tiny network to enhance obstacle category features and improve the recognition accuracy of obstacle categories. At the same time, a monocular ranging method is incorporated during obstacle detection, allowing the distance of the detected obstacles to be determined simultaneously. Experimental results show that the improved model achieves an mAP@0.5 value of 91.4% in evaluation metrics, which is 2% higher than before improvement, with shorter detection time and faster detection speed. The improved model demonstrates better detection and recognition performance, validating its effectiveness.
YOLOv7-Tiny; SimAM; Monocular Distance Measurement.
Simulation Study on Ultra-High Pressure Rupture Disc of Pressure-Controlled Testing Tool
In APR formation testing technology, the ultra-high pressure rupture disc is a core component ensuring the reliability of downhole operations. Aiming at the requirements for performance optimization and precise design of rupture discs under ultra-high pressure downhole conditions, this study adopts Inconel 718 nickel-based alloy as the bursting disc material and establishes a three-dimensional simulation model with reference to the 17.5 ksi rupture disc of OSECO Corporation. The effects of initial thickness S0, arch height H, top thinning thickness t0 and temperature on the stress distribution and rupture characteristics of the bursting disc are systematically analyzed using simulation software. The results show that increasing the initial thickness and arch height can reduce the degree of stress concentration and improve the burst pressure; the top thinning structure can transfer the stress concentration zone from the arch base to the arch crown to achieve controllable rupture, which is consistent with the actual failure morphology; the influence of temperature on burst pressure is mainly reflected by the attenuation of yield strength, and the fitted temperature-burst pressure curve agrees well with the trend of similar products of OSECO. This study verifies the adaptability of Inconel 718 alloy and the rationality of structural design, providing a theoretical basis and technical support for the design optimization and engineering application of ultra-high pressure rupture discs.
APR Testing Tool; Ultra-high Pressure Rupture Disc; Inconel 718; Numerical Simulation; Structural Optimization; Rupture Characteristics.
Study on the Ultimate Drop Height of Fast Reactor Fuel Assemblies
To evaluate the drop resistance safety performance of fast reactor fuel assemblies during operation and handling, determine their safe drop height threshold, and prevent structural integrity and sealing failure caused by accidental drops, drop impact tests at various heights were conducted. By analyzing the variation laws of acceleration and strain responses with drop height, reconstructing the drop dynamic process combined with ANSYS/LS-DYNA numerical simulation, the critical drop height for collapse failure of fuel assemblies was predicted based on the super folding element theory. The results show that the peak acceleration and peak strain increase significantly with the rise of drop height. Plastic deformation occurs at the bottom of the hexagonal wrapper tube when the drop height is 1000 mm, and collapse failure takes place at the drop height of 4050 mm. Finally, the critical drop height for structural failure of fuel assemblies is determined through theoretical analysis, which provides a quantitative safety basis for their operation and layout design.
Fast Reactor Fuel Assembly; Drop Impact Test; Numerical Simulation; Super Folding Element Theory.
Research Progress in Monitoring Arbor Moisture Content via Image Processing Technology: A Case Study of Typical Trees in Central Yunnan
The moisture content of arbor trees is a core indicator that reflects the dryness of forest combustibles and evaluates forest fire risk levels. Traditional methods for measuring moisture content have limitations such as time consumption, strong destructiveness, and difficulty in large-scale popularization. In contrast, image processing technology has gradually become an important method for rapid vegetation moisture monitoring due to its advantages of non-contact, low cost, high efficiency, and easy automated monitoring. This paper systematically reviews the research progress on the inversion of plant moisture content using image processing technology at home and abroad, summarizes the application rules of image features including color, texture and morphology, and reviews the research status of image monitoring for the moisture content of arbor trees and forest combustibles in forestry. The aim is to provide a reference for dynamic forest fire risk monitoring, rapid assessment of combustible moisture content and related academic research in central Yunnan.
Image Processing; Arbor Moisture Content; Forest Combustibles.
