bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface populations as a model for the distance-dependence of the interfacial refractive index
Authors: Yang Peter , Kumarasiri Aruna , Hore Dennis
Published: August 2024

Vibrational sum frequency spectra provide information about interfaces that is sensitive to the orientation of molecules, their electronic environment, and the local electric fields. Here, we use molecular dynamics simulations in order to study a surfactant, para-cyanophenol, at the air–water interface. The volume fractions of water and the organic surfactant are considered at various points over the nanometer-scale region in a Lorentz–Lorenz model. We find that the calculated ratios of nonlinear susceptibility tensor elements are in agreement with experimental data only when this depth profile was considered. We also use these data to evaluate the ratio of the C–N hyperpolarizability tensor elements in the interfacial region.
Scale law analysis of the curved boundary layer flow induced by constant flux heating around a horizontal cylinder for a Prandtl number larger than 1 fluids
Authors: Ma Zhengping , Liu Yang
Published: August 2024

The convective boundary layer flow on the external surface of an iso-flux heated horizontal cylinder is investigated in this study. Under the premise of a Prandtl number Pr larger than 1, numerical simulations are conducted over a wide range of flow parameters, including variations in Rayleigh and Prandtl numbers. The present simulations demonstrate that similar to the extensively studied flat-plate boundary layer flows, development of the present curved boundary layer also consists of three states: an initial growth state, a transitional state, and a steady state. Scale laws of the characteristic velocity, boundary layer thickness, and Nusselt number Nu describing the initial and steady states are determined based on the calculated cases. The comparison suggests that the proposed scale laws could satisfactorily quantify the boundary layer flow, and the corresponding regression constants R2 are all above 0.995. The results indicate that the present characteristic velocity of the curved boundary layer depends both on time and streamwise location. Hence, the flow of the curved boundary layer follows a two-dimensional initiation, which is different from the one-dimensional growth of the flat-plate boundary layer in the initial state. The obtained scale law also indicates that the characteristic velocity of the boundary layer flow maximizes at π/2, but its thickness is circumferential location independent. In the steady state, the maximum tangential velocity occurs at approximately the central angle θ = 7π/9, and we show that this value is independent of the governing parameters.
A density of states-based approach to determine temperature-dependent aggregation rates
Authors: Trugilho L. F. , Auer S. , Rizzi L. G.
Published: August 2024

Here, we establish an approach to determine temperature-dependent aggregation rates in terms of thermostatistical quantities, which can be obtained directly from flat-histogram and statistical temperature algorithms considering the density of states of the system. Our approach is validated through simulations of an Ising-like model with anisotropically interacting particles at temperatures close to its first-order phase transition. Quantitative comparisons between the numerically obtained forward and reverse rates to approximate analytical expressions corroborate its use as a model-independent approach.
Adaptive accelerated reactive molecular dynamics driven by parallel collective variables overcoming dimensionality explosion
Authors: Zhou Rui , Bao Luyao , Bu Weifeng , Zhou Feng
Published: August 2024

ReaxFF reactive molecular dynamics has significantly advanced the exploration of chemical reaction mechanisms in complex systems. However, it faces several challenges: (1) the prevalent use of excessively high temperatures (>2000 K), (2) a time scale considerably shorter than the experimental timeframes (nanoseconds vs seconds), and (3) the constraining impact of dimensionality growth due to collective variables on the expansiveness of research systems. To overcome these issues, we introduced Parallel Collective Variable-Driven Adaptive Accelerated Reaction Molecular Dynamics (PCVR), which integrates metadynamics with ReaxFF. This method incorporates bond distortion based on each bond type for customized Collective Variable (CV) parameterization, facilitating independent parallel acceleration. Simultaneously, the sampling was confined to fixed cutoff ranges for distinct bond distortions, effectively overcoming the challenge of the CV dimensionality explosion. This extension enhances the applicability of ReaxFF to non-strongly coupled systems with numerous reaction energy barriers and mitigates the system size limitations. Using accelerated reactive molecular dynamics, the oxidation of ester-based oil was simulated with 31 808 atoms at 500 K for 64 s. This achieved 61% efficiency compared to the original ReaxFF and was ∼37 times faster than previous methods. Unlike ReaxFF’s high-temperature constraints, PCVR accurately reveals the pivotal role of oxygen in ester oxidation at industrial temperatures, producing polymers consistent with the sludge formation observed in ester degradation experiments. This method promises to advance reactive molecular dynamics by enabling simulations at lower temperatures, extending to second-level timescales, and accommodating systems with millions of atoms.
Electronic structure and magnetothermal property of H-VSe2 monolayer manipulated by carrier doping
Authors: Jiang Jun-Kang , Wu Yan-Ling , Geng Hua-Yun , Chen Xiang-Rong
Published: August 2024

