bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental study of adsorption characteristic of novel pyrazole-based metal-organic frameworks for volatile organic compounds
Authors: Ding Dong , Fang Lei , Qin Menghao
Published: December 2023

Volatile organic compounds (VOCs) are the major indoor air pollutants that affect human health, comfort, and working performance. Sorbent material and adsorption technology are considered to be one of the most effective and economical ways to remove VOCs from indoor air. Among many sorbent materials, metal-organic frameworks (MOFs) have received more and more attention because of their superior performance in capturing a variety of compounds. In this work, the adsorption characteristic of a newly synthesized pyrazole-based metal-organic framework (Al-pda) for different VOCs was investigated. First, the single-pass VOC adsorption rates of Al-pda and activated carbon were tested under different low-concentration VOCs mixture, which is in line with the practical application in the indoor environment. The results showed that Al-pda had an especially high adsorption ability for formaldehyde. The single-pass efficiency of formaldehyde adsorption was up to 89% at the beginning of the test and gradually stabilized at 66%. Compared with activated carbon, Al-pda had significantly higher selectivity and adsorption efficiency for the capture of formaldehyde. Then the effect of relative humidity on formaldehyde adsorption was investigated. After increasing the relative humidity from 15% to 65%, Al-pda’s formaldehyde single-pass adsorption rate almost remained at a similar level. Preliminary research showed that Al-pda is a promising material for the selective adsorption of indoor formaldehyde under humid conditions. More work is needed to probe this new MOF’s adsorption mechanism and application method.
The Influence of Application Rate of Hydrophobic Treatments on the Drying Behaviour of Brick
Authors: Cambray Toby , Marincioni Valentina , Altamirano Hector
Published: December 2023

ydrophobic (or water repellent) treatments have been proposed as a means to mitigate rain ingress and therefore moisture risks associated with internal wall insulation (IWI) on solid (and hence, usually historic) masonry walls. Some practitioners and researchers point out that such interventions may cause unintended consequences, in particular damage to the external masonry surfaces from freeze-thaw or cryptofloresence. Drying behaviour is important in both of these damage mechanisms. It is well established that hydrophobic treatments inhibit stage 1 drying. The depth of penetration also has a direct influence on the stage 2 drying, which is the focus of this work. Three types of treatment (silane-siloxane emulsion, silane only and siloxane only), with three different rates of application (resulting in varying depth of penetration and density of treatment) on a single type of brick, which were subjected to a drying experiment. This influence on stage 2 drying behaviour is explored.
Classification and simplified design rules concerning the moisture performance of capillary active insulation materials
Authors: Zirkelbach D , Tanaka E , Schöner T
Published: December 2023

Conventional interior insulation systems protect the wall from condensation in winter by the help of vapor barriers or vapor retarding insulation materials. However, these solutions also reduce the drying potential of the walls towards the inside. This can be a disadvantage if wetting from the outside due to rain or other influences takes place and the drying potential to the outside is not sufficient. In such cases, so called capillary active materials can be an alternative, because they provide additional drying potential to the inside in summer thanks to a rather low vapor diffusion resistance. In winter they work without vapor retarders because they can store and wick water away from the condensation plane back towards the interior by capillary action. In practice, there are currently many different materials under the label "capillary active" with a correspondingly wide range in terms of moisture storage, liquid transport and vapor diffusion resistance and it is difficult to decide, whether material is suitable for an application or not. There is still missing a common definition of the performance of such materials. While for most other materials already simplified design and application rules for the application as interior insulation are available, capillary active interior insulation materials still require an individual design, normally by the help of hygrothermal simulation. In order to simplify also their practice application, a classification of the moisture performance of capillary active interior insulation, considering the influencing parameters of relevance on the moisture level at the critical interface between wall and interior insulation was developed. On this basis, also a simplified verification process as well as design rules for the main practical application fields become possible, which allows designers to choose an appropriate system for the specific situation.
Performance of Bio-based Products for Interior Insulation of Solid Masonry Walls
Authors: Rode Carsten , Jensen Nickolaj Feldt , Møller Eva B. , Hansen Kurt Kielsgaard
Published: December 2023

A recent Danish project has studied the possibilities of using bio-based materials for interior insulation of solid brick walls, without the use of a vapour barrier. The purpose was to give indications of the possibility to use hygroscopic insulation material in positions as interior insulation, where it is known to be potentially vulnerable to moisture accumulation. Three bio-based thermal insulation materials were investigated: loose-fill cellulose insulation (two variants) and hemp fibre insulation commercially available in Denmark. The hygrothermal performance of the three insulation materials for internal retrofitting purposes was investigated in a large-scale experiment comprising several solid masonry walls. The test walls were built in an outdoor test field north of Copenhagen, and exposed to a controlled indoor climate. The experiments were conducted over 1 year and 9 months where moisture measurements were done in several locations within the walls, including the interface between insulation and masonry, as well as in embedded wooden components such as a beam end and a wall plate. The paper illustrates the results from experiments with or without a hydrophobizing treatment on the exterior surface as causes of moisture content in potentially critical places in the walls. Finally, some results from mould growth determinations are reported. Generally, high levels of moisture content were found in the interior insulation, particularly for non-hydrophobized walls, but critical mould growth conditions were found only in the case of one of the tested materials.
Hygrothermal performance of a CLT Ice Sports Arena in a Nordic climate
Authors: Skagseth Vegard A. , Andenæs Erlend , Aas Bjørn , Lobaccaro Gabriele , Kvande Tore
Published: December 2023