Deep Learning-Based Segmentation and Quantification of Metro Shield Tunnel Lining Cracks
To address the issues of insufficient segmentation accuracy and high computational complexity in crack detection of metro shield tunnel linings, a lightweight instance segmentation model named YOLO-LCD based on YOLO11 is proposed. The model introduces StarNet into the backbone to reduce computational cost, constructs a C3k2-S module in the neck to enhance crack feature representation, and replaces traditional concatenation with a Modulation Fusion Module (MFM) to improve multi-scale feature fusion efficiency. Meanwhile, a Lightweight Shared Convolution Detection head (LSCD) is adopted to reduce parameter redundancy. Furthermore, a complete crack extraction and quantification framework is developed by integrating image enhancement, Frangi filtering, and skeleton extraction, enabling automatic measurement of crack length, width, and orientation. Experimental results demonstrate that the proposed model significantly reduces parameters and computational cost while maintaining competitive segmentation accuracy, achieving a favorable balance between accuracy and efficiency and meeting the practical requirements of metro tunnel inspection.
Metro Shield Tunnel; Crack Detection; Instance Segmentation; Lightweight Model; Crack Quantification.
Research on the Influence of Concrete Strength Discreteness on Structural Reliability by 3D Printing
3D-printed concrete is revolutionizing the construction industry through its mold-free manufacturing and high design flexibility. However, its performance variability-caused by factors like manufacturing processes, material properties, and environmental conditions-often leads to structural weaknesses, anisotropic behavior, and unconventional failure modes. While existing research employs discrete medium simulations, quantifying the impact of multi-source variability on structural reliability remains a critical challenge. To address this, this study establishes an analytical framework of "multi-source etiology-reliability impact," aiming to uncover underlying mechanisms. The findings will provide theoretical foundations for developing probabilistic design and code systems for 3D-printed concrete structures.
3D Printed Concrete; Multi-source Genesis; Discreteness; Reliability.
Research on Reliability Improvement of Primary Equipment in Substation
Substation primary equipment is the material basis for power system to realize power transmission and conversion, and its reliability is directly related to the safe and stable operation of power grid and the quality of power supply. In this paper, the reliability improvement of primary equipment in substation is systematically studied. Firstly, the fault status of core equipment is analyzed, and the operation and maintenance dilemma of traditional maintenance mode and intelligent transformation, as well as the constraints of aging equipment, weak basic conditions and insufficient data support are sorted out. Secondly, the key technology system of reliability improvement is constructed from four dimensions: condition monitoring, fault diagnosis and prediction, design and manufacturing optimization and operation and maintenance strategy optimization, covering multi-parameter collaborative monitoring, intelligent fault diagnosis model, digital twin simulation and life cycle cost optimization. Finally, systematic reliability management strategy suggestions are put forward from three aspects: life cycle management, standardization and standardization construction, personnel training and technical exchange, and a closed-loop reliability guarantee mechanism covering the whole process of design, manufacturing, operation and maintenance and retirement is constructed.
Substation; Primary Equipment; Reliability Improvement.
An Optimisation Method for the Micro-Engineering Upgrade of Urban Electric Vehicle Charging Infrastructure based on Queueing Theory and Graph Theory
Addressing key engineering challenges in existing urban areas-such as the mismatch between supply and demand for electric vehicle charging infrastructure, queuing and congestion, and construction-related disturbances to residents-this paper takes Fengrun District in Tangshan City, Hebei Province, as its study area. It proposes a three-tiered, progressive micro-renewal approach comprising ‘macro-queuing theory diagnosis-micro-graph theory optimisation-low-impact construction implementation’, thereby establishing a complete technical closed-loop process ranging from bottleneck identification and precise optimisation to construction implementation. Firstly, by comprehensively utilising KNN, Linear SVM and RBF SVM algorithms, the study systematically identifies user charging behaviour patterns, issues early warnings for facility anomalies and assesses battery health, thereby providing data support for subsequent optimisation. Secondly, an asymmetric double-queue queuing theory model is constructed to conduct a macro-level performance diagnosis of charging stations serving local users in the core area of Fengrun District, accurately identifying and locating bottleneck sites requiring optimisation. Thirdly, by selecting these bottleneck sites and establishing an undirected graph model, the Dijkstra shortest path algorithm is applied to optimise the layout of charging piles and vehicle guidance strategies, thereby achieving a balanced improvement in pile utilisation rates; Furthermore, by integrating key factors affecting user charging costs and construction disruption, we conducted scientific measurement and quantitative analysis to design a low-impact construction plan that integrates Gantt charts, network diagrams and BIM technology, ensuring the efficient implementation of the optimisation plan whilst simultaneously enhancing the user charging experience and the operational efficiency of the construction team. SimPy discrete-event simulation results indicate that, following the application of the method proposed in this paper, the average queuing time at bottleneck sites is reduced by 39.9%-45.5%, users’ average daily charging costs decrease by 15.0%-16.4%. This significantly reduces disruption to surrounding traffic and residents’ daily lives, effectively safeguarding users’ needs for convenient and economical charging whilst significantly improving contractors’ operational efficiency and reducing construction costs and safety risks. The three-tier progressive micro-upgrade method proposed in this paper achieves a closed-loop process spanning regional bottleneck identification, precise on-site optimisation, and construction implementation. It provides a systematic technical pathway and practical reference for the micro-upgrade of charging infrastructure in existing urban areas, effectively balancing the dual benefits for both users and contractors.
