Application and optimization design of non-obstructive particle damping-phononic crystal vibration isolator in viaduct structure-borne noise reduction

The problems associated with vibrations of viaducts and low-frequency structural noise radiation caused by train excitation continue to increase in importance.A new floating-slab track vibration isolator-non-obstructive particle damping-phononic crystal vibration isolator is proposed herein,which uses the particle damping vibration absorption technology and bandgap vibration control theory.The vibration reduction performance of the NOPD-PCVI was analyzed from the perspective of vibration control.The paper explores the structure-borne noise reduction performance of the NOPD-PCVIs installed on different bridge structures under varying service conditions encountered in practical engineering applications.The load transferred to the bridge is obtained from a coupled train-FST-bridge analytical model considering the different structural parameters of bridges.The vibration responses are obtained using the finite element method,while the structural noise radiation is simulated using the frequency-domain boundary element method.Using the particle swarm optimization algorithm,the parameters of the NOPD-PCVI are optimized so that its frequency bandgap matches the dominant bridge structural noise frequency range.The noise reduction performance of the NOPD-PCVIs is compared to the steel-spring isolation under different service conditions.

A Deep Learning Approach to Shape Optimization Problems for Flexoelectric Materials Using the Isogeometric Finite Element Method

A new approach for flexoelectricmaterial shape optimization is proposed in this study.In this work,a proxymodel based on artificial neural network(ANN)is used to solve the parameter optimization and shape optimization problems.To improve the fitting ability of the neural network,we use the idea of pre-training to determine the structure of the neural network and combine different optimizers for training.The isogeometric analysis-finite element method(IGA-FEM)is used to discretize the flexural theoretical formulas and obtain samples,which helps ANN to build a proxy model from the model shape to the target value.The effectiveness of the proposed method is verified through two numerical examples of parameter optimization and one numerical example of shape optimization.

A Hybrid Parallel Strategy for Isogeometric Topology Optimization via CPU/GPU Heterogeneous Computing

This paper aims to solve large-scale and complex isogeometric topology optimization problems that consumesignificant computational resources. A novel isogeometric topology optimization method with a hybrid parallelstrategy of CPU/GPU is proposed, while the hybrid parallel strategies for stiffness matrix assembly, equationsolving, sensitivity analysis, and design variable update are discussed in detail. To ensure the high efficiency ofCPU/GPU computing, a workload balancing strategy is presented for optimally distributing the workload betweenCPU and GPU. To illustrate the advantages of the proposedmethod, three benchmark examples are tested to verifythe hybrid parallel strategy in this paper. The results show that the efficiency of the hybrid method is faster thanserial CPU and parallel GPU, while the speedups can be up to two orders of magnitude.

Full-Scale Isogeometric Topology Optimization of Cellular Structures Based on Kirchhoff-Love Shells

Cellular thin-shell structures are widely applied in ultralightweight designs due to their high bearing capacity and strength-to-weight ratio.In this paper,a full-scale isogeometric topology optimization(ITO)method based on Kirchhoff-Love shells for designing cellular tshin-shell structures with excellent damage tolerance ability is proposed.This method utilizes high-order continuous nonuniform rational B-splines(NURBS)as basis functions for Kirchhoff-Love shell elements.The geometric and analysis models of thin shells are unified by isogeometric analysis(IGA)to avoid geometric approximation error and improve computational accuracy.The topological configurations of thin-shell structures are described by constructing the effective density field on the controlmesh.Local volume constraints are imposed in the proximity of each control point to obtain bone-like cellular structures.To facilitate numerical implementation,the p-norm function is used to aggregate local volume constraints into an equivalent global constraint.Several numerical examples are provided to demonstrate the effectiveness of the proposed method.After simulation and comparative analysis,the results indicate that the cellular thin-shell structures optimized by the proposed method exhibit great load-carrying behavior and high damage robustness.

Comparison of debris flow susceptibility assessment methods:support vector machine,particle swarm optimization,and feature selection techniques