Indoor ice sports arenas are complex buildings that typically consume large amounts of energy. The energy is mainly used to freeze the ice rink and to keep the indoor air temperature and relative humidity at appropriate levels. Reducing the energy consumption and the carbon footprint from construction, operation, and material use, presents certain challenges from a building physics point of view. These challenges are especially prominent if the ice sports arena is operated in a climate featuring summer seasons that are warmer than the indoor air temperature and winter seasons that are colder. This study investigates the hygrothermal performance of an ice sports arena built using cross-laminated timber (CLT), located in Sandefjord, Norway. Hygrothermal simulations of the exterior wall were conducted and analysed using WUFI. Locally retrieved weather data is compared to WUFI simulations done in the design process, which were based on Moisture Design Reference Year (MDRY) files for Oslo. The moisture performance of the wall as built is investigated for three different indoor temperatures. Modifications to the wall to improve moisture performance are also investigated. Results indicate that the MDRY files do not accurately reflect the climate on site. The performance of the wall assembly is found to depend greatly on indoor temperature. For indoor temperatures colder than 12 °C, substantial condensation and moisture problems are predicted during summer. None of the investigated modifications are found to sufficiently increase the moisture performance of the wall. Drastic measures may be required to improve moisture safety.
Hygrothermal properties of hollow brick masonry used in veneer
Authors: Karjala P , Tuurala I , Tuominen E , Valovirta I , Vinha J
Published: December 2023

The material properties of a brick masonry are important when modelling or comparing different veneers. The effect of mortar joint, however, is somewhat an unknown variable. In this study, two different firing batches of a hollow burnt-clay brick product were tested for thermal conductivity, water vapor permeability, water absorption coefficient and capillary moisture content. Brick and mortar materials were tested both exclusively and as masonry specimens. The effect of brick-mortar interface was within margin of error for the first brick batch with slightly lower density, while batch two water vapor permeability, water absorption coefficient and capillary moisture content were noticeably affected. The effect of brick-mortar interface seems to be dependent on brick properties. The differences in hygric properties between brick batches were large, but below 100 %. Accounting for mortar using area weighted properties can improve modelling accuracy, but other factors such as workmanship, degradation and brick batch differences are likely more important.
Determining the net present global warming potential of energy saving measures in buildings
Authors: Petersen Arnkell Jonas , Thiis Thomas Kringlebotn
Published: December 2023

A framework for evaluating the net present global warming potential (GWP) of an energy saving measure is presented, based on an already established LCA methodology. The framework establishes a connection between the emissions from materials, energy, and the expected time horizon of the impact on energy use. The framework is designed to be used as a decision-support tool by practitioners to evaluate the GWPNP impact of a design decision. This has broad relevance as decisions on building standards are often based upon a cost-efficiency approach, e.g. The European Energy performance of buildings directive (EPDB) requirement that building codes be based upon a cost-efficiency approach. And as the requirements are driven by cost there is no inherent balance between the GWP of the energy saved, and the GWP-investment in the measures that impact energy use. The proposed methodology is exemplified by applying it to investigate the optimum insulation thickness for typical wall construction for different locations/climates and time of installation in Norway and comparing these with current industry standards.
Exploring the health and energy savings dilemma in swimming facilities and the potential influence of Positive Energy Districts
Authors: Mattsson Moa , Olofsson Thomas , Nair Gireesh
Published: December 2023

Positive energy districts (PED) are neighborhoods with a net positive energy balance with the main goal to create sustainable districts that contribute to the energy transition. The three pillars energy efficiency, renewable energy, and energy flexibility forms the foundation of PEDs, and ‘Quality of life’ is one of the key principles.

Indoor swimming facilities for recreation and sports, also called aquatic centers or swimming halls, are important for healthy lifestyles. They are highly energy-demanding facilities due to the large volumes and strict heating- and ventilation requirements to ensure the health of staff, visitors, and bathers. The large energy consumption indicates good potential to reduce their energy use. One possibility might be to include aquatic centers in PEDs: the district could support the facility with locally produced renewable energy. There are also studies that investigates innovative solutions regarding aquatic centers that might have potential to increase resilience and flexibility in the district.

However, one important aspect in studies on energy use in aquatic centers that is often neglected is the presence of disinfection by-products (DBP), which are found in the air and water of chlorinated swimming pools. Several DBPs can lead to health issues, such as asthma, eye irritation, and even cancer.