Charging Infrastructure; Micro-renovation; Low-impact Construction; Operations Research Models.
Effect of Magnesium Microalloying on Microstructural Strengthening and Mechanical Properties of Beryllium Bronze
To address the critical bottlenecks of traditional beryllium bronze, such as poor strength-ductility synergy and susceptibility to high-temperature softening caused by its reliance on a single precipitation strengthening mechanism, a 0.08% Mg micro-alloying modification strategy is proposed in this study. By systematically investigating the effects of aging treatments on the microstructure, as well as the room-temperature and medium-to-high-temperature mechanical properties of the Mg-containing beryllium bronze, the strengthening role of Mg and the underlying mechanisms for microstructural stabilization are thoroughly revealed. The results indicate that the introduction of trace amounts of Mg yields a significant grain refinement effect, reducing the average grain size of the alloy from 25~40 μm to 15~25 μm. The Mg atoms exhibit a globally uniform solid solution state without grain boundary segregation. Without interfering with the normal nucleation of the γ'-Be₂Cu precipitates, a ternary synergistic strengthening system comprising "grain refinement, solid solution, and precipitation" is successfully established. Regarding the room-temperature mechanical properties, after a peak aging treatment at 330 °C for 2 h, the tensile strength of the alloy reaches 1211 MPa, while the elongation is robustly maintained at 8.98%. This strength-ductility synergy is significantly superior to that of traditional Mg-free beryllium bronzes. In terms of medium-to-high-temperature performance, tests demonstrate that after holding at 300 °C for 15 min, the tensile strength remains as high as 1119 MPa with an outstanding strength retention rate of 92.4%, exhibiting exceptional high-temperature thermal stability. Notably, when benchmarking the high-temperature performance against the commercial C17200 alloy, it is found that the uniformly dissolved Mg atoms kinetically suppress the coarsening rate of the strengthening precipitates through a strong "solute drag" effect. Within the core service temperature range of ≤300 °C, the microstructural stabilization efficacy provided by merely 0.08% of inexpensive Mg perfectly achieves functional equivalence to that of 0.2%~0.4% of costly and scarce strategic cobalt (Co). While significantly enhancing the comprehensive performance of beryllium bronze, this study provides a novel pathway to overcome the limitations of high-cost cobalt resources and to develop highly cost-effective, heat-resistant copper-beryllium alloys.
Beryllium Bronze; Magnesium Microalloying; Aging Process; Microstructure; Mechanical Properties; Strength-Plasticity Matching; High-Temperature Stability.
Mechanical Performance and Feasibility Study of Steel Plate-Bolted Glulam Trusses
To promote the application of engineered timber in medium- and long-span structural systems, this paper investigates the mechanical performance and feasibility of steel plate-bolted glulam trusses. The proposed structural form combines glulam members with double-sided steel gusset plates and through bolts, forming a mechanical connection system capable of transferring axial force, shear force, and a certain degree of bending moment at the joints. The material compatibility of glulam, structural steel plates, and dowel-type bolts is discussed first, followed by an analysis of the truss configuration, load-transfer mechanism, preliminary experimental response, numerical simulation strategy, and design feasibility. The results indicate that the steel plate-bolted connection can provide a clear load path, reliable assembly conditions, and improved joint restraint for glulam trusses. Preliminary static loading observations show that the failure process is mainly governed by joint slip, local timber embedment, splitting around bolt holes, bolt bending, and local cracking of critical members, while the global truss response retains an evident staged development. Refined numerical modelling can effectively reproduce the overall load-displacement trend and reveal stress concentration near bolts and steel plates. Theoretical interpretation based on dowel-type connection yielding and joint bending resistance further supports the feasibility of this structural form. Overall, steel plate-bolted glulam trusses show good potential for green building structures, especially where structural efficiency, prefabrication, maintainability, and low-carbon material use are required.