High-performance and stable spintronic devices have garnered considerable attention in recent years. Based on first-principle and Monte Carlo calculations, we demonstrate that under reasonable carrier doping, H-VSe2 exhibits 100% spin polarization, a magnetic anisotropy energy of 581 μeV, a tunable easy-axis, and a Curie temperature of 330 K. Moreover, Dzyaloshinskii–Moriya interactions in H-VSe2 and magnetic hysteresis loops are determined theoretically for the first time, which provides more precise and comprehensive descriptions of its magnetic properties under finite temperatures and external magnetic field. This work suggests that H-VSe2 is a powerful candidate for spintronic devices, and it provides solid theoretical support for future experiments.
Domino-like water film manipulation with multifunctionality
Authors: Yang Pengyu , Yin Kai , Li Xun , Song Xinghao , Wang Lingxiao , Pei Jiaqing , Wu Tingni , Huang Yin , Awan Saif U. , Khalil Ahmed S. G.
Published: August 2024

Domino effect is widely known and intuitively understood. Although the concept is frequently used, a few works combine it with liquid manipulation. Liquid manipulation is essential in many fields; however, large-scale liquid manipulation using minimal forces is still a challenge. Here, we show a domino-like liquid manipulation process triggered by wind on heterogeneously wettable surfaces. This effect was demonstrated using velocities of wind between 2.2 and 3.0 m/s on structured surfaces containing water film thickness in the range of 2.5–4.5 mm. The domino dewetting surfaces were shown on various patterned designs with 32–224 mm in length; however, under ideal conditions, the effect could be infinitely transmissible. Such a concept might apply to long-distance directional transportation of floats, and bed bottom dust cleaning. Other designs, such as a branched tree structure, can drive larger objects, and remote circuit interrupters were shown. This method provides an approach for manipulation of water movement by tiny forces triggered toward multifunctionality.
Versatile, modular, and customizable magnetic solid-droplet systems
Authors: Sun Mengmeng , Wu Yingdan , Zhang Jianhua , Zhang Hongchuan , Liu Zemin , Li Mingtong , Wang Chunxiang , Sitti Metin
Published: August 2024

Magnetic miniature robotic systems have attracted broad research interest because of their precise maneuverability in confined spaces and adaptability to diverse environments, holding significant promise for applications in both industrial infrastructures and biomedical fields. However, the predominant construction methodology involves the preprogramming of magnetic components into the system’s structure. While this approach allows for intricate shape transformations, it exhibits limited flexibility in terms of reconfiguration and presents challenges when adapting to diverse materials, combining, and decoupling multiple functionalities. Here, we propose a construction strategy that facilitates the on-demand assembly of magnetic components, integrating ferrofluid droplets with the system’s structural body. This approach enables the creation of complex solid-droplet robotic systems across a spectrum of length scales, ranging from 0.8 mm to 1.5 cm. It offers a diverse selection of materials and structural configurations, akin to assembling components like building blocks, thus allowing for the seamless integration of various functionalities. Moreover, it incorporates decoupling mechanisms to enable selective control over multiple functions, leveraging the fluidity, fission/fusion, and magneto-responsiveness properties inherent in the ferrofluid. Various solid-droplet systems have validated the feasibility of this strategy. This study advances the complexity and functionality achievable in small-scale magnetic robots, augmenting their potential for future biomedical and other applications.
Analyte-dependent Rabi splitting in solid-state plexcitonic sensors based on plasmonic nanoislands strongly coupled to J-aggregates
Authors: Garcia John Carlo , Wilson Ethan Alex , Aggarwal Dipesh , Rajashekhar Harshitha , Vrushabendrakumar Damini , Shankar Karthik
Published: August 2024

A key challenge in the field of plexcitonic quantum devices is the fabrication of solid-state, device-friendly plexcitonic nanostructures using inexpensive and scalable techniques. Lithography-free, bottom-up nanofabrication methods have remained relatively unexplored within the context of plexcitonic coupling. In this work, a plexcitonic system consisting of thermally dewetted plasmonic gold nanoislands (AuNI) coated with a thin film of J-aggregates was investigated. Control over nanoisland size and morphology allowed for a range of plasmon resonances with variable detuning from the exciton. The extinction spectra of the hybrid AuNI/J-aggregate films display clear splitting into upper and lower hybrid resonances, while the dispersion curve shows anti-crossing behavior with an estimated Rabi splitting of 180 eV at zero detuning. As a proof of concept for quantum sensing, the AuNI/J-aggregate hybrid was demonstrated to behave as a plexcitonic sensor for hydrochloric acid vapor analyte. This work highlights the possibility of using thermally dewetted nanoparticles as a platform for high-quality, tunable, cost-effective, and scalable plexcitonic nanostructures for sensing devices and beyond.
Response solutions for elliptic-hyperbolic equations with nonlinearities and periodic external forces
Authors: Dong Yingdu , Li Xiong
Published: August 2024