There are often conflicting goals in studies on swimming halls. The connection between DBP and energy is currently missing, and it could lead to projects compromising health over energy savings. Based on a literature review, this study highlights the research gap between DBPs and energy use in swimming facilities. A suggestion is also presented to integrate swimming halls into PEDs with the aim of increasing possibilities for a healthy lifestyle, supporting the aquatic center’s energy demand with renewable energy, and exploring new solutions for flexibility and resilience in the district.
A Critical Review of Lighting Design and Asset Management Strategies. Illuminating Practices and Lessons Learned for Swedish Public Libraries
Authors: Shen Jingchun , Zhang Xingxing , Mylly Nina , Lin Jing
Published: December 2023

Most lighting is only designed to meet the visual needs in most public library environments in Sweden. Although lighting-related impacts are relevant to six Unite Nations sustainability goals, some important lighting considerations, such as circadian phase disruption, mode and productivity impact, and energy-efficient operation, are missing in current lighting operating practices. Moreover, most of the current lighting asset management practice in public buildings remains “fix it if only it breaks”. With respect to people-centric health factors, visual index, and lighting asset energy-efficient operation, this study sublimates lighting into a new perspective. Finally, the suggested comprehensive lighting operating strategies integrating digital twins can help designers and operators in defining the optimal design/control strategy in public-built environments, like public library. Digital twin-based decision-making is expected to be applied to lighting design and control in public spaces that improves visual acuity and comfort, positively impact mood and productivity, and provides recommendations on engagement principles under Environment Social Governance (ESG) framework to asset manager/operators.
Sampled Value Optimization Based Bearing-only Localization
Authors: Huang Yushuang , Xu Ziqi , Tang Xiafei , Zou Yiqun
Published: December 2023

This paper proposes a sampled value optimization based estimator (SVOE) for bearing-only target localization (BTL). When the variances of the bearing noise are unknown, multiple measurements are made at the same sensor location. Then the sampled moments are calculated and used to establish a cost function. When the cost is minimized, the optimal is proven to be consistent and has the covariance proportional to the Cramer-Rao lower bound. The simulation results demonstrate the superior performance of the SVOE method over other methods.
A Method for Identifying Energy Consumption of Machine Tools Based on Integrated Models
Authors: Xie Yang , Dai Yiqun , Gao Shangshang , Liu Jinfeng
Published: December 2023

The uncertainty of the dynamic change process of expenditure of energy from machine tools seriously hinders the development of an intelligent and green manufacturing industry. In response to the multifaceted impact of identification methods in the process of energy consumption change, the difficulty of extracting high-quality features, and the complexity and nonlinearity of energy consumption curves, an identification method for predicting the energy consumption of machine tools based on integrated models was proposed. Taking CNC milling as an example, the model of energy consumption based on different cutting periods was established, which was then trained and predicted by using the preprocessing signal based on Random forest (RF). Meanwhile, the RF was used to identify the cutting stages and realize the energy consumption classification prediction. The advantage and availability of this method have been demonstrated through practical cases, and it has been verified that this recognition method can accurately predict different operating states and energy consumption of each stage on machine tools.
Enabling intelligent HVSR loose fault diagnosis based on vibration perception
Authors: Zhao Changwei , Huang Weiming , Qian Yucheng , Yang Haitao , Liu Zhongyong , Mao Lei , Li Shaofei
Published: December 2023

The significance of high-voltage shunt reactors (HVSRs) in ensuring the reliability of power grids is widely acknowledged. Nevertheless, the persistent mechanical vibrations experienced by HVSR can loosen vital components such as windings, iron cores, and bolt fasteners. If the mechanical loose fault cannot be detected and mitigated timely, the vibration will be further aggravated, which tends to cause additional detects such as overheating and discharge, even fire disasters. Therefore, it is essential to diagnose loose faults in high-voltage shunt reactors. This study presents a unique data-driven method that utilizes optimal vibration test location selection and a densely connected neural network (DenseNet) for diagnosing loose faults in shunt reactors. Firstly, we integrate the least square method and R-square to explore the fault sensitivity of the vibration signal collected in different locations on the external tank surface, based on which the optimal vibration test points can be determined. Then the vibration data acquired in the selected points are input into the DenseNet model to achieve high-precise loose fault detection and diagnosis for high-voltage shunt reactor. Furthermore, with test data collected from a 35 kV high-voltage shunt reactor, the diagnostic performance of the proposed method is verified and highlighted.
Research on the Application of Motor Field-Oriented Control in Vehicles
Authors: Jing Junchao , Yang Tianyu , Ma Qiaoli , Liu Yiqiang , Su Yangyang , Dai Zhengxing
Published: December 2023