Steel Plate-Bolted Connection; Glulam Truss; Steel Gusset Plate; Dowel-Type Fastener; Mechanical Performance; Numerical Simulation; Green Timber Structure.
Research on Structural Design and Optimization of Lightweight Unmanned Aerial Vehicles
With the rapid advancement of aerospace technology, lightweight unmanned aerial vehicles (takeoff weight ≤7kg) have gained widespread application across multiple fields-including military reconnaissance, agricultural crop protection, geographic surveying, and disaster relief-due to their compact size, high maneuverability, low cost, and ease of operation. Structural design, as a core component of their development, directly determines flight performance, payload capacity, endurance, and operational reliability. This paper explores structural design and optimization for lightweight UAVs. It outlines the research background and significance, reviews domestic and international research status, defines research content and technical approaches, and focuses on key technologies including composite material application, biomimetic structural design, integrated and modular design, and multidisciplinary optimization. The effectiveness of optimization solutions is validated through a combination of theoretical analysis, numerical simulation, and experimental verification. Finally, it proposes optimization directions and development trends to support related research and engineering practice.
Lightweight UAV; Structural Design; Composite Materials; Bionic Design; Multidisciplinary Optimization.
Exploration of Low-Power Communication Technologies in Passive Internet of Things (IoT)
Passive IoT enables battery-free communication by harvesting ambient energy, offering a revolutionary pathway for building green and sustainable massive IoT networks. This paper explores the principles of key low-power technologies such as ambient backscattering and energy harvesting, and analyzes their application value and challenges in scenarios including retail, logistics, and industrial monitoring. The research indicates that this technology will drive the evolution of IoT towards ultra-low cost and maintenance-free operation. However, its large-scale adoption still depends on overcoming bottlenecks related to communication range and the standard ecosystem.
Passive IoT; Low-power Communication; Ambient Backscattering; Radio Frequency Identification (RFID); Energy Harvesting.
Study on Similar Materials for Tunnel Lining and Sand in Water-Rich Scale Model Tests
Addressing the challenge of similar material selection in fluid-solid coupling physical model tests for water-rich tunnels, this study systematically investigates the mix proportion optimization of similar materials for tunnel lining and sand. Through sequential testing, two lining similar material schemes based on gypsum and micro-concrete were compared. The results indicate that gypsum-based materials, although capable of matching scaled mechanical parameters, exhibit poor forming integrity and significant water softening, making them unsuitable for water-involved environments. The optimized micro-concrete proportion demonstrates good compactness and impermeability, with a strength retention rate of approximately 70% after water immersion, rendering it more adaptable to water-rich conditions. For sand similar materials, a practical scaled-down strategy of "parameter substitution" was proposed to maintain soil characteristics while strictly controlling particle gradation to ensure key parameters such as friction angle and permeability coefficient. Ultimately, a mixing scheme of river sand, barite powder, and glass fiber was selected, successfully simulating the density, internal friction angle, and permeability coefficient of the prototype medium-coarse sand layer. This research establishes a design method for similar materials in water-rich fluid-solid coupling model tests, with permeability coefficient and hydro-stability as primary control indices, providing reliable technical references for physical simulation of similar projects.
Similar Materials; Mix Proportion Experiment; Model Test; Permeability Coefficient; Tunnel Surrounding Rock.
Design of Lightweight Composite Thermal Insulation Structural Components for Civil Air Defense Projects
This study involves a lightweight composite insulation structural component for civil air defense construction, aiming to solve the problems of alignment accuracy control and leakage prevention at the board joints during the installation of insulation boards. This structural component includes a shell, positioning module, sensing module, anti-misalignment module, closure module and leak-proof module. It assists in positioning and installing adjacent insulation boards and senses their alignment in real time. When the insulation board is misaligned, the anti-misalignment module automatically blocks the screw holes and forcibly interrupts the installation process. Fixation can only be carried out when the alignment meets the standard and the anti-misalignment piece is detached from the through hole, thereby ensuring the positional accuracy after installation. In addition, the structural components adopt the TG mortise and tenon type butt joint method. Compared with the flat head butt joint, it can effectively slow down the seepage of liquid through the board joints. Combined with the anti-leakage module, it can absorb the already seeped liquid, maximizing the delay of liquid erosion on the insulation system and extending the service life of the entire system. The present invention provides a reliable solution for the rapid, precise and durable installation of insulation structures in civil air defense projects and other construction fields by integrating positioning, error-proofing and leak-proofing functions.
