基于供应链资源整合下的非混装配送模式探讨

全球供应链的重新整合影响国际贸易的运行模式,国内物流行业面对急剧变化市场的冲击和物流成本不断抬升,行业的生存空间逐步被挤压,传统凭经验配载装车、安排运输配送车辆、规定路线的运营模式弊端日益突出。物流企业迫切需要培养能够通过不断计算优化配送方案,在整合供应链资源下提升企业物流分配效率的人才;解决传统的分配求解方法中,计划法容易产生“组合爆炸”的问题,实现物流配送成本最优化。

球团矿和生块矿混送试验

为使处于满负荷作业状态的直拨料系统满足生产的需要,韶钢创造性地提出了将生块矿、球团矿按炼铁生产炉料结构中生块矿、球团矿的使用量同比例混合送料的生产组织管理新模式,并于2002年11月27日至12月6日在4号高炉进行了球团矿和生块矿混送工业试验,试验效果较好,达到了预期目的。

基于资源整合的连锁超市混搭配送优化研究

如何合理地将低温商品和常温商品进行混搭配送,从而以最低的成本,最高的效率,最优的服务,将多品种货物及时完好地送达各门店是连锁超市配送面临的主要问题。本文在物流资源整合的基础上,综合考虑物流配送的库存成本、运输成本、能耗成本和惩罚成本等,建立了利润最大化的混搭配送物流优化的数学模型,利用模拟退火算法求解,并进行了实证研究分析。研究表明,基于资源整合的混搭配送可以提高服务水平和利润,这说明,混搭配送可有效地解决中小超市物流配送的高成本和低效率问题。

Experimental Study of Sediment Incipience Under Complex Flows

Sediment incipience under flows passing a backward-facing step was studied. A series of experiments were conducted to measure scouring depth, probability of sediment incipience, and instantaneous flow velocity field downstream of a backward-facing step. Instantaneous flow velocity fields were measured by using Particle Image Velocimetry (PIV), and an image processing method for determining probability of sediment incipience was employed to analyze the experimental data. The experimental results showed that the probability of sediment incipience was the highest near the reattachment point, even though the near-wall instantaneous flow velocity and the Reynolds stress were both much higher further downstream of the backward-facing step. The possible me- chanisms are discussed for the sediment incipience near the reattachment point.

Preliminary Results of Assessing the Mixing of Wave Transport Flux Residualin the Upper Ocean with ROMS

The effects of the mixing of wave transport flux residual(Bvl) on the upper ocean is studied through carrying out the control run(CR) and a series of sensitive runs(SR) with ROMS model.In this study,the important role of Bvl is revealed by comparing the ocean temperature,statistical analysis of errors and evaluating the mixed layer depth.It is shown that the overestimated SST is improved effectively when the wave-induced mixing is incorporated to the vertical mixing scheme.As can be seen from the vertical structure of temperature 28℃ isotherm changes from 20 min CR to 35 m in SR3,which is more close to the observation.Statistic analysis shows that the root-mean-square errors of the temperature in 10 m are reduced and the correlation between model results and observation data are increased after considering the effect of Bvl.The numerical results of the ocean temperature show improvement in summer and in tropical zones in winter,especially in the strong current regions in summer.In August the mixed layer depth(MLD) which is defined as the depth that the temperature has changed 0.5℃ from the reference depth of 10 m is further analyzed.The simulation results have a close relationship with undetermined coefficient of Bvl,sensitivity studies show that a coefficient about 0.1 is reasonable value in the model.

The latest progress in research of plastics processing technology

According to the great demand for the＂ green＂ plastics processing technology of the low energy consumption, high efficiency and environmental protection in plastics industry, the plastics processing method and technology based on the elongation rheology, with continuing evolution and innovation of the plastics plasticating and conveying method, are presented and researched on the basis of the plastics dynamic processing method arid equipment, and the plastics plasticating and conveying process in the vane extrusion system, the technical characteristics and the applications of vane plasticating and conveying technology are discussed. The research results show that compared with the conventional processing equipment, this new technology and equipment shows many outstanding advantages, such as shortening the thermo-meehanical history of the plastics processing by more than 50 % , reducing the energy consumption by 30 % or so, improving the mixing and blending effects, improving the quality of the products and the adaptability to materials, etc. , and it is found that the new technology and equipment has special superiority in the fields of the processing for material systems, such as the multiphase and multicomponent composite materials, the shear heat sensitive macromolecular materials, etc.