In this paper, we focus on the existence of response solutions, i.e. periodic solutions with the same frequencies as the external forces, for elliptic-hyperbolic partial differential equations with nonlinearities and periodic forces. The main tools are Lyapunov–Schmidt reduction and Nash–Moser iteration scheme, both of which have demonstrated success in hyperbolic scenarios. At each step of the iteration, the Galerkin approximation of the equation is solved. The new issue is that the spectral theory of the generalized Sturm–Liouville problem is employed, which also introduces new difficulties for estimations at each step. Under appropriate non-resonance conditions on the frequency, the existence of response solutions for the model will be established.
Quantum illumination and quantum radar: a brief overview
Authors: Karsa Athena , Fletcher Alasdair , Spedalieri Gaetana , Pirandola Stefano
Published: August 2024

Quantum illumination (QI) and quantum radar have emerged as potentially groundbreaking technologies, leveraging the principles of quantum mechanics to revolutionise the field of remote sensing and target detection. The protocol, particularly in the context of quantum radar, has been subject to a great deal of aspirational conjecture as well as criticism with respect to its realistic potential. In this review, we present a broad overview of the field of quantum target detection focusing on QI and its potential as an underlying scheme for a quantum radar operating at microwave frequencies. We provide context for the field by considering its historical development and fundamental principles. Our aim is to provide a balanced discussion on the state of theoretical and experimental progress towards realising a working QI-based quantum radar, and draw conclusions about its current outlook and future directions.
Prediction of novel layered indium halide superconductors
Authors: Yuan 袁 Zhi-Hong 志红 , Meng 孟 Jing-Jing 静静 , Liu 刘 Rui 瑞 , Zheng 郑 Peng-Yu 鹏宇 , Yin 殷 Zhi-Ping 志平
Published: August 2024

We design two new layered indium halide compounds LaOInF2 and LaOInCl2 by means of first-principles calculations and evolutionary crystal structure prediction. We find both compounds crystallize in a tetragonal structure with P4/nmm space group and have indirect band gaps of 2.58 eV and 3.21 eV, respectively. By substituting O with F, both of them become metallic and superconducting at low temperature. The F-doping leads to strong electron–phonon coupling in the low-energy acoustic phonon modes which is mainly responsible for the induced superconductivity. The total electron–phonon coupling strength are 1.86 and 1.48, while the superconducting transition temperature (T
c) are about 7.2 K and 6.5 K with 10% and 5% F doping for LaOInF2 and LaOInCl2, respectively.
Dynamic voltage safety measurement and assessment index considering short-term voltage stability
Authors: Zhang Yangnan , Sui Lihui
Published: August 2024

At present, most of the short-term voltage stability criteria used in various power grids are based on voltage waveform, but these criteria can only determine whether the voltage is stable in the power system, but cannot give the relative degree of voltage stability. To evaluate and further plan reactive power reserves in power systems, a criterion for evaluating the short-term voltage stability (STVS) of power systems is needed. In this paper, a Dynamic Voltage Safety Measurement and Assessment Index (DVSMAI), which is based only on bus voltage data, is proposed, consisting of three indexes. They are the low voltage recovery component, the oscillation degree component, and the steady-state recovery component. Each component can correspond to the response of the bus voltage in the transient process, so the voltage waveform in the transient process can be described more comprehensively. The size of the index can fully quantify the voltage stability and safety in various cases, and the generalization ability is strong.
Calculation of cable core temperature and cooling method of submarine cable
Authors: Zeng Xiancheng , Luo Yi , Liu Zhipeng
Published: August 2024

The cooling condition of the landfalling segment of the submarine cable is not good, so it is of prime importance to consider its temperature dependence. To investigate the cooling performance of circulating spraying of cold-water pipe, a transient thermal path model and a three-dimensional mathematical model of multi-physical coupling fields in the landfalling segment of submarine cable were established, and a cooling device platform was built. The temperature dependence of every structural floor of submarine cable under two models was discussed and contrasted, and the cooling performance of the submarine cable cooling device was studied.
Reactive power optimization for power distribution networks using mixed-integer Second-order cone programming
Authors: Xiang Xiaojing , Gao Shihong
Published: August 2024

The integration of a large number of Distributed Resources (DR) into the power distribution network presents significant challenges to the system’s reactive power and voltage control. This paper comprehensively considers the impacts of network losses, curtailment of renewable energy, and user electricity consumption experiences, and establishes a reactive power optimization model for distribution networks with multiple types of distributed resources. Initially, complex relationships among power flow variables are approximated by linear expressions, transforming the power flow model into a Second-order Cone Programming (SOCP) formulation. Subsequently, quadratic nonlinear terms in the constraints are linearized through the use of auxiliary variable methods. Ultimately, the effectiveness of the proposed model is verified on the IEEE BUS-33 system, with an analysis conducted on the influence of distributed resource capacity, demand response weighting coefficients, and demand response levels on system operation. The study concludes that before the absorption capacity limit of the system, an increase in distributed resource capacity not only reduces system losses but also enhances the user’s electricity consumption experience. However, beyond this absorption capacity limit, further increases in distributed resource capacity not only lead to increased system losses but also result in renewable energy curtailment, thereby causing resource waste.
Research on harmonic power flow calculation method of distribution network with large-scale distributed grid-connected inverter
Authors: Jiang Feng , Ding Jinjin , Xiao Huafeng
Published: August 2024

