The roles of conceptual modelling in improving construction simulation studies: A comprehensive review

The conceptual modelling phase of simulation studies has proven to be effective in enhancing the impact of simulation modelling in different domains. However, this simulation phase did not receive much attention in the construction simulation domain. The objective of this paper is to identify the roles that conceptual modelling can play in advancing the engagement, accuracy, and adoption (among other things) of discrete-event simulation studies in construction. In this paper, a Systematic Literature Review (SLR) is conducted, which involves a comprehensive search of databases and researchers’ profiles to identify journal papers, conference articles, books, and theses that have reported the benefits of conceptual modelling for discrete-event simulation studies. The review resulted in 82 documents that were published from 2000 to 2020. Results indicate that the benefits of conceptual modelling include facilitating communications between stakeholders, capturing sufficient information for the simulation model, improving the quality of simulation models, guiding other simulation modelling activities, and facilitating verification and validation of simulation models. By linking these benefits to the current research agenda in construction simulation, this paper shows the significance and potential of the conceptual modelling phase to enhance the impact of discrete-event simulation studies in construction.     

高落差粉尘扩散规律和分布特征

高溜井放矿过程中会形成强大的冲击气流引起粉尘扩散，造成严重的井下环境污染，对其进行有效治理一直是井下通风除尘的工作重心，本工作利用相似实验和数值模拟相结合的方式探究溜井放矿过程中粉尘的扩散规律和分布特征。通过改变放矿质量、矿石粒径、溜井密闭程度、含水率等因素测试不同条件下气流大小和粉尘浓度分布，并利用CFD-DPM耦合方法模拟卸矿过程中的气?固两相流，研究气流和粉尘浓度时空分布特征。结果表明，最大粉尘浓度和风速随放矿质量增加而上升，随颗粒粒径和溜井密闭程度增大而降低，且含水率越大，粉尘浓度越小，风速无明显变化，在放矿过程中矿石颗粒之间碰撞占主导作用，颗粒流呈横向分布。     

潮流能水平轴水轮机在剪切来流下的水动力分析

采用基于计算流体力学方法的全尺度数值模拟计算,建立了适用于潮流能水轮机模拟的剪切来流环境,通过数值计算结果,对潮流能水轮机随时间变化的宏观力和流场特征进行了系统分析,探索水轮机在复杂工况下的水动力特性规律。结果表明,水轮机整个叶轮的总体平均受力在剪切流工况中未受到明显影响; 单个叶片的瞬态轴向力系数和瞬态轴向扭矩系数在旋转周期内出现了明显的周期性变化,且周期性变化幅值随转速增大而增大; 非定常的瞬时轴向扭矩和力的周期性振荡容易引起单个叶片的结构性振动,可能对水轮机的机械结构造成影响。     

极薄、超宽规格装甲板压力淬火工艺数值模拟优化

利用数值模拟的方法对极薄、超宽规格装甲板淬火过程的畸变进行了模拟研究,并对脉冲式压力淬火的控制参数进行了优化。通过对比不同冷却条件装甲板的变形量,确定了脉冲式压力淬火的脉冲压力和周期。结果表明,脉冲约束的模拟条件下,装甲板在厚度Z方向上的最终变形量为1.7 mm,不仅小于2 mm的标准要求,而且可以实现装甲板的小淬火畸变前提下满足其表面无压痕、划痕等其他损伤的实际生产需求。     

埋地管道泄漏内封堵装置设计与研究

针对流体输送埋地管道泄漏问题,设计了一种利用管道机器人携带封堵气囊进行快速应急封堵修复的埋地管道泄漏内封堵装置。采用矩阵变换方法建立了牵引系统驱动轮过弯方程,利用MATLAB软件对过弯方程进行了验证,同时利用ADAMS软件仿真分析过弯路径与驱动轮转角对牵引系统行走速度的影响。研究结果表明:由两个串联封堵器组成的应急封堵系统可满足复杂工况下的管道泄漏封堵要求;牵引系统驱动轮在弯管内部行走时,单轮速度呈周期性变化,但三个驱动轮整体周期运动特性一致;驱动轮转角在25°~40°时,牵引系统行走速度与驱动轮转角成正比,且转角为30°时驱动效果最好。该内封堵装置的结构设计可为管道泄漏应急封堵领域装备的研发提供重要参考。     