发展中的混装冷藏配送技术

随着人们生活水平的提高以及物流业的发展，冷冻冷藏品运输占据了越来越重要的位置。世界各国的发展历程表明，冷冻冷藏运输业的发展与GDP增长密切相关，当GDP达到一定水平时，冷冻冷藏运输业就会出现一个飞跃性的增长，这预示着我国的低温物流必将逐步迈上快车道。

Reconstruction of an Expert＇s Decision Making Expertise in Concrete Dispatching by Machine Learning

Finding the optimum solution for dispatching in concrete delivery is computationally intractable because it is a NP-hard （non-deterministic polynomial-time hard） problem. Heuristic methods are required to obtain satisfactory solutions. Inefficiencies in mathematical modeling still make concrete dispatching difficult to solve. In reality, complex dispatching systems are mostly handled by human experts, who are able to manage the assigned tasks well. However, the high dependency on human expertise is a considerable challenge for RMC （ready mixed concrete） companies. In this paper, a logical reconstruction of an expert＇s decision making is achieved by two machine learning techniques： decision tree and rule induction. This paper focuses on the expert dispatcher＇s prioritization of customer orders. The proposed method has been tested on a simulation model consisting of a batch plant and three customers per day. The scenarios generated by the simulation model were given to a dispatch manager who was asked to prioritize the customers in each day. The scenarios and the decisions were then input to the machine learning programs, which created generalizations of the expert＇s decisions. Both decision trees and rules approach 80% accuracy in reproducing the human performance.

Impact of Prevailing Wages on the Cost among the Various Construction Trades

In 1997, the Ohio Senate passed Senate Bill 102 which established the Ohio School Facilities Commission as a separate agency to oversee the rebuilding projects of the public schools in Ohio. The bill also exempted the construction contractors from paying prevailing wages on these projects on the hypothesis that this exemption would lower the construction cost. The purpose of this study is to investigate this hypothesis through the statistical analysis of 8,093 bids received from the years 2000 through 2007 for the schools＇ construction. Union contractors who paid their workers union wages and non-union contractors who did not pay prevailing wages bid these projects. The hypothesis, that prevailing wage laws increased the construction cost, was tested by comparing the bids/SF （square foot） from both groups （union and nonunion） for the different construction trades. The study indicated that there was statistical significant difference between the bids/square foot for union contractors and the bids/square foot for non-union contractors for only the following trades： earthwork, existing conditions, plumbing, electrical and HVAC （heating, ventilation and air conditioning）. The averages of bids/SF from the union contractors were higher than those from the non-union contractors for earthwork, existing conditions and plumbing works, and the opposite for electrical and HVAC works. There was no statistical significant difference in the bids from the communications, concrete, conveying equipment, electronic safety and security, equipment, finishes, fire suppression, furnishings, masonry, openings, structural steel, thermal and moisture protection, plastics and composites and wood works.

Optimal air-supply mode of hybrid system with radiant cooling and dedicated outdoor air

The hybrid system with radiant cooling and dedicated outdoor air not only possesses high energy efficiency, but also creates a healthy and comfortable indoor environment. Indoor air quality will be improved by the dedicated outdoor air system(DOAS) and indoor thermal comfort can be enhanced by the radiant cooling system(RCS). The optimal air-supply mode of the hybrid system and the corresponding design approach were investigated. A full-scale experimental chamber with various air outlets and the ceiling radiant cooling panels(CRCP) was designed and established. The performances of different air-supply modes along with CRCPs were analyzed by multi-index evaluations. Preliminary investigations were also conducted on the humidity stratification and the control effect of different airflow modes to prevent condensation on CRCP. The overhead supply air is recommended as the best combination mode for the hybrid system after comprehensive comparison of the experiment results. The optimal proportion of CRCP accounting for the total cooling capacities in accord with specific cooling loads is found, which may provide valuable reference for the design and operation of the hybrid system.