The motor application of the FOC strategy of the hybrid system in this text is the battery heat control. The specific contents are as below: SVPWM control. SVPWM is based on the three-phase symmetrical sine wave voltage supply and three-phase symmetrical motor stator ideal flux circle as a reference standard, with different switching modes of three-phase inverter for appropriate switching, to form PWM wave and to form the actual flux vector to track its accurate flux circle. By applying reactive voltage with high-frequency variation and using the FOC control strategy, the inductance characteristic of the motor winding is constantly utilized to generate alternating current on the bus. By taking advantage of the high internal resistance of the cell at low temperatures, the joule heat is constantly generated on the cell. While avoiding the risk of lithium analysis of the cell, heat is generated from the cell itself, and the temperature of the cell is raised. The vehicle results are conducted and show that the battery heat performance is enhanced.
Research on the Physical Reproduction Method of Single-phase Grounding Fault in 10 kV Distribution Network Based on Digital Mirroring
Authors: Yin Hui , Zheng Ge , Wang Shizhe , Chen Peng , Wu Yan , Gao Wenpeng
Published: December 2023

It is necessary to construct a physical reproduction environment that conforms to the actual working conditions of single-phase grounding faults in 10 kV distribution networks, to effectively verify the single-phase grounding fault disposal capability of distribution automation equipment. In this article, a physical reproduction method of a single-phase ground fault in distribution networks based on digital mirroring is proposed. A digitized mirror model of a single-phase ground fault of a 10 kV distribution network is constructed. The system architecture for equivalent physical reproduction of single-phase grounding fault characterization is designed. Then the solutions to the critical technical problems in the realization are proposed. The reproduced single-phase ground fault signal was applied in the functional verification work of the first and second fusion distribution equipment. The experimental results show that the single-phase grounding fault in the 10 kV distribution network reproduced by this method comprehensively verifies the correct rate of the equipment for the single-phase ground fault disposal as well as the ability to prevent false action. Moreover, the reasons for the failure of the equipment s single-phase grounding fault disposal function were discovered.
Judgment Logic of 10 kV Line Trunk Power Failure Based on Association Rules
Authors: Wei Wenting , Chai Yufeng , Cai Bing
Published: December 2023

Aiming at the traditional 10 kV line trunk outage fault judgment logic which mainly adopts the fixed receiver to collect the emergency repair work instructions and is susceptible to the influence of restrictive logic transmission, resulting in the problem of low fault judgment feedback integrity, it is necessary to design a new association rule-based 10 kV line trunk fault judgment logic. The association rules are used to generate the trunk fault judgment strategy, clarify different fault judgment attributes, and calculate the importance of the association rules by the improved Apriori algorithm. Combined with the spatial information service and the basic application service, the information interaction is realized through the bus exchange to generate the optimization logic of the 10 kV trunk fault judgment and complete the trunk fault judgment. The results of the example analysis show that the designed trunk line outage judgment logic has high feedback integrity, which proves that the designed outage judgment logic is effective and reliable with a certain application value, and makes a certain contribution to reducing the risk of trunk line outage.
Offshore Wind Power Transmission Decision-making Based on Grey Correlation and Topsis
Authors: Li Zhichuan , Qi Lei , Sun Zhaoheng , Chen Shi , Liu Xiaoyan , Xiao Shi , Wang Yong , Chen Juan
Published: December 2023

With the profound transformation of the global energy structure, the development and utilization of wind energy have become the focus of global attention. The offshore wind power industry has ushered in a historic development opportunity and China’s offshore wind power industry has entered the fast track of development. However, due to the variety of transmission schemes available for offshore wind power, there are many differences in the economy, reliability, environment, risk, and other aspects of different transmission schemes, so it is difficult to make the optimal decision. To comprehensively compare the advantages and disadvantages of different transmission schemes in actual scenarios, this paper first identifies their influencing factors to obtain an evaluation index system and uses the entropy weight method to determine the index weight based on the index evaluation data of typical offshore wind power transmission projects at home and abroad, and the grey correlation method and TOPSIS method are integrated to build a comprehensive evaluation model suitable for offshore power transmission. Finally, the scientific and rigorous nature of the research method and model is verified by example analysis. The optimal decision comprehensive evaluation model constructed in this paper can realize scientific and comprehensive evaluation of offshore wind power transmission schemes and has important decision-making significance for the selection of transmission schemes in different scenarios.
An Exquisite Modeling Method for Energy Storage of MMC
Authors: Yang Xiaodong , Jiang Wenjin , Huang Xianan , Tu Xiazhe , Yang Yanwei , Shen Yu , Liu Qiaomei , Que Dingfei , Zheng Wendi , Liu Zhiyuan
Published: December 2023