基于AMESim的液压马达加载系统研究

液压马达作为液压系统的执行元件在工程机械上广泛应用,针对液压马达加载工况下的输出特性,利用Simulink和AMESim软件对系统进行联合仿真建模,并对系统的运行状态、控制性能、回收性能进行研究,对液压马达加载系统的设计和改进具有重要的参考意义。     

地表移动带范围内建构筑物安全可靠性分析

地表建构筑物位于在生产矿山地表开采移动范围内，如果按照一般圈定地表移动范围原则判断建构筑物的安全可靠性，结果是不安全或者预留保安矿柱可保证安全。为分析地表移动带范围内建构筑物安全可靠性，采用FLAC3D软件建立数值模拟模型，对矿区地表移动进行分析研究，并结合建构筑物的破坏等级评判标准，可以更加合理地判断地表移动范围内建构筑物的安全可靠性，对存在相似条件的矿山具有一定的借鉴意义。     

齐大山铁矿南帮含水构造带探测研究

为解决采空区突发涌水给矿山安全生产带来的安全威胁,以齐大山铁矿为研究对象,以高密度电阻率法含水构造带理论模型的正演模拟研究为基础,运用高密度电阻率法对采场南帮含水构造带的异常范围进行了圈定;运用瞬变电磁法进行了二次探测,并对高密度电阻率法所圈定的异常范围进行了验证。研究表明:含水构造带显示为低阻异常特征,在高密度电阻率法探测成果图中显示的两处低阻异常与含水构造带理论模型的正演模拟结果一致;同时,在瞬变电磁法探测成果图中显示的低阻区域均在高密度电阻率法所圈定的低阻异常范围内,二者相互验证,这两处低阻异常均为含水构造带的地球物理异常特征的显示,表明采用高密度电阻率法和瞬变电磁法组合识别技术可实现对隐伏含水构造带的先导性探测。     

Genes Identification,Molecular Docking and Dynamics Simulation Analysis of Laccases from Amylostereum areolatum Provides Molecular Basis of Laccase Bound to Lignin

An obligate mutualistic relationship exists between the fungus Amylostereum areolatum and woodwasp Sirex noctilio. The fungus digests lignin in the host pine, providing essential nutrients for the growing woodwasp larvae. However, the functional properties of this symbiosis are poorly described. In this study, we identified, cloned, and characterized 14 laccase genes from A. areolatum. These genes encoded proteins of 508 to 529 amino acids and contained three typical copper-oxidase domains, necessary to confer laccase activity. Besides, we performed molecular docking and dynamics simulation of the laccase proteins in complex with lignin compounds (monomers, dimers, trimers, and tetramers). AaLac2, AaLac3, AaLac6, AaLac8, and AaLac10 were found that had low binding energies with all lignin model compounds tested and three of them could maintain stability when binding to these compounds. Among these complexes, amino acid residues ALA, GLN, LEU, PHE, PRO, and SER were commonly present. Our study reveals the molecular basis of A. areolatum laccases interacting with lignin, which is essential for understanding how the fungus provides nutrients to S. noctilio. These findings might also provide guidance for the control of S. noctilio by informing the design of enzyme mutants that could reduce the efficiency of lignin degradation.     

Sequence-Dependent Nanofiber Structures of Phenylalanine and Isoleucine Tripeptides

The molecular design of short peptides to achieve a tailor-made functional architecture has attracted attention during the past decade but remains challenging as a result of insufficient understanding of the relationship between peptide sequence and assembled supramolecular structures. We report a hybrid-resolution model to computationally explore the sequence–structure relationship of self-assembly for tripeptides containing only phenylalanine and isoleucine. We found that all these tripeptides have a tendency to assemble into nanofibers composed of laterally associated filaments. Molecular arrangements within the assemblies are diverse and vary depending on the sequences. This structural diversity originates from (1) distinct conformations of peptide building blocks that lead to different surface geometries of the filaments and (2) unique sidechain arrangements at the filament interfaces for each sequence. Many conformations are available for tripeptides in solution, but only an extended β-strand and another resembling a right-handed turn are observed in assemblies. It was found that the sequence dependence of these conformations and the packing of resulting filaments are determined by multiple competing noncovalent forces, with hydrophobic interactions involving Phe being particularly important. The sequence pattern for each type of assembly conformation and packing has been identified. These results highlight the importance of the interplay between conformation, molecular packing, and sequences for determining detailed nanostructures of peptides and provide a detailed insight to support a more precise design of peptide-based nanomaterials.