Civil Air Defense Project; Energy Conservation and Emission Reduction; Insulation Board; Foolproof and Leak-Proof; Installation Accuracy.
Hourly Heat Load Prediction for District Heating Systems based on Long Short-Term Memory Network
In conjunction with the rapid progress in intelligent heating technology, heat load-based prediction and on-demand heating have been considered as the most important factor for the realization of optimized regulation in a centralized system. The prediction of heat load in heating systems will be useful for the optimization of automatic control and green heating. But traditionally applied methods are less effective and vulnerable to noise, hence they cannot meet the demands of industrial practice. Recently, deep learning techniques have been intensively researched and used in order to extract meaningful features from the data and construct models. LSTM model has proven superior compared to other approaches in terms of performance. In this regard, the purpose of this study is to use a deep learning method of Long Short-Term Memory Network for the accurate heat load prediction in DHSs in order to reduce the waste of resources.
Heat Load Prediction; DHSs; Deep Learning; LSTM Model.
Esterified Starch-derived Hard Carbon Anodes as High Initial Coulombic Efficiency Anode Material for Sodium-ion Batteries
The widespread adoption of sodium-ion batteries (SIBs) depends heavily on the development of affordable and renewable hard carbon (HC) anodes. While existing HC synthesis methods often rely on complex chemical modifications to boost electrochemical properties, these complicated processes hinder large-scale industrial application. To address this issue, our study presents a cost-effective and green HC material derived from an esterified cassava starch precursor. We comprehensively evaluated how this specific precursor influences the material's microstructural evolution, surface oxygen functionalities, and over all Na-ion storage mechanisms. During electrochemical evaluation, the optimized MA-SCHC-20 anode delivered an impressive reversible capacity of 356.5 mAhg-1 at 0.1 C and achieved a remarkable initial coulombic efficiency (ICE) of 90.2%. Even at a high rate of 5 C, it maintained a robust capacity of 195.7 mAhg-1. Furthermore, multi-scan-rate cyclic voltammetry was employed to elucidate the underlying sodium storage kinetics.
Sodium-ion Battery; Hard Carbon; Starch; Malay Anhydride.
Synergistic Mechanisms of Carbonated Bayer Red Mud in Enhancing Chloride Binding Capacity of Cement-Based Materials
Bayer red mud (BRM), a solid waste, can be effectively treated through carbonation to decrease its alkalinity and improve its reactivity.This study introduces carbonated Bayer red mud (CBRM) as a supplementary cementitious material into the cement system, systematically revealing its influence mechanism on chloride ion (Cl-) binding behavior and performance optimization pathways in marine environments. The evolution of phase composition and microstructural characteristics during the reaction process of the composite cementitious material system (OPC-CBRM) was analyzed using XRD, TG/DTG, and scanning electron microscopy (SEM).The results showed that compared to ordinary Portland cement paste, the composite cement paste incorporating 30% CBRM exhibited increases of 40% and 68% in total bound chloride and chemically bound chloride contents, respectively, while the physically bound chloride content decreased by 12%.OPC-CBRM generates Friedel's salt (AFm-Cl) efficiently through the release of reactive Al³+ (secondary pozzolanic reaction) and the conversion of calcium carbonate to monocarbonate aluminate (AFm-CO3), followed by Cl-/CO32- ion exchange. The Freundlich model demonstrates a higher goodness-of-fit than the Langmuir model for describing the relationship between free chloride and bound chloride.The presence of Mg2+ and Ca2+ promotes the decomposition of AFt to form gibbsite. Specifically, Ca2+ increases chemically bound chloride content by 24%, while Mg2+ increases it by 13%. Sulfate attack reduces chemically bound chloride content: compared with Na2SO4 attack, MgSO4 attack results in a 61% reduction, and CaSO4 attack leads to a 60% reduction. It should be noted that CBRM incorporation reduces the compressive strength of cement-based materials, with strength decreasing progressively as CBRM content increases, primarily attributed to reduced C-S-H formation, retarded hydration by Na2O, and insufficient filler effect of CaCO3. This study provides theoretical foundation for red mud resource utilization and the design of highly durable marine cementitious materials, achieving the dual objectives of "solid waste management for corrosion control" and "carbon sequestration, " which is of significant importance for extending the service life of marine engineering structures.
Carbonation; Bayer Red Mud; Chloride Binding; Friedel's Salt; Marine Engineering Materials.