To calculate the harmonic power flow of the distribution network with large-scale distributed grid-connected inverter, this paper first establishes the harmonic source model based on the grid-connected control strategy and modulation mode of inverters, then establishes the harmonic network according to the parameters and harmonic frequency of the distribution network so as to calculate the high-order harmonic power flow in the distribution network. The accuracy and practicability of the proposed method are verified by the simulation results of Matlab/Simulink platform for a distribution network model with multiple distributed grid-connected inverters.
Intraday optimal scheduling method for microgrid in small sample scenarios
Authors: Zhao Huiting , Meng Ming
Published: August 2024

A deep reinforcement learning method for micro-grid optimal scheduling based on data augmentation was proposed to solve the problem of insufficient training data of deep reinforcement learning for micro-grid optimal scheduling in small sample scenarios. First, the micro-grid optimal scheduling model was transformed into a decision model suitable for deep reinforcement learning. Moreover, the near-end strategy optimization algorithm was used to solve the model. Then, a new energy power generation scenario generation method based on the Wasserstein adversarial generative network with gradient penalty was proposed to expand the training set of deep reinforcement learning.
A multi-feature fusion algorithm for single-phase high-impedance ground fault line selection in distribution networks based on Hilbert-Huang transform
Authors: Li Jinyao , Wu Shouyuan , Gao Lixue
Published: August 2024

High-impedance faults in distribution networks are characterized by steady-state features, making them difficult to identify. A Hilbert-Huang Transform (HHT) analysis technique is utilized in this paper to identify fault lines. The Intrinsic Mode Function (IMF) components, derived from the decomposition of zero-sequence currents in the aftermath of a fault, are then used to generate characteristic values through a time-frequency energy matrix and similarity measures. In this paper, a single-phase high-impedance ground fault line selection algorithm is proposed for distribution networks. Additionally, the first-order IMF is subjected to a Hilbert transform to obtain HHT spectral peak values, which are then combined with the peak values of zero-sequence currents to form a multi-feature fusion criterion for fault line selection. Verification of the efficacy of the suggested fault line selection technique is accomplished using simulation data from a single-phase ground fault model in a distribution network.
Optimization of cogging torque in outer rotor Permanent Magnet Synchronous Motors based on particle swarm algorithm
Authors: Wang Sen , Wang Wenshuo , Li Jiaxin , Tang Chong , Chen Xiaohong
Published: August 2024

To mitigate issues like torque ripple and the accompanying vibration and noise caused by high cogging torque in Permanent Magnet Synchronous Motors (PMSMs), this research adopts a strategy of employing magnets with unequal thickness in the motor’s design. By integrating Ansys finite element analysis with the Central Composite Design (CCD) methodology for experiments, it gathers critical response data. These data points underpin the development of a second-order response surface regression model for outer rotor PMSMs. Utilizing this model, the research aims to minimize the cogging torque by optimizing the motor’s key structural parameters through Particle Swarm Optimization (PSO), finding the optimal parameter set. The results from finite element simulations confirm that this approach significantly reduces cogging torque, achieving effective torque optimization and contributing to smoother motor operation.
Design of rooftop photovoltaic power generation system
Authors: Wen Fawei , Wang Yufang
Published: August 2024

The research was conducted on an urban community rooftop, with the photovoltaic power generation system as the focus. PVsyst software was utilized to simulate the project’s power generation through design and simulation methods. Additionally, 3D models of the roof and photovoltaic modules were created using SketchUp software for analysis and optimization purposes. The simulation results demonstrate that the optimized rooftop photovoltaic system yields superior power generation benefits, providing valuable insights for promoting new energy generation modes such as solar energy utilization and photovoltaic building integration.
Partitioned model predictive control of LiU-Diesel engine air path based on recursive least squares
Authors: Nie Zhiwei
Published: August 2024

Modern diesel engine air-path systems operate the Variable Geometry Turbocharger (VGT) and Exhaust Gas Recirculation (EGR) to track set points for intake manifold pressure, as well as exhaust gas recirculation rate. This presents a challenging canonical case as it describes a highly non-linear multi-input multi-output (MIMO) system. This paper provides an examination of the development procedure for a segmented linear Model Predictive Controller (MPC) based on a data-driven approach. Leveraging the concept of linearization, we develop a series of computationally efficient prediction models, identified based on transient response data generated from the mean model LiU-Diesel. A series of local prediction models constitute a Linear Parameter-Varying (LPV) model covering the entire engine operating region. Subsequently, based on the LPV model, we design and validate a rate-based MPC. The results demonstrate that the MPC designed based on the data-driven LPV model is able to track specified set points and satisfy constraints on states and control.
Research on the speed control system of brushless DC motor based on fuzzy PID control
Authors: Ma Ruzhuo , Li Xiang , Li Yahui
Published: August 2024