The selection of important factors in machine learning-based susceptibility assessments is crucial to obtain reliable susceptibility results.In this study,metaheuristic optimization and feature selection techniques were applied to identify the most important input parameters for mapping debris flow susceptibility in the southern mountain area of Chengde City in Hebei Province,China,by using machine learning algorithms.In total,133 historical debris flow records and 16 related factors were selected.The support vector machine(SVM)was first used as the base classifier,and then a hybrid model was introduced by a two-step process.First,the particle swarm optimization(PSO)algorithm was employed to select the SVM model hyperparameters.Second,two feature selection algorithms,namely principal component analysis(PCA)and PSO,were integrated into the PSO-based SVM model,which generated the PCA-PSO-SVM and FS-PSO-SVM models,respectively.Three statistical metrics(accuracy,recall,and specificity)and the area under the receiver operating characteristic curve(AUC)were employed to evaluate and validate the performance of the models.The results indicated that the feature selection-based models exhibited the best performance,followed by the PSO-based SVM and SVM models.Moreover,the performance of the FS-PSO-SVM model was better than that of the PCA-PSO-SVM model,showing the highest AUC,accuracy,recall,and specificity values in both the training and testing processes.It was found that the selection of optimal features is crucial to improving the reliability of debris flow susceptibility assessment results.Moreover,the PSO algorithm was found to be not only an effective tool for hyperparameter optimization,but also a useful feature selection algorithm to improve prediction accuracies of debris flow susceptibility by using machine learning algorithms.The high and very high debris flow susceptibility zone appropriately covers 38.01%of the study area,where debris flow may occur under intensive human activities and heavy rainfall events.

Optimization of Methylene Blue Dye Adsorption onto Coconut Husk Cellulose Using Response Surface Methodology: Adsorption Kinetics, Isotherms and Reusability Studies

In this study, coconut husk cellulose was employed as a cost-effective and environmentally friendly adsorbent to eliminate methylene blue (MB) dye from aqueous solutions. The successful development of response surface methodology paired with a central composite design (RSM-CCD) enabled the optimization and modelling of the adsorption process. The study investigated the individual and combined effects of three variables (pH, contact time, and initial MB dye concentration) on the adsorption of MB dye onto coconut husk cellulose. The developed RSM-CCD model exhibited a remarkable degree of precision in predicting the removal efficiency of MB dye within the specified experimental parameters. This was demonstrated by the strong regression parameters, with an R2 value of 99.79% and an adjusted R2 value of 99.6%. The study depicted that the optimal parameters for attaining a 98.8827% removal of MB dye using coconut husk cellulose were as follows: an initial MB dye concentration of 30 mg∙L−1, contact time of 120 minutes, and pH 7 at a fixed adsorbent dose of 0.5 g. The Freundlich isotherm model provided the most satisfactory description of the equilibrium adsorption isotherms, suggesting that MB dye adsorption onto coconut husk cellulose occurs on a heterogeneous surface. The experimental results demonstrated a strong agreement with the pseudo-second-order kinetics model, indicating that the number of active sites present on the cellulose adsorbent predominantly influences the adsorption process of MB dye. Additionally, the adsorbent made from coconut husk cellulose exhibited the potential to be reused, as it retained its efficiency for a maximum of three cycles of adsorption of MB dye. The results of this study show that coconut husk cellulose has the potential to be an effective and sustainable adsorbent for removing MB dye from aqueous solutions.

The Key Path of the Shape Optimization Design of Isotropic Material Pressure Vessels

An optimization design was conducted for the shape of the pressure vessel with a thin-shell shell. During this process, the optimization calculation was performed with the aid of the genetic algorithm toolbox included in Matlab. Firstly, through the parametric modeling function of APDL, models such as arc-shaped, parabolic, elliptical, and those generated by the fitting curve command were successfully constructed. Meanwhile, the relevant settings of material properties were accomplished, and the static analysis was conducted. Secondly, the optimization calculation process was initiated using the genetic algorithm toolbox in Matlab. Eventually, through analysis and judgment, the model generated by the fitting curve command was relatively superior within the category of the best shape.

Optimization of Cellulose Nanocrystal Isolation from Ayous Sawdust Using Response Surface Methodology

This study focuses on the extraction of cellulose nanocrystals (CNC), from microcrystalline cellulose (MCC), derived from Ayous sawdust. The process involves multiple steps and a large amount of chemical products. The objective of this research was to determine the effects of factors that impact the isolation process and to identify the optimal conditions for CNC isolation by using the response surface methodology. The factors that varied during the process were the quantity of MCC, the concentration of sulfuric acid, the hydrolysis time and temperature, and the ultrasonic treatment time. The response measured was the yield. The study found that with 5.80 g of microcrystalline cellulose, a sulfuric acid concentration of 63.50% (w/w), a hydrolysis time of 53 minutes, a hydrolysis temperature of 69˚C, and a sonication time of 19 minutes are the ideal conditions for isolation. The experimental yield achieved was (37.84 ± 0.99) %. The main factors influencing the process were the sulfuric acid concentration, hydrolysis time and temperature, with a significant influence (p < 0.05). Infrared characterization results showed that nanocrystals were indeed isolated. With a crystallinity of 35.23 and 79.74, respectively, for Ayous wood fiber and nanocrystalline cellulose were observed by X-ray diffraction, with the formation of type II cellulose, thermodynamically more stable than native cellulose type I.

