Supply chain network design under the risk of uncertain disruptions

Facility disruptions in the supply chain often lead to catastrophic consequences, although they occur rarely. The low frequency and non-repeatability of disruptive events also make it impossible to estimate the disruption probability accurately. Therefore, we construct an uncertain programming model to design the three-echelon supply chain network with the disruption risk, in which disruptions are considered as uncertain events. Under the constraint of satisfying customer demands, the model optimises the selection of retailers with uncertain disruptions and the assignment of customers and retailers, in order to minimise the expected total cost of network design. In addition, we simplify the proposed model by analysing its properties and further linearise the simplified model. A Lagrangian relaxation algorithm for the linearised model and a genetic algorithm for the simplified model are developed to solve medium-scale problems and large-scale problems, respectively. Finally, we illustrate the effectiveness of proposed models and algorithms through several numerical examples.     

Porous 3D printed concrete beams show an environmental promise: a cradle-to-grave comparative life cycle assessment

3D Concrete Printing (3DCP) is a rapidly expanding area in the field of architecture, engineering, and construction, but very limited research has quantitatively investigated its environmental impact. The existing Life Cycle Assessment (LCA) studies on 3DCP lack clearly defined functional units of comparison, especially considering load-bearing structures. This paper investigates the potential environmental benefits of 3DCP over conventional concrete construction for structural beams based on a cradle-to-grave comparative LCA. Unlike existing studies, this paper employs a recarbonation model to account for the carbon offsetting from the use-stage of 3DP concrete, which shows significant results. The assessment includes three-beam designs, each analyzed for both prefabrication and on-site construction scenarios. While currently, 3DCP has a generally higher environmental impact due to the larger quantity of cement employed in the process, the reduction of material through infill optimization for printed beams is a promising design principle to positively offset the environmental impacts in the construction sector. The paper draws recommendations for future research on material- and recarbonation-efficient 3DCP design for load-bearing structures, as well as on material development, e.g. integration of larger aggregates and low-clinker cement.

Graphical abstract

     

沸石改性去除有机污染物吸附动力学教学实验探究

采用分光光度法探究了天然沸石与NaCl改性沸石对有机染料的吸附性能,以此建立了其吸附动力学方程,并采用扫描电镜对吸附前后沸石的表面形貌进行了表征,揭示了吸附材料表面结构与其吸附性能间的联系。本教学实验的开展,启发了学生如何采用合适的实验手段来建立并验证相关的吸附动力学方程,加深了学生对材料表面结构与性能联系的认知,强化了学生对界面化学相关理论的理解,有利于创新人才的培养。     

ZnO溶胶改性的玻璃中空纤维膜制备及其染料分离性能研究

将聚偏氟乙烯和钠硼硅玻璃粉先后加入到N,N-二甲基乙酰胺中形成铸膜液,采用干-湿法纺丝和高温烧结处理得到玻璃中空纤维膜,然后在膜上涂覆ZnO溶胶得到ZnO改性的玻璃中空纤维膜.涂覆ZnO溶胶的膜对碳素、刚果红和亚甲基蓝截留率分别为98.65％、98.08％和55.62％,与基膜相比,ZnO溶胶的涂覆促进了染料的截留.此外还测试了涂覆ZnO溶胶膜的长期稳定性,也表现出了对刚果红染料高效的去除率.     

FairFuzz-TC: a fuzzer targeting rare branches

International Journal on Software Tools for Technology Transfer - FairFuzz is a coverage-guided mutational fuzzing tool based on AFL, which targets its mutation strategy towards rare branches in...     

Fast and Robust Stochastic Structural Optimization

Stochastic structural analysis can assess whether a fabricated object will break under real-world conditions. While this approach is powerful, it is also quite slow, which has previously limited its use to coarse resolutions (e.g., 26 × 34 × 28). We show that this approach can be made asymptotically faster, which in practice reduces computation time by two orders of magnitude, and allows the use of previously-infeasible resolutions. We achieve this by showing that the probability gradient can be computed in linear time instead of quadratic, and by using a robust new scheme that stabilizes the inertia gradients used by the optimization. Additionally, we propose a constrained restart method that deals with local minima, and a sheathing approach that further reduces the weight of the shape. Together, these components enable the discovery of previously-inaccessible designs.     

铝合金表面MoSi2／SiC复合涂层的激光熔覆制备

利用激光熔覆技术在铝合金表面制备MoSi2／SiCp复合涂层，对涂层的微观组织形成规律及其主要工艺参数对涂层组织和性能的影响进行了研究。实验结果表明，对试样进行搭接预热和在熔覆粉末中添加助熔剂CaF2是提高熔覆层质量的主要途径。采用多道搭接预热熔覆工艺和预置涂层法可以在铝合金表面获得具有完全冶金结合的原位自生SiC颗粒增韧的硅化钼陶瓷复合涂层，涂层组织主要由Mo（Si，Al）2、SiC、α-Al、Mo5Si3等相组成。熔覆层显微硬度较基体材料的显微硬度有大幅度提高，涂层显微硬度最大可达850HV0.2.     

基于柔性元结构的广义模块化产品族建模及其应用

根据广义模块化设计原理。对广义模块化产品族和产品平台作了整体规划，阐述了柔性模块、虚拟模块、元结构以及柔性元结构等概念，提出了以柔性元结构为基础构建广义模块化产品族的思想。以组合框架式液压机的应用为例，分析了柔性元结构的具体创建过程。实践证明，该方法可以有效加速产品的设计．     

An object-based coding scheme for frontal surface of defective fluted ingot

A novel image-based defect identification and coding technique has been proposed for fluted ingots, which are used for the production of locomotive wheels. The edge density map has been used for defect identification and an object-based coding approach has been applied for the storage of defective ingots. The complete scheme has been implemented in one of the integrated steel plants of India.