This paper presents a fuzzy PID controller for operating the BLDCM speed control system. The controller is built to address the inadequacies of PID controller in real-world applications where substantial model uncertainty and nonlinear components are present. The controller structure, fuzzy rules, and affiliation function were designed based on the current situation. A model of the BLDCM is established, and simulation tests are conducted to evaluate dynamic response and anti-interference capabilities. These tests are compared with results from both the fuzzy logic controller (FLC) and the PID controller. Comparing the developed controller to the other two control techniques, the simulation results suggest that it enhances the anti-interference capabilities of the system and improves both its dynamic and static response performance.
Sliding mode control of dual active bridge converter based on hyperbolic tangent function
Authors: Gu Junjie , Pan Sanbo
Published: August 2024

A sliding mode control (SMC) based on hyperbolic tangent function (HTF) is proposed for dual active bridge (DAB) converters to improve the voltage stabilization performance of output voltage. SMC has gained widespread utilization due to its robustness and its ability to enhance the dynamic performance of nonlinear systems. Nevertheless, the traditional SMC has the problem of buffeting and tracking performance degradation. The SMC based on HTF combines the advantages of SMC and suppresses the buffeting problem. Therefore, the stability and robustness of the output voltage are improved, and accurate reference voltage tracking is realized. To accomplish this objective, a mathematical model of the DAB converter is initially formulated, grounded in the dynamic equation of the output voltage and the power transfer equation, which is taken as the model equivalent part in SMC. At the same time, HTF is used as the switching part and the equivalent part of the model to compare the displacement, and the stability of the control method is established through rigorous analysis using the Lyapunov stability criterion. In the end, in the Matlab-Simulink environment, the proposed SMC based on HTF is simulated and verified.
Optimization design of voltage regulation ring parameters for 1100 kV DC voltage ratio standard equipment based on FCC neural network
Authors: Gao Yin , Gao Ran , Wang Chao , Li Minlong , Shi Jie , Han Gujing
Published: August 2024

The surface electric field strength directly affects the accuracy of voltage measurement in DC voltage ratio standard devices. The auxiliary device known as the voltage regulation ring effectively reduces the surface electric field strength. Therefore, optimizing the voltage regulation ring’s structural characteristics is crucial for decreasing the electric field strength and enhancing the device’s accuracy. This study initially develops a functional engineering simulation model for the device that standardizes the ratio of DC voltages, employing finite element simulation software. Adjustments are made within a feasible range to compute the electric field strength along the surface of the voltage regulation ring, constructing a dataset. Subsequently, an FCC neural network model is constructed to capture the correlation between different parameters of the voltage regulation ring and the maximum surface electric field strength, yielding a relationship model. Finally, the design of the voltage regulation ring is optimized within a finite range using the constructed FCC neural network model to obtain parameters for minimum field strength. Experimental results indicate that under optimal conditions, the minimum electric field strength is 10051.4883 V/cm, effectively reducing the surface electric field strength of the DCVRS device, and provide a reliable and useful design methodology for equipment selection.
Compressible polybenzoxazine high-strength aerogel with a linear structure for thermal insulation
Authors: Long Xin , Xue Ji , Qin Jianan , Tang Jubo , Bi Linnan , Lin Ying , Wei Xiongbang , Liao Jiaxuan
Published: August 2024

The vulnerable structures have been the biggest barrier to the progress and use of aerogels, making it impossible to use aerogels alone in practical environments. The reversible sacrificial hydrogen bonding system in polybenzoxazine can greatly affect the strength function, providing a new approach for designing high-strength aerogels. We achieve a long-chain structured benzoxazine monomer as a precursor and a polybenzoxazine aerogel with excellent mechanical performance. The aerogel achieves a high compression strength (18.8 MPa) and a high fracture strain (78.0 %) at a 0.252 g/cm3 density. Furthermore, the aerogel also exhibits a low room temperature heat conductivity coefficient (0.03343 W/(m·K)) and hydrophobicity (water contact angle of 142.7°), demonstrating its high potential for use in the fields of construction, industry, space flight aircraft, etc.
Performance analysis on VPTIG repair welding joint of 2219 aluminum alloy
Authors: Li Xian , Song Yonglun , Lu Zhenyang
Published: August 2024

When the welded joint of 2219 aluminum alloy has defects, the high-frequency VPTIG is used for welding repair. The mechanism of control is proposed for the repair welding joint, and the process route for satisfying the repair welding joint of 2219-T87 aluminum alloy is formulated to reduce the influence of overall performance on the joint local repair welding position. The research results show that the DC-EN of VPTIG coupled to pulse current at a frequency of 20-25 KHZ is helpful to restrain the metallurgical defects such as pores and refine the grain of the fusion zone, to ensure the comprehensive performance of the repair welding joint.
The analysis and simulation of fracture behavior of fused quartz under dynamic loading
Authors: Duan Wenbo , Zhao Bingyao , Zhou Ping , Guo Dongming
Published: August 2024