At present, battery energy storage systems are available in increasingly higher voltage levels and capacities. The traditional topology cannot meet the demand, and the converter needs to adopt the multilevel voltage topology. In this paper, an exquisite equivalent modeling method for energy storage modular multilevel converter (MMC) is proposed. In this method, the model parameters of the bridge arm and battery pack are obtained by the Kalman filtering algorithm and improved recursive least square method. Secondly, the whole bridge arm is equivalent by using Thevenin’s theorem, and the simplified equivalent modeling of the whole bridge arm is realized. Time domain simulation results show that this method can achieve fine equivalent modeling of energy-storage MMC, reduce the number of electrical nodes in the simulation circuit, and greatly reduce the amount of calculation.
Comparison of tensile strain capacity models of oil and gas pipelines
Authors: Zhang Zhenyong , Liu Yuqing , Deng Liang , Zhang Dong , Fu Yaru , Wang Hao
Published: December 2023

In the field of strain-based pipeline design, the widely used pipeline tensile strain capacity models mainly include CSA Z662, PRCI-CRES, and EXXON MOBIL. In this paper, the methods for calculating the ultimate tensile strain, toughness, and other key parameters of various models are emphatically introduced, and their applicable ranges are compared. Ninety-six sets of full-scale test and curved wide plate test data are collected in this paper. The prediction accuracy of various tensile strain capacity models under different steel grades is compared and verified by the test results. The CSA Z662 model has few parameters to consider, the TSC prediction value is relatively low, and EXXON MOBIL has more nonconservative situations when the strain is less than 4%. The PRCI-CRES model has the highest prediction accuracy.
Microporous Polyurethane Elastomer’s Comprehensive Properties Affected by Flame Retardant EG/APP
Authors: Wu Xiaoxia , Zhang Xudong , Wu Jingpeng , Li Xiaodong , Su Xing , Zhao Zhiying , Jiang Hao , Zou Meishuai
Published: December 2023

The mechanical characteristics, creep resistance, fatigue resistance, and other comprehensive properties of flame retardants/microporous polyurethane elastomers (FRs/MPUE) have not been systematically researched. Because of this, we used expandable graphite (EG) and ammonium polyphosphate (APP) to conduct this study on FRs/MPUE composites. The thermal degradation and flame retardant characteristics, tensile strength, compressive creep, and dynamic and static stiffness ratio of FRs/MPUE were studied. The findings demonstrated that the optimum synergistic flame retardant effect occurred when the ratio of EG to APP was 2:1. The LOI of MPUE reached 30.5%. The vertical combustion grade achieved V-0. The stage of thermal decomposition was the most stable. However, compared with pure MPUE, the tensile strength was slightly decreased, and the compressive creep and dynamic and static stiffness ratio were slightly increased. The MPUE’s LOI value was more than or equal to 26% when the EG to APP ratio was 2:1 to 1:2. The tensile strength was basically the same as that of pure MPUE. The compression creep was less than 5%, which met the B1 flame retardant requirements and creep resistance performance indicators of floating floor vibration-damping pads.
The influence of impinging distance variable on the effect of submerged jet scour
Authors: Chen Hao , Tang Yang , Li Jinyuan , Zhu Faxin , Teng Xianbin
Published: December 2023

In this paper, the effect of jet holes under different impinging distances was studied by using Flow-3D fluid software. The results show that when the impinging distance of the jet is small, the profile is random. There is a critical impinging distance. At this time, the width and depth of the hole enter a relatively static state, which can be regarded as the key point of the transition stage. After exceeding the critical impinging distance, the depth and width of the hole quickly reach the maximum value; as the impinging distance continues to increase, the hole parameters gradually decrease. The empirical formula of hole parameters changing with impinging distance under specific working conditions is obtained.
Investigation of mechanical responses of underground fortifications at different explosion distances
Authors: Lin Qindong , Feng Chun , Zhang Yulei , Gan Yundan , Yuan Jianfei , Jiao Wenjun
Published: December 2023

The mechanical responses of underground fortifications subjected to blast loading is an important topic related to survival and security ability. Based on a FEM-DEM coupled algorithm, the difference in mechanical responses of underground fortifications subjected to different blast loadings is studied. Firstly, full-time numerical simulations of underground fortifications are conducted. Then, the mechanical characteristics (i.e., displacement and crack) of underground fortifications are analyzed quantitatively. The result indicates that the maximum displacement of underground fortifications gradually reduces from 3.35 m to 1.90 m when the horizontal distance D
H increases, and the rock volume V
C and V
F gradually decrease with the increase of D
H. The crack ratio at the same moment gradually decreases with the increase of D
H, and the spatial distribution of fracture type changes significantly with the increase of D
H.
Fluid-structure Interaction Study on Drag Characteristics of Flexible Ribbon
Authors: Tan Hanlin , Ruan Wenjun
Published: December 2023