A successful case of hydrocarbon dew point analysis during mixing of natural gases in transmission pipeline

The occurrence of liquid condensation in natural gas accounts for new challenges during the interoperability between transmission networks,where condensation would lead to higher pressure drops,lower line capacity and may cause safety problem.A successful case of hydrocarbon dew point(HCDP)analysis is demonstrated during the mixing of natural gases in the transmission pipeline.Methods used to predict the HCDP are combined with equations of state(EOS)and characterization of C6+heavy components.Predictions are compared with measured HCDP with different concentrations of mixed gases at a wide range of pressure and temperature scopes.Software named"PipeGasAnalysis"is developed and helps to systematic analyze the condensation problem,which will provide the guidance for the design and operation of the network.

Macro and micro issues in turbulent mixing

Numerical prediction of turbulent mixing can be divided into two subproblems: to predict the geometrical extent of a mixing region and to predict the mixing properties on an atomic or molecular scale, within the mixing region. The former goal suffices for some purposes, while important problems of chemical reactions(e.g. flames) and nuclear reactions depend critically on the second goal in addition to the first one. Here we review recent progress in establishing a conceptual reformulation of convergence, and we illustrate these concepts with a review of recent numerical studies addressing turbulence and mixing in the high Reynolds number limit. We review significant progress on the first goal, regarding the mixing region, and initial progress on the second goal, regarding atomic level mixing properties. New results concerning non-uniqueness of the infinite Reynolds number solutions and other consequences of a renormalization group point of view, to be published in detail elsewhere, are summarized here.The notion of stochastic convergence(of probability measures and probability distribution functions) replaces traditional pointwise convergence. The primary benefit of this idea is its increased stability relative to the statistical "noise" which characterizes turbulent flow. Our results also show that this modification of convergence, with sufficient mesh refinement, may not be needed. However, in practice, mesh refinement is seldom sufficient and the stochastic convergence concepts have a role.Related to this circle of ideas is the observation that turbulent mixing, in the limit of high Reynolds number, appears to be non-unique. Not only have multiple solutions been observed(and published) for identical problems, but simple physics based arguments and more refined arguments based on the renormalization group come to the same conclusion.Because of the non-uniqueness inherent in numerical models of high Reynolds number turbulence and mixing, we also include here numerical examples of validation. The algorithm we use here has two essential components. We depend on Front Tracking to allow accurate resolution of flows with sharp interfaces or steep gradients(concentration or thermal), as are common in turbulent mixing problems. The higher order and enhanced algorithms for interface tracking, both those already developed, and those proposed here, allow a high resolution and uniquely accurate description of sample mixing problems. Additionally, we depend on the use of dynamic subgrid scale models to set otherwise missing values for turbulent transport coefficients, a step that breaks the non-uniqueness.

The Study of Latent Heat Transport Characteristics by Solid Particles and Saccharide Solution Mixtures

The purpose of this study is the development of latent heat transport system by using the mixture of the minute latent heat storage materials and the saccharine solution as medium. The experimental studies are carried out by the evaluation of viscosity and pressure loss in a pipe. Polyethylene (P.E.) is selected as the dispersed minute material that has closeness density (920kg/m3) of ice (917kg/m3). D-sorbitol and D-xylose solutions are picked as continuum phase of the test mixture. The concentration of D-sorbitol solution is set 48mass% from measured results of saturation solubility and the melting point. 40mass% solution of D-xylose is selected as the other test continuum phase. The non-ion surfactant, EA157 Dai-ichiseiyaku CO. Ltd, is used in order to prevent of dispersed P.E. powder cohere. The pressure loss of test mixture is measured by the straight circular pipe that has smooth inner surface. The measuring length for pressure loss is 1000 mm, and the inner diameter of pipe is 15mm. The accuracy of experiment apparatus for measuring pressure loss is within ±5%. The pressure loss data is estimated by the relationship between the heat transport ratio and the required pump power. It is clarified that the optimum range of mixing ratio exists over 10mass% of latent heat storage material.