Fused quartz is widely utilized across various industries due to its superior performance. However, its brittleness often leads to fracture occurrences under variable external loads during processing or usage, making the investigation of its dynamic mechanical properties and fracture mechanisms crucial. In this study, the fracture strength variations of fused quartz under different loading rates were obtained through strength experiments. It was observed that when the velocity is below 2 mm/min, the loading rate has little influence on fracture strength. And when the velocity exceeds 2 mm/min, fracture strength rises with the increase in velocity. According to the fitted fracture strength-strain rate curve, a modified peridynamic failure criterion was developed to simulate the fracture process under different loading speeds. The simulated fracture morphology closely matched experimental results and the error in fracture load values is less than 8%. It validates the accuracy of the simulation. Additionally, it was found that the displacement values at the moment of fracture under different loading rates were relatively similar. It indicated that higher speeds result in greater loading energy, thus leading to the generation of more cracks and fragments. This study provides theoretical support and reference for understanding the fracture behavior of fused quartz.
Analysis of the reasons for the fracture of the heat-engine plant turbine vane of the power plant feedwater pump
Authors: Gao Jun , Xie Liming
Published: August 2024

The turbine of a 350MW thermal power unit’s feedwater pump in the Mengxi region experienced blade fracture and failure during operation. To identify the cause of blade fracture, comprehensive testing and analysis were conducted on the fractured blade using experimental methods such as macroscopic analysis, chemical make-up analysis, mechanical property testing, microstructure testing, and SEM micro area analysis of the fracture surface. The results indicate that the inner shoulder of the first tooth of the blade root is at a 90° right angle and belongs to the weak part of stress concentration. The steam of this unit contains Cl-, which poses a significant risk to blade materials. Corrosive Cl- accumulates at the inner arc shoulder of the blade root long and forms tensile stress together with the static and dynamic loads during blade operation, leading to the initiation of SCC microcracks in this area. Under the long-term cyclic excitation stress generated by the high-speed rotation of the rotor, the source of stress corrosion cracks propagates in a fatigued manner, resulting in severe fracture of the blade.
Experimental study on the high-velocity impact resistance of Vitrimer-based carbon fiber composites
Authors: Lin Ziyue , Chen Peng
Published: August 2024

Vitrimer-based composites combine the excellent performance of thermoset materials with the recyclability of thermoplastic materials. In this paper, based on ballistic impact experiments, the high-velocity impact resistance of CFRP before and after matrix modification and the failure mechanism of Vitrimer-based composites are investigated. The better impact resistance of Vitrimer-based composites is demonstrated in terms of ballistic limit, energy absorption, and failure modes. The failure mechanism of Vitrimer-based composites, which is different from that of conventional Epoxy-based composites, is found by CT scanning and verified in the strain signals.
Optimization design of the ducted fan powered high-lift system based on i-sight platform
Authors: Mao Sen , Li Gang , Zhao Chuangxin , Guo Qiang , Feng Wenliang , Xie Zongming
Published: August 2024

The vertical/short take-off and landing (V/STOL) unmanned aircraft vehicle (UAV) equipped with a ducted fan has a broad application prospect, and the design of the ducted fan-powered high-lift system has become one of the key factors in the design and development. The i-Sight platform is used to optimize the design of the 2D ducted fan-powered high-lift system in the paper. First, the parametric modeling of the main control parameters is carried out, and then the i-Sight platform is built to carry out optimization calculations. Finally, three optimal design points are found for detailed aerodynamic characteristics analysis, and then the optimal scheme is selected. The i-Sight platform is proven to be accurate and efficient. By moving the ducted fan horizontally forward from the initial position to 160 mm, a larger lift coefficient can be obtained, while moving the ducted fan vertically from the initial position to 300 mm, a larger lift resistance ratio can be obtained.
Effect of explosion venting effect on explosion response characteristics of box-shaped cabin
Authors: Ma Yinliang , Ji Chenli
Published: August 2024

In this paper, based on dynamics software ANSYS/LS-DYNA, a numerical model is established to simulate the dynamic response of a box-shaped cabin, and the validity of the numerical model is confirmed by comparing its results with existing literature or experimental data. Using the validated model, the study delves into dimensionless damage number of box-shaped cabin structures in relation to implosion responses, taking into account the explosion venting effect. Numerical analysis is performed to determine the relationship between dimensionless damage number Din
and deflection thickness ratio δ/H of the cabin’s plates. The study then considers the influence of the explosion venting effect on the implosion response of box-shaped cabins and proposes dimensionless damage number Din
‘
, which can predict structure damage of constraint explosion.
Ease-off modification and tooth contact analysis for near net shape face-gear
Authors: Han Yinan , Ding Miaojiang , He Shuaiqi , Yang Jianjun
Published: August 2024