The flexible ribbon can be used as a projectile stabilizing device to provide a stable moment for the projectile, and the research on its drag characteristics is of great significance. This paper uses the arbitrary Lagrange-Euler (ALE) method to simulate the fluid-structure interaction process of the ribbon swinging in the airflow. The numerical method is validated by comparing it with wind tunnel experimental results from previous literature. This study utilized numerical simulation to investigate the impact of inflow velocity, ribbon material properties, and ribbon shape on drag characteristics. The research concluded that for a single ribbon, the drag value increases as the incoming flow velocity, ribbon material density, elastic modulus, and length-width ratio increase. In addition, the drag value of the annular ribbon is greater than that of the double ribbon. The drag values of the double ribbon and the annular ribbon are averaged to one side, the unilateral drag of the annular ribbon is greater than that of the single ribbon, and the unilateral drag of the double ribbon is smaller than that of the single ribbon. The conclusions can provide a reference for studying flexible ribbon stabilized projectiles.
Stress and Couple Stress Concentration and Plastic Rotation Analysis of Local Micro-structure of Flat Plate
Authors: Yan Weilin , Liu Zhanfang
Published: December 2023

In classical elasticity, the analytical solution of the stress concentration coefficient at the edge of a circular plate hole is 3, but the experimental result is less than 3, and the fatigue theory still has no theoretical answer to the mechanism of fatigue. For the problem that the stress concentration coefficient is less than 3, the stress and couple stress concentration at the hole edge of a circular plate hole is calculated using generalized elasticity. On this basis, the strain-elastic and rotation-plastic theory is put forward, and an example of a flat wedge structure is used to demonstrate the plastic curvature of the contact boundary of different materials to explain the mechanism of fatigue. Through calculation, it is found that there is a stress concentration at the edge of the hole and a couple of stress concentrations, and the stress concentration coefficient decreases with the decrease of the hole diameter. For flat wedge structures, the plastic curvature is mainly concentrated on the contact surface of different materials, and the plastic curvature will increase obviously when the boundary changes. This paper provides a new idea for the development of fatigue theory.
New Wind and Pressure-resistant Structural Design and Static Simulation Analysis of Continuous Greenhouse
Authors: Chen Shuheng , Wang Yongjiang , Tang Shiyi , Zhao Yinglei , Xu Baoyu , Zhang Chenghao
Published: December 2023

To improve the wind and snow resistance of the continuous round-arch greenhouse skeleton structures, a new wind and pressure-resistant continuous greenhouse with arch spars and diagonal ties is designed in this study. By increasing the number of secondary arches, arch spars, and diagonal ties, and optimizing the traditional spars, this skeleton structure not only improves the snow pressure resistance of arch bars but also enhances the resistance to wind loads. Taking wind load and snow load in the Hangzhou area of Zhejiang province as an example, ANSYS workbench software was used to analyze and calculate the stress and displacement of this shed, and it was found that the maximum stress value could reach 88.641 MPa and the maximum bit amount was 10.316 mm. Compared with the traditional plastic continuous shed, the optimized structure of wind and pressure-resistant continuous shed can effectively reduce the arch displacement and enhance the stability of the structure.
A Class of Parameter Interpolation Iteration Algorithm based on Clem- Equations
Authors: Guo Qiao , Yang Bing
Published: December 2023

The Newdon Iterative method and its deformation mostly require calculating the derivative of nonlinear equations. In practice, many functions are complex, and there are limitations in finding high-order derivatives. This paper fits an existing iterative format by establishing n times interpolated polynomials, n conditions are used to construct a system of linear equations with n equations and n + 1 unknowns, in which the previous n unknowns can be expressed by the n + 1 th unknown by Clem’s rule, to achieve the purpose of reducing the number of derivative calculations. Convergence analysis and numerical examples verify that the algorithm is better than Newdon iteration, and can be better used in path trajectory optimization and fractional time delay control.
Stability Analysis for Vehicular Platooning Subjects to Disturbances
Authors: Lei Hongbo , Zeng Ye , Zhang Min
Published: December 2023

In our work, a control problem of vehicular communications platooning, subject to disturbances, is researched. To eliminate the spacing errors of the platooning, a novel effective non-singular terminal sliding-mode control (TSMC) law is designed for the following vehicles, where the problem of singularity is addressed. Furthermore, a coupled sliding-mode surface is presented for vehicular platooning. Then, based on Lyapunov stability theory, the spacing errors for the platooning can be forced into the designed TSMC surface in finite time and finally reach zero. The string stability of the platooning is also proven via a series of Laplace transforms. Finally, the validity of the proposed law in dealing with disturbances is expressed in simulation results.
Modeling and Analysis of a Large Stroke Tristable Vibratory Energy Harvester
Authors: Huang Haijie , Fan Yanhong , Wang Ze
Published: December 2023

In order to magnify the responding frequency band of the energy collector under lower excitation, this paper constructs a tristable structure using four inclined springs, achieving a larger stroke. On this basis, a tristable electromagnetic energy harvester is proposed. The dynamic formula is solved by the numerical integration method, and the dynamic characteristics and current output characteristics of the system are analyzed. At the same time, for output power, the ratio of stiffness coefficients of the system spring was researched. It was found when the ratio of stiffness coefficients of the spring was 2/3, it would cause the potential energy function curve to be asymmetric. Compared to a symmetric system with a ratio fixed 1 of stiffness coefficients of the spring, the average output power increased by about one tenth. The research results indicate the proposed tristable energy collector can achieve energy collection under low amplitude and low-frequency excitation.
Power Insulator Defect Detection Based on Multi-scale Dense Adaptive Sensing
Authors: Yuan Hanwen , Wang Jingang
Published: December 2023

