中小型钢铁企业生产物流分段管理模式及其应用

分析了中小型钢铁企业生产物流管理存在的普遍问题和生产物流的特点,建立以CPFR思想指导的生产物流管理规范和例外事件处理机制。应用JIT和MRPⅡ二种现代生产管理理论,构建了一套针对中小钢铁企业的生产物流推-拉分段管理模式:以MRPⅡ为主线,采用推式生产模式,进行连续生产阶段的生产计划的制定和生产物流控制;以JIT为主线,采用拉式生产模式,进行离散生产阶段的生产物流控制。X集团应用效果表明了该模式对生产物流相关指标改善的有效性。     

枢纽港—物流港联动的罗泾港区规划设计创新

新近建成的上海港罗泾港区是集矿石、煤炭、钢铁等散杂货物为一体的综合性港区,是世界上第一座公共港区为大型钢铁企业提供分拨配送等增值服务的物流港区。罗泾港区规划设计开发了全新的“枢纽港—物流港”联动的平行结构平面布置模式。在传统的公用港口布置方法基础上,运用准时制（JIT）的精益生产（LP）物流理念,优化装卸工艺和港口平面布置,提升服务水平,延伸港口服务链条;实现了物流流程的高度一体化、同步化;节约了极为宝贵的深水岸线和土地资源、降低了能耗。     

JIT采购的园区供应模式分析

运用系统优化思想和数学方法,在EOQ模型中引入物流成本因素,指出在传统的供应方式下,运输成本与库存成本存在替代性,小批量供应达不到经济订购批量.采用园区供应和制造商取货制后,通过合理调度,消除了运输成本与库存成本的替代性,小批量供应能够达到经济订购批量.特别地,采用本地园区供应模式,可以实现同期供货,供应链得以按照彻底的JIT方式生产.     

中、少批量生产中JIT拉式生产的实现

在中、少批量生产的制造过程中之所以推行JIT拉式生产比较困难是因为不存在实现JIT所必需的流水线.本文对中、少批量生产中如何实现拉式生产进行探讨,通过应用成组技术对生产进行流程再造,组建(虚拟)成组生产单元,进行必要的平衡调整后,在单元内部创建类似大量生产的准流水线,进而在其上按JIT的原则组织生产就可以得到拉式生产的好处.并根据国内实际情况探讨了企业的精益改造与信息化相结合的具体做法.     

JavaScript引擎JIT代码的类型混淆缺陷检测器

类型混淆漏洞是近期在JavaScript引擎中集中爆发的一类漏洞。但是,受即时编译(JIT)代码的限制,以往的类型混淆缺陷的检测方法,无法用于检测JavaScript引擎JIT代码的类型混淆缺陷。本文提出了一种针对该类型缺陷的检测方法,并实现了检测器名为TC-JIT-San的JIT代码类型混淆缺陷检测器。该方法利用JIT代码执行流和数据类型之间关联性,将从JIT代码中识别数据类型的难题转为观察执行流的变化。TC-JIT-San通过观察执行流的变化情况是否符合正常执行逻辑,从而检测出类型混淆缺陷。实验结果表明,TC-JIT-San具有低开销、低漏报和误报的特点。其运行时开销是正常执行的1.84倍,平均漏报率和误报率为0%和0.11%。     

经济订货批量研究

以企业生产物流中的库存管理为切入点,通过批量折扣的双箱系统模型,定量地分析了需求的再订购批量和折扣批量之间的关系。指出了JIT的局限性,并且简要地介绍了新型的库存管理方法一VMI(供应商管理用户库存),同时提出了一些见解。     

产业集群环境下中小企业基于B2B平台的联合JIT采购

通过利用中小企业产业集群化所带来的邻近优势,构建了一种适合中小企业实施的联合JIT采购模式,分析了其框架结构与参与主体,提出了中小企业产业集群联合JIT采购的运作流程,并以浙江嘉兴茧丝绸中小企业实施JIT采购的案例进行了介绍说明,最后就联合JIT采购可能存在的障碍、风险及应对策略进行了分析。     

及时生产制(JIT)应用的探讨

实施JIT生产制的目的是降低库存和消除浪费。实现这一目的的手段是看板管理。看板管理需要一定的基础条件,看板管理的运用必须理解看板的概念、看板的运作程序以及应该注意的问题。实施JIT生产制是一个持续改进过程。     

用正交试验设计法实现JIT系统的仿真优化

为降低企业推行JIT(Just-In-Time)的风险和成本,探讨了影响JIT系统性能的相关因素,运用中间变量建立了JIT系统的仿真模型;采用正交试验设计法选择仿真的优化因子,不仅考虑了因子对系统性能的影响,同时考虑了其经济性;结合企业实例,对JIT系统不同阶段优化方向的选择问题进行了进一步的探讨。     

基于Just-ln-Time的CIM

CIM和JIT是最近二十几年发展起来的两种主要制造模式。本文讨论了两种模式的主要思想及处理变故的特点。JIT强调减少浪费和简化,CIM强调集成和柔性。结合两者的优点,我们提出一种基于JIT的CIM模式,并针对我国实情,讨论了引进JIT和CIM的策略。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...