An ease-off modification method for face gear by near-net shape forming was proposed to improve transmission performance. Firstly, based on the involute cylindrical gear surface, the completely conjugated tooth surface of the face gear was obtained, and the ease-off surface was constructed using second-order and fourth-order polynomials. Then, the tooth contact analysis for the modified flank is carried out. According to the loaded tooth contact analysis (TCA), the transmission error (TE) and contact path were consistent with the predesigned parameters. The noise experiments confirmed that the meshing performance of the ease-off modification tooth surface is better than that of the ordinary design method, which provides a reference for the topological modification design method for the die tooth surface of face-gear.
Numerical study on mechanical responses of AHR and BWD packer under a cyclic loading
Authors: Ma Xin , Shao Bing , Zhang Yongliang , Wang Xiaomei
Published: August 2024

For AHR and BWD packers which are commonly used in gas storage, the mechanical behavior and sealing properties are comparatively studied in this paper by the numerical simulations and experimental verification. First of all, through the experimental data fitting, the Yeoh equation is adopted for the constitutive relationship of the hyper-elastic rubber used in the packers. Based on the ABAQUS explicit FEM algorithm, the mechanical behaviors of the packer during the setting process and under working conditions with a cyclic loading are discussed and the stress risky spots of the sealing rubber are investigated. The results obtained in this work could be helpful for the engineering application of the packer in gas storage.
Simulation study on the dynamic response of X80 steel pipelines under explosive loads
Authors: Wang Yuntian , Yang Min , Hu Danping , Wei Qiujie , Zhang Ying , Guo Yuzhu
Published: August 2024

This research investigates the dynamic response and failure behavior of X80 steel pipelines under external contact explosion loads, a critical concern for oil and gas pipeline safety due to increased terrorist activities. The dynamic response characteristics are critically analyzed under ten different conditions of explosive charges, providing a detailed evaluation of the damage mechanisms, including denting and perforation. The study finds that wall thickness significantly influences the blast resistance of pipelines, with thicker walls offering better protection against explosive loads. This is substantiated by comparing destruction scenarios and morphologies of perforation holes between X80 and X70 steel pipelines. The paper concludes that increasing wall thickness markedly improves pipeline resilience against explosive destruction, contributing valuable guidelines for designing more robust and safer pipeline infrastructures.
Numerical simulation of impactor velocity under dynamic mesh-based double-sided pressurization
Authors: Zhou Jialiang , Tang Tong , Li Feiyin , Ma Shaojie , Shi Huifa , Liang Saisai , Zhang Yingzhong
Published: August 2024

In order to analyze the influence of different initial conditions on the performance of the impactor in a new impact testing device with double-sided pressurization, a two-dimensional numerical model of the impact testing device is established. Numerical calculations are performed on the model by using CFD software, combined with dynamic mesh technology. The influence of the initial pressure on the velocity performance of the impactor is obtained, and numerical validation is conducted with the existing impact testing device. The results show that the impactor under double-sided pressurization can achieve a higher velocity close to the experimental data, confirming the effectiveness and accuracy of this method. The research findings are helpful for predicting the velocity of impactors in impact testing devices under laboratory conditions.
Comparative Analysis of Performance Between Window and Eco-Cooler to Achieve Thermal Comfort in Hot Humid Climate
Authors: Pratiwi Niniek , Attaufiq Muhammad Muhdi
Published: August 2024

The increasing global temperatures have led to a higher demand for energy to maintain thermal comfort. In 2018, air conditioning was found to be the largest contributor to energy consumption, accounting for approximately 62% of the total energy used, according to data from the Ministry of Energy and Mineral Resources. Consequently, energy-saving initiatives that focus on cooling systems can play a crucial role in global energy conservation efforts. One such initiative is the implementation of Eco-Coolers. This study aims to compare the effectiveness of Eco-Coolers and windows in reducing room temperature for thermal comfort in hot and humid climates using Ansys simulations. The research adopts a quantitative approach by simulating the Eco-Cooler and window models using the Ansys application, followed by descriptive statistical analysis. The Eco-Cooler simulation involves a model with a diameter of D1 = 50 cm and D2 = 25 cm, which is then compared to a window measuring 45 cm × 100 cm. The results of the Eco-Cooler simulation demonstrate a decrease in temperature in all rooms where the Eco-Cooler is placed, with a maximum temperature of 27.05°C. This represents a decrease of 0.65°C from the initial temperature of 27.7°C. In contrast, the window model exhibits an upward airflow pattern, resulting in a maximum temperature of 27.35°C. This indicates a temperature drop of 0.35°C from the initial temperature of 27.7°C. Previous research on thermal comfort in Gorontalo City has shown that discomfort typically begins at a temperature of 29°C, with the peak of discomfort occurring at a temperature of 33°C. Therefore, based on the simulation results, the temperature range of 26.65°C – 27.05°C achieved by the Eco-Cooler can provide a comfortable or neutral sensation for individuals.
Native Architecture in Lampuuk Beach, Indonesia: A Challenge toward Sustainability in Coastal Resort
Authors: Rauzi E N , Sari L H
Published: August 2024