To solve the problem that the insulator image taken by an unmanned aerial vehicle (UAV) in the process of power inspection cannot be accurately identified, located, and detected, a power insulator defect detection method based on multi-scale dense adaptive sensing is proposed. Firstly, a dense connection architecture based on multi-scale is proposed to improve the feature extraction ability of the algorithm for insulators. Secondly, an adaptive multi-scale weight transfer module is proposed to improve further the perception ability of the algorithm for insulator defect features and input multi-branch feature images. Finally, a multi-branch detection unit is proposed, and the parallel attention structure is used to improve the detection effect of the network on different scale branch insulator images. The experimental results in the existing insulator defect data set show that the proposed network can accurately identify and locate insulator defects, with an average detection accuracy of 95.6%, superior to the comparison algorithm in accuracy and speed.
Power-Impact-Harmonic Characteristics Analysis and Modeling of Diversified Power Loads in Urban Power Grid
Authors: He Mingfeng , Wang Ke , Kong Wei , Ying Yingjun , Chi Yuan , Meng Qinghao
Published: December 2023

Different load models of the same load have different effects on power flow calculation, short circuit calculation, voltage stability, and frequency stability after power system accidents. In this paper, some power load components in urban power grids are modeled by analyzing and fitting the measured power curve of load components, and they are divided into the power model, impact model, and harmonic model according to their characteristics. The power model includes the power models of some household appliances, industrial motors, and arc furnaces. The impact model includes the time series fitting model and probability fitting model. According to the measured power curve of load components, the load model established in this paper can avoid some risks of power calculation caused by the absence of a detailed load model.
Day-ahead economic dispatch of building energy system considering virtual energy storage
Authors: Ren Chunlei , Zhu Xuyang , Qu Yuqian
Published: December 2023

For the increasing proportion of building energy consumption in global energy consumption in recent years, this paper proposes a day-ahead economic dispatching method of building energy systems considering virtual energy storage. Firstly, virtual energy storage is modeled according to the thermal inertia of the building. Then, a building energy system model with a distribution grid, photovoltaic generator sets, and heating equipment (heat pump) is constructed. Finally, a day-ahead economic optimal dispatch of the building energy system considering virtual energy storage is modeled to achieve the charging and discharging management of virtual energy storage. Case study results show that under the precondition for meeting the thermal comfort of the occupants, the daily electric power purchase of the building energy system after considering virtual energy storage is reduced by 278.69 kW. The daily comprehensive operating cost is decreased by 8.3%. The validity and reliability of this suggested approach in this paper are proved.
Two-stage Robust Optimization Scheduling Considering Wind Uncertainty and Multi-area Frequency Dynamic Safety
Authors: Zhang Dan , Xin Xiangyu , Wang Tao
Published: December 2023

The large-scale wind power grid connection exacerbates the problem of uneven distribution of inertia between different regions, posing challenges to the frequency security defense of multi-area systems. This article proposes a two-stage robust optimization scheduling model that considers both the uncertainty of wind power output and the dynamic safety of multi-area frequencies. Firstly, according to the conditional value at risk theory, the operating cost and operating risk of the multi-region system are optimized, and the acceptable safety boundary of wind power is obtained. Secondly, multi-zone frequency dynamic safety verification is carried out in harsh wind power scenarios. Decouple the reserve capacity into non-accident reserve and accident reserve, and nest them separately in a two-stage model to achieve clear solution ideas. Finally, the two-stage optimization problem is solved through the column and constraint generation algorithm. The simulation results of numerical examples show that the model and method can effectively improve the frequency response capability of the multi-region system, so as to ensure the safe and economical operation of the system.
Failure mode analysis and severity measurement method for hydropower equipment
Authors: Zhang Chunhui , Chen Jieyu , Xu Ge , Jiang Shixin , Yi Wanshuang
Published: December 2023

To meet the practical needs of effective failure management and safe operation of hydropower systems, the classification and description standardization of the failure modes are studied based on the statistical analysis of historical maintenance data of in-service hydropower equipment. The method of building the failure mode library is then offered, followed by the specification of failure mode codes. Given the characteristics of the hydropower equipment, a severity rating method and the severity measurement model of failure modes for hydropower equipment are proposed, with definition criteria built using fuzzy semantic techniques. Finally, a thrust bearing system of the hydraulic generator sets is used as an example to validate the method of failure mode analysis and severity measurement, and practical suggestions for implementation of severity measurement are given in this paper.
A high dynamic carrier acquisition and tracking algorithm for space coherent optical communication
Authors: Wang Dizhu , Zuo Jinzhong , Jin Yi , Yang Li , Xu Changzhi
Published: December 2023