ISO 15189全面质量管理体系下临床生化领域比对方案应用

目的基于ISO 15189建立的全面质量管理体系,探讨临床生化实验室涉及的多种比对方案,为日常检验工作正确使用比对方案提供参考。方法参照医学实验室认可相关文件、国家相关卫生行业标准、CLSI系列相关文件、结合工作实践经验,对临床生化领域比对活动中多种质量评估方案的应用进行分析,梳理总结其中涉及的比对方案。结果本研究针对临床生化领域中涉及的11种比对实验进行了列举总结,比对结果分别满足不同情况的要求。结论通过对不同比对方案的梳理及案例分析,能够指导日常检验工作比对方案的正确选择,提高实验室检验质量和能力。

国际标准化组织(ISO)管理模式和运行机制初探

本文简要回顾了国际标准化组织(ISO)的历史和发展,概述了ISO的管理模式,强调了ISO的核心价值观及其作用与重要性。从灵活、多样的办公模式,人性化的人力资源培养与储备模式,以及营造工作—生活平衡的整体运行环境等三个方面,阐述了ISO的运行机制。为我国深入了解ISO内部管理和运行机制,更好地理解ISO决策和思维模式,进而更好地履行我国作为ISO常任理事国职责,更高效地参与其活动并开展工作提供借鉴与参考。

ISO 11798:2023《信息与文献纸张上书写、打印和复印图像的耐久性和耐用性要求与测试方法》标准解读

ISO11798:2023规定了长期保存在图书馆、档案馆等可控环境中纸质文献的书写、打印、复印图像的耐久性和耐用性的要求与测试方法,不仅为图书馆、档案馆等单位更好地开展纸质文献保护工作提供助力,同时也为出版印刷行业提高印刷质量提供了重要参考。本文详细介绍了最新版ISO11798标准的修订背景、修订过程以及主要修订内容,希望能为相关从业人员研究新标准文本及制定相应国家标准提供帮助。

ISO针灸国际标准建设概况与特点分析

目的:分析国际标准化组织(international organization for standardization,ISO)针灸国际标准建设的概况与特点,为进一步推进针灸国际标准化建设提供依据,以促进针灸疗法的推广、应用与国际交流。方法:对ISO官网中针灸相关标准进行检索,并分析其特点。结果:目前ISO已发布的针灸相关标准共19项,包括器具标准13项、术语标准5项、安全标准1项;正在研制中的针灸相关标准共6项,包括器具标准3项、术语标准1项、安全标准2项。结论:ISO针灸国际标准制定快速增长,涉及的领域逐步扩大;ISO针灸相关标准以器具标准为主,安全标准仅涉及器具安全;ISO针灸相关国际标准的推广和应用有待提高。

将ISO15189质量管理体系融入医学检验技术专业本科实习的教学模式探讨

通过让医学检验专业的临床实习生模拟整个ISO15189认可过程,有助于实习生全面、深入的了解质量管理体系的各个环节,有助于其就业后能尽快投入到单位的质量管理工作中去。经过ISO15189实战培训的实习生,理论学习和实践操作能力均得到提高。该教学方法为培养高水平的医学检验人才提供临床实习带教新模式,并为用人单位定向培养指定岗位人才开辟新的教学途径。

ISO 15489-1:2016《信息与文献文件(档案)管理概念与原则》的修订预研进展

ISO 15489-1的基本介绍I SO 15489-1由国际标准化组织信息与文献标准化技术委员会档案(文件)管理分技术委员会(以下简称“ISO TC46/S C11”)最早发布于2001年,是全球第一个关于文件管理的国际标准,综合了世界各国文件管理的先进经验,吸收了国际公认的最优化文件管理方法,具有较强的先进性、前瞻性和实用性。该标准是ISOT C46/SC11所制定系列标准的基础标准,现已被全球50多个国家采用,并先后被翻译超过22余种语言。经过10余年的应用、持续研究与改进、审核与咨询,2016年,ISO发布了15489-1:2001的修订版。

基于ISO标准的颜色便捷控制与体系化交流模式

印刷技术的发展与颜色的控制息息相关,借用数字化模式降低颜色再现时主观判断的难度,是印刷行业一直坚持探求的目标。ISO/TC 130为印刷行业奠定了系统化的颜色交流模式与体系,本文探讨了基于ISO标准的颜色便捷控制与体系化交流模式。

