基于FlexSim 的军队自动化立体仓库货位优化研究

为提高军队自动化立体仓库出货速度和运行稳定性,提出了在堆垛机闲时对货位进行以分类存储L 形分区为导向的再分配优化设计。根据用户需求,程序自动生成分类存储的L 形分类存储货位分区信息,并调用堆垛机对在存货品逐一判断、搬运,让所有货品按照L 形区域排列,完成货位优化。利用FlexSim 软件对具体实例进行了仿真,结果表明,优化后的货位能较大程度地提高仓库的输出效率。     

自动化立体仓库出入库决策系统的开发与仿真

在对作业方式、出入库作业方式分析的基础上,开发出了自动化立体仓库的出入库决策系统.系统管理层用Visual Basic 6.0编程语言开发,可实现对系统参数的初始设置,记录和查询出入库信息,货位优化管理和堆垛机的优化调度.监控仿真层的开发选用了组态软件组态王6.5,可实现对立体仓库的输入输出作业过程的动态模拟,并对系统运行结果进行曲线分析.系统数据库平台的构建选用的是Access 2000数据库软件,该数据库平台为管理层和监控层搭建了数据桥梁.进行货位优化管理时要综合考虑分布描述指标、库存量指标、出库分发效率指标这三个指标;按照堆垛机作业路线的优先级来安排堆垛机作业指令;综合考虑货位管理、堆垛机调度和输送机的运送管理这三个问题.通过仿真试验证明了可以得到系统进行优化决策方案.     

基于Flexsim的自动化立体仓库出入库仿真与优化

对某制造企业的自动化立体仓库出入库进行了仿真和优化。首先在对该仓库的实际作业进行测录的情况下,收集了各类仿真对象的数据并记录了该自动化立体仓库的出入库及存取作业程序;然后使用Flexsim软件进入仿真,并对仿真运行数据进行分析,写出相应的改善方案;最后再使用Flexsim仿真软件对优化后的仓库进行仿真建模,与优化前的仿真模型输出的数据进行对比分析。结果表明,各个操作台的利用率都比优化前的提高了10%~15%,巷道堆垛机的利用率提高了3%,高层货架货位库存量、货位利用率得到明显提高,各个缓存区的堆积现象明显减少,从而验证了优化方案的可行性。     

基于改进自适应遗传算法求解有色金属立体仓库堆垛机路径优化问题

针对有色金属自动化立体仓库系统,建立其实体模型。通过对遗传算法进行自适应改进,算出能够随时适应的遗传算子,克服了传统遗传算法的早熟收敛问题。通过运用序号法设定各货位在立体仓库中的位置,建立堆垛机拣选作业的数学模型,运用改进遗传算法对初始路径进行改进,得出最优解,并运用Matlab遗传算法工具箱对此进行仿真,实验结果表明,此方法收敛速度快,可以获得全局最优解,其堆垛机路径规划更加快速和有效。     

基于“货到人”拣选系统的动态货位分配研究

目的 为了提高“货到人”拣选系统的订单拣选效率，研究了电商仓库货位初始存储状态为非空情况下的商品货位分配问题。方法 考虑货架上现存商品信息、仓库空余货位数、待补货商品和新收入商品信息，提出基于商品关联度的分散存储策略，以极大化货架上所有存储商品的关联度之和为目标构建商品上架与下架的动态货位分配数学模型，并设计贪婪算法，再采用改进粒子群算法对贪婪算法得到的结果进行优化。结果 基于商品关联度的分散存储策略可以减少货架平均搬运次数29.32%左右。结论 与随机分配策略相比，文中提出的货位分配策略能够有效提升整个电商仓储中心的拣选速度。     

基于最小时间算法的货位优化研究

针对某烟草公司自动化立体仓库的运行现状和结构特点,探讨了货位优化设计原则,建立自动化立体仓库三维数学模型,研究了叉车的运行时间,提出了时间最小的货位优化方法,并获得了重要的计算公式.     

双立柱堆垛机故障诊断关键技术研究

现代物流需要现代仓储体系相配套,现代仓储体系是自动化、高效化的有机结合。双立柱堆垛机是应用于现代立体仓库的重要设备之一,其承担着立体仓库货物的出、入库,在减少仓库的作业人员的同时提高货物的出、入库效率。为了保障双立柱堆垛机的安全、高效的运行,需要积极地做好双立柱堆垛机的研究与分析,尤其是出现在双立柱堆垛机上的各类故障更需要做好记录与分析,并采取针对性的措施予以解决。     

多层棋盘格式立体货架及其货位排布算法研究

为了使立体仓库在更高的空间利用率条件下发挥最大的存取效率和服务能力,对现有立体货架的结构和搬运模式进行了分析,由此提出了一种新型多层立体仓库货架模型,即多层棋盘格式(multilayers chessboard based,MCB)立体货架模型.从二维角度看,MCB立体货架的货位排布方式类似于在矩形棋盘格内摆放棋子问题,针对如何实现MCB排布方式进行了货位排布算法研究,给出了问题描述、数学模型、算法设计,并构建了基于单件多品种随机存储的"棋子算法(chess pieces algorithm,CPA)",对其进行实验验证.实验结果显示"棋子算法"能够合理并有效地解决MCB立体货架的货位排布问题.MCB立体货架能够使单件多品种随机存储立体仓库的空间利用率达到75%以上,并且为实现更高的存储效率奠定基础.     

可变路径人工拣货系统动态货位调整研究

考虑在线零售企业的时变需求,基于逐步求精、渐进式优化的思路,通过实时、动态调整商品在仓库中的存储位置来响应需求的快速变化,并允许拣货员改变其行走路线,在订单拣货的同时进行货位调整。构建了可变路径下动态货位调整框架模型;提出前进和返回交替进行的回转路径策略,并对路径调整策略及商品选择策略两个关键进行研究;通过实验验证模型的有效性。结果表明,在订单规模中等,需求偏度较大时,动态货位调整可节约25%左右的拣货距离,货位优化效果明显,可为在线零售企业科学实施动态货位调整提供理论指导。     

双载具式多层穿梭车立体仓库货位优化研究

目的为提高双载具式多层穿梭车立体仓库的运作效率,对其货位优化进行研究。方法针对双载具式多层穿梭车立体仓库货位优化作业系统的特点,考虑其运动过程中的加(减)速度特性,建立以入库时间最短为目标的货位分配优化模型。通过设计结合交叉变异算子的混合植物繁殖算法对该模型进行优化求解,从而确定最佳货位分配方案,缩短货位分配时间。结果实例分析表明,混合植物繁殖算法与遗传算法和物繁殖算法相比,收敛速度更快、优化效率更高。结论混合植物繁殖算法能够有效地缩短双载具式多层穿梭车立体仓库的货位分配时间,提高了仓库运作效率。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.