In coherent optical communication, the Doppler frequency offset reaches several GHz, which seriously affects the performance of the coherent demodulation system and increases the bit error rate. In this paper, a novel carrier acquisition and tracking algorithm for spatial coherent optical communication is proposed. The algorithm adopts the dual-locked frequency loop that the CPAFC tracking algorithm is effectively combined with the ODAFC tracking algorithm. The CPAFC tracking algorithm can be used for frequency offset gradually change capture and tracking, and the ODAFC tracking algorithm can capture large frequency offset, and according to the locked state control the working state of the two FLL loops. In the condition of stable locked, use only the CPAFC tracking algorithm to capture the gradually changing frequency offset; in the other condition, use two FLL loops together. The experimental results show that the 5Gbps BPSK laser communication performance loss is less than 1.5 dB when the Doppler frequency offset is 2.5 GHz, and the carrier frequency offset change rate is 20 MHz/s.
Object Detection in Aerial Remote Sensing Images with Multi-scale Feature Enhancement
Authors: Zhang Kunpeng , Zhao Ruiqi
Published: December 2023

In target detection of satellite images, the significant differences in target scales can lead to many missed detections and false detections. To address this issue, an object detection algorithm based on improved YOLOv5s is proposed in this paper. Firstly, multiple dilated convolutions with different sampling rates are introduced in the Backbone network to aggrandize the capacity to extract detailed features of targets of different scales. Secondly, an adaptive feature fusion module is introduced based on the feature pyramid structure to fully utilize the characteristic information of different scales, and increase the detection capability of the network. Finally, experiments are carried out on the DIOR data set, and the proposed algorithm is demonstrated to be effective. Compared with traditional YOLOv5s, the proposed algorithm reduces missed detections and false detections and improves the overall accuracy of mAP (mean Average Precision) by 2.8%.
Real-time Sequence Images Registration based on Fast Least Squares Feature Point Tracking
Authors: Hu Yiqun , Chi Longyun , Liu Xuesong , Dong Jing
Published: December 2023

This study addresses the issues of diminished precision and sluggish computational pace observed in current sequence image registration algorithms. A sequence image registration algorithm based on adaptive feature point selection (AFPS) and fast least squares tracking (FLST) is proposed. The corner points are detected by the FAST algorithm. The feature points are selected according to the distribution and intensity of the corner points. The fast least squares tracking technique is employed to compute the displacement of feature points between successive images. The proposed feature point selecting approach and the tracking method substantially increased the efficiency and performance of the registration algorithm. The registration algorithm is evaluated by sequence images taken by drones. The test outcomes demonstrate that, in comparison to existing algorithms, the proposed algorithm significantly enhances both the accuracy and real-time capabilities of sequence image registration.
Naive Bayesian classifier target recognition based on ridge features
Authors: Shi Yuhong , Yue Lei
Published: December 2023

Traditional time-frequency algorithms do not have a high feature recognition rate for targets in a low signal-to-noise background, and the number of operations for classification using plain Bayes is large and slow. To solve the above problems and achieve recognition of different ship echo signals in water, this paper proposes a target recognition method based on time-frequency ridge features by using collected audio data of different ship types, combined with Fourier Simultaneous Compression Transform (abbreviation: FSST), starting from time-frequency features, by extracting the FSST time-frequency ridge and finally using the Hopper Parsimonious Bayes classifier to obtain respectively. The recognition rate of ships under FSST and the recognition rate of ships based on ridge line features are obtained respectively. The final comparison shows that the correct recognition rate of the plain Bayesian classifier using the spine features of the time-frequency map is much higher than that of the conventional FSST time-frequency method, and it also outperforms the FSST in terms of computational power and speed.
Research on Key Technologies of High-Reliability Telemetry Transmitters for Launch Vehicle Carrying
Authors: Zhu Jing , Yan Shuai , Huang Hongjia , Cong Wei , Gong Changhui , Zheng Fanfan , Li Shuo
Published: December 2023

To solve the problem of single-point series components in the internal circuit of the current PCM/FM launch vehicle carrying telemetry transmitter, this paper proposes a new circuit architecture that can eliminate most of the single-point working components of the transmitter without changing the external interface and usage mode, thus improving the reliability of the whole system. This scheme uses large-scale integrated circuits to reduce the number of chips in the transmitter. Two improvements are made in the overall structure of the transmitter. One is to use a zero intermediate frequency (IF) orthogonal up-conversion scheme to replace the traditional high IF superheterodyne scheme, which reduces the number of single-point series components in the circuit. Another is to utilize redundancy design, increasing backup and fault detection channels. According to the development of domestic devices, this paper uses two domestic B9361 radio frequency (RF) conversion chips to realize two ways up-conversion as main and backup channels and two ways down-conversions as fault detection channels. The experimental results show that the new telemetry transmitter based on this scheme can be compatible with the current transmitter and effectively improve the reliability of the whole system.