ISO汉信码Unicode模式详解

2021年8月27日,国际标准化组织(ISO)和国际电工委员会(IEC)正式发布ISO/IEC 20830:2021《信息技术自动识别与数据采集技术汉信码条码符号规范》(Information technology-Automatic identification and data capture techniques-HanXin Code bar code symbology specification)。为帮助我国条码与自动识别技术产业界深入理解该标准中Unicode模式的技术实现方法,解决应用该模式进行信息编码的问题,本文详细介绍了汉信码Unicode模式的设计思路与编解码技术方案,并给出了编码实例进行解释和说明。

基于多IRS辅助的MU-MISO系统安全通信方案

在无线通信系统中,智能反射面(intelligent reflecting surface,IRS)可以调控反射单元的相移来反射信号,用于增强用户信号并抑制窃听者信号,解决基站和用户之间的安全通信问题。针对该问题,以系统加权和保密速率最大化为目标提出一种多IRS辅助多用户多输入单输出(multi user-multiple input single output,MU-MISO)系统的安全通信方案。该方案首先将最大化加权和保密速率问题分解为发射波束形成和人工噪声向量优化、多IRS相位矩阵优化的两个子问题;其次,采用半定松弛、引用文献定理、辅助变量替换、一阶泰勒近似等方法,将每个子问题转换为简单凸问题进行求解;最后,基于交替优化算法依次求解两个凸优化子问题。数值仿真结果表明,与另外三个方案相比,所提方案可以有效增强系统的安全通信性能,并表明了多IRS部署比单个IRS可以实现更好的系统安全性。

Comparison of differential evolution, particle swarm optimization,quantum-behaved particle swarm optimization, and quantum evolutionary algorithm for preparation of quantum states

Four intelligent optimization algorithms are compared by searching for control pulses to achieve the preparation of target quantum states for closed and open quantum systems, which include differential evolution(DE), particle swarm optimization(PSO), quantum-behaved particle swarm optimization(QPSO), and quantum evolutionary algorithm(QEA).We compare their control performance and point out their differences. By sampling and learning for uncertain quantum systems, the robustness of control pulses found by these four algorithms is also demonstrated and compared. The resulting research shows that the QPSO nearly outperforms the other three algorithms for all the performance criteria considered.This conclusion provides an important reference for solving complex quantum control problems by optimization algorithms and makes the QPSO be a powerful optimization tool.

ISO 15189:2012和ISO 15189:2022的不符合对照分析及换版策略

目的通过分析ISO 15189:2012与ISO 15189:2022版标准的不符合项,为实验室换版工作提供改进策略。方法收集24家实验室32次现场评审的522项ISO 15189:2012不符合项目,并将其对应到ISO 15189:2022版标准的相关条款。基于标准要求、文献研究和实验室现状,探讨ISO 15189换版的工作策略。结果每次现场评审平均16条不符合项,最少8条,最多31条。这些不符合项主要集中在ISO 15189:2022版7.3检验过程(165条)、6.5设备校准和计量学溯源(43条)、6.6试剂和耗材(40条)等条款要求。而对于风险管理、患者相关要求、即时检验等新增或加强的条款要求,不符合项相对较少。结论ISO 15189:2022版标准的不符合项主要集中在检验过程环节,建议实验室利用数字化、智能化技术手段,加强这一环节的管理,以顺利实施新版标准要求,并通过组织培训、差距分析、文件修订、全员参与实施、加强风险管理和持续改进等策略,确保换版工作的顺利推进。

基于ISO-TW算法的多仓储机器人路径规划研究

针对当前智能仓库中多仓储机器人协同规划效率低下、动态性不足等问题,提出了一种融合改进蛇优化(Improved Snake Optimizer,ISO)算法和时间窗(Time Window,TW)模型的路径规划方法。首先,在静态规划阶段,利用考虑阻塞因素的改进蛇优化算法为多仓储机器人规划出全局最优路径,同时计算出各机器人的时间窗,从而提升仓储机器人的规划效率;其次,在动态规划阶段,通过建立的多仓储机器人时间窗模型并引入动态调节策略,以消解冲突提升算法的动态性能;最后,进行仿真及实验。仿真结果表明,ISO-TW算法相较其他算法在阻塞点数量上最多可减少27~43个,减少幅度达22.50%~31.62%(机器人规模为80个);重规划路径比重可降低39.82%~41.05%(机器人规模为40个);平均运行时长最多可缩短38~40 s,缩短幅度约为18.27%~19.05%(机器人规模为60个)。实验结果表明,ISO-TW算法较其他算法平均运行时长减少8.53%~9.23%,冲突次数减少11.63%~15.56%,能够在真实场景中实现多仓储机器人的高效协同规划。