Native architecture plays an important role in designing a sustainable place. Old people learned from trial and error to accommodate the environment into their life. In this article, Lampuuk Beach is investigated in terms of the indigenous architecture conducted by the local people to get close to the sustainability concept. The beach is located in Aceh province which lies on the northern tip of Sumatra Island, Indonesia. It has been developed as a resilient coastal resort in Indonesia transforming from the radical traditional architecture of a recreation area into a modernist zoning-style layout. This phenomenon was generated by the Indian Ocean earthquake and tsunami in 2004. This research aims to identify the transition of coastal area changes in the last two decades and the challenges facing sustainability in Lampuuk Beach. The methodology is qualitative using a narrative architecture approach by illustrating the design characteristics of tourism facilities spreading along the coastal line, including cottages, restaurants, sitting areas, and the landscape overall. The data was collected from observations and interviews with local people. All data were elaborated on and interpreted to map the reform of the coastal tourism facilities. The result depicts the unfolding of the indigenous architecture of Lampuuk Beach transforming from recreational culinary areas into modern coastal tourism approaching sustainability, particularly in the resort sector. To conclude, the transition of native architecture in Lampuuk Beach demands coastal tourism facilities changes towards its sustainability.
Connectedness and Integration Analysis in Kampung Settlement: Using Space Syntax as Spatial Reconfiguration Model
Authors: Asriana N , Khidmat R P , Ujung V A , Satria W D , Hartono T , Nugraha M D , Santo A A , Putra M I E , Lubis T , Brilianto M Y
Published: August 2024

Informal settlements, commonly referred as kampungs, serve as integral components within the urban landscape of numerous cities. However, these settlements have significant vulnerabilities in relation to various urban difficulties, including but not limited to modernization, urbanisation, and other catastrophic circumstances. Nevertheless, there is a limited amount of study that specifically addresses spatial and physical concerns in the region of South Sumatra. This study seeks to examine the configuration and visibility of changes in Kampung Tuan Kentang, located in South Sumatera, Palembang, using the framework of space theory. The objective of this study is to restructure the spatial organisation of urban kampungs by means of enhancing connectedness and integration. The primary objective of this research is to address the physical and geographical challenges faced by Kampung Tuan Kentang, with the aim of enhancing the overall spatial quality and creating a more favourable environment. The current state of the structural network pattern in Kampung Tuan Kentang has characteristics of both a linear pattern and an organic spatial pattern, which are commonly observed in vernacular traditional settlements. The utilization of computational analysis is anticipated to function as a valuable resource for designers, urban designers, and urban planners in the evaluation of decision-making during the design phase. Additionally, it aids in identifying kampung areas that require future attention.
Typology of Perak Cultural Landscape: The Geographical Mapping Analysis
Authors: Hussain Nur Huzeima Mohd , Zakaria Ahmad Zamil , Abdullah Suzanah , Nayan Nadiyanti Mat
Published: August 2024

This study delves into the intricate typology of Perak’s cultural landscape through a comprehensive geographical mapping analysis. In Perak, the cultural landscape is experiencing changes, especially in the land and typology due to the overwhelming development. As cultural landscape plays a substantial role in historical and heritage values, efforts in documenting and analyzing the landscape change remain significant. This study documented a series of spatial data layers focusing on geographical context to describe and map the landscape typology in Perak. The geographical context including; agricultural landscape, coastal landscape, highland natural landscape, and lowland natural landscape was used as patches for the spatial and landscape-based metrics analysis. The analysis adopted the overlaying mapping technique by the Geographical Information System (GIS) in modifying and verifying the secondary data mapping by the Perak Structural Master Plan year 2040. The composite trajectory analysis in this study contributes to a more comprehensive cultural landscape typology toward sustaining cultural heritage value in the near future.
The Sustainable Lived Space of Pasar Baru Bandung
Authors: Darmayanti Tessa Eka , Bahauddin Azizi , Aryani Dewi Isma
Published: August 2024

This article is formed from the experiences of the authors when observations occurred at Pasar Baru in Bandung, Indonesia. The experience is the essential part of the Lived Space perspective by Henri Lefebvre, and that is the right approach to studying the sense of place of Pasar Baru Bandung. This strategy intends to provide a different view of the distinct values and spirit of Pasar Baru Bandung through the numerous everyday activities in and around it. Answering the research objectives was optimized with the interview, visual data, and exploratory literature. The concept of lived space also can lead to a sense of attachment in those who visit Pasar Baru Bandung. Recognizing a place contributes to its sustainability, and the sense of Pasar Baru is an identity that is no longer seen by its appearance but includes experiences. This article provides another understanding of lived space through the experience in Pasar Baru Bandung. This article also provides knowledge about Indonesian local values to a wider audience.