A network prototype for integrated production-distribution planning with non-multi-functional plants

This paper proposes a two-echelon network prototype for integrated production and distribution planning where non-multi-functional plants supply multiple types of products with limited quantities to the customers via capacitated warehouses. Four variations of the prototype, formulated as individual mixed integer programming models, are solved using the branch and bound algorithms by numerical experiments to examine the cost implications of production-distribution strategies involving single-sourcing constraints on different levels of the supply chain. Further discussions on the practicality and versatility of the proposed prototype (i.e. its ability to consider different facility locations, specialised capabilities of individual plants, safety stock levels and demand characteristics) illustrate the usefulness of the prototype to industry practitioners when making strategic and/or tactical decisions.     

A Mathematical Model for Vacuum Far-Infrared Drying of Potato Slices

A mathematical model of mass and heat transfer for vacuum far-infrared drying of potato slices is introduced in this study on the basis of energy and diffusion equations. The finite difference method is used to mathematically simulate the sample temperature and moisture content in different drying conditions. Calculated results are compared with the experimental findings at varying conditions of heater temperature (120°C, 140°C, and 160°C), chamber pressure (1500, 8000, and 15000 Pa), sample thickness (0.004, 0.006, and 0.008 m), and radiation distance (0.08, 0.12, and 0.16 m). Comparison results show that the model fits well the changes in sample temperature and moisture content at different times of drying, with the values of the coefficient of determination close to 1.0 and the relative error values less than 10%.     

Microstructural evolution and its influence on creep and stress relaxation in nanocrystalline Ni

Indentation creep and stress relaxation tests were performed on rolled and annealed nanocrystalline (NC) Ni to study the influence of microstructure evolution on plastic deformation behavior. Dislocation density (ρ) increases with increasing rolling strain, reaching a maximum at 20% strain, followed by a decrease at larger strain. The ρ of Ni decreases significantly with increasing annealing temperature. Softening behavior is observed in NC Ni with grain size <40 nm, i.e., an inverse-like Hall–Petch effect. For rolling NC Ni, both creep strain rate and rate sensitivity first increase and then decrease, while those of annealed Ni continuously decrease. With increasing grain size, creep activation volume unusually decreases first, then starts to rise, which is different from that of coarse-grained metal. A model involving dislocation annihilation and emission at grain boundaries under indenters is used to explain the anomalous behavior of rolled and annealed Ni, respectively.     

Synthesis of morphology-controlled mesoporous transition aluminas derived from the decomposition of alumina hydrates

Aluminum hydroxides were synthesized through the acidification of sodium aluminate solution using single organic diester or diacid as pH adjustor and aluminum chelating agent. The obtained alumina hydrates are investigated by XRD, SEM, IR and TG. Bayerite firstly formed at room temperature, and its morphology greatly varied with the pH adjustors used, which probably attributes to different kinetics of the acidification. The bayerite can evolve to gibbsite and boehmite after the hydrothermal treatment at 100 °C and 145 °C, respectively, where these alumina hydrates show diverse morphologies. After the calcination, these alumina hydrates of bayerite, gibbsite and boehmite could pseudomorphically transform to the corresponding η-, χ- and γ-aluminas, respectively, exhibiting different structural and textural properties. Interestingly, the transition aluminas derived from the aluminum tri-hydroxides, bayerite and gibbsite, both display locally organized mesopores, while no such meso-structure can be observed in γ-alumina obtained from the aluminum mono-hydroxide, boehmite. The changes of bayerite during calcination are investigated detailed. The dehydration of non-porous bayerite accompanied with the formation of meso-structured transition aluminas, where the meso-structure becomes more and more clearly defined and pore size expands with the calcination temperature increasing.     

食品防腐剂的使用现状及安全性分析

食品防腐剂主要用于抑制微生物的生长繁殖,以延长食品的保存期。分析了我国食品防腐剂的使用现状、常用的防腐剂的种类及性能、防腐剂使用中存在的问题及安全性评价指标,提出了安全使用防腐剂的建议。     

Composite embedded cubature Kalman filter

The embedded cubature Kalman filter (ECKF) is proven as a kind of algorithm that has higher precision than cubature Kalman filter. Based on the ECKF, a new algorithm, named composite ECKF (CECKF), is presented in this paper. The new CECKF can increase filter precision by means of reusing the embedded cubature rule in the process of numerical approximation, which can realize higher precision than ECKF in theory. At the same time, another new algorithm, named adaptive CECKF, is also put forward by introducing an adaptive method based on CECKF. Through the comparison of simulation, the proposed methods are able to enhance filter precision.     

Cognitive problems,self-rated changes in driving skills,driving-related discomfort and self-regulation of driving in old drivers

Ageing in general is associated with functional decline that may have an adverse effect on driving. Nevertheless, older drivers have been found to show good judgement and to self-regulate their driving, which may enable them to continue driving safely despite functional decline. The process of the self-monitoring of driving ability and the awareness of functional decline, and its association with the self-regulation of driving is, however, not fully understood. The aim of the present study was to examine the perceived changes in driving skills, the discomfort experienced in driving, and the self-regulation of driving as measured by the avoidance of certain driving situations by older drivers with different levels of self-rated cognitive problems. Eight hundred and forty Danish drivers aged 75–95 completed a structured telephone interview. The results showed that the recognition of cognitive problems was associated with an experience of improvement in higher level driving skills but also of a decline in lower level driving skills. Moreover, cognitive problems recognised by drivers were associated with discomfort in, and avoidance of, driving situations. Finally, a linear relationship between discomfort in driving and avoidance was found and this tended to be stronger for drivers recognising cognitive problems. The results indicate that older drivers who recognise problems with cognitive functions display good self-assessment of changes in their driving skills. In addition, the results suggest that driving-related discomfort is an important factor affecting the self-regulation of driving. Finally, the findings indicate that driving-related discomfort functions as an indirect self-monitoring of driving ability and may contribute to the safe driving performance of Danish older drivers.     

基于DTS的汽车检测线异构数据源转换研究

针对汽车检测线控制系统中数据库和数据库表异构现象明显的现状,研究了一种基于DTS的数据源转换技术.首先介绍了SQL Server中用于数据转换的软件组件DTS,分析了异构数据源转换的关键技术；然后利用汽车检测线数据库设计时的各种信息,包括各个表、字段的含义以及数据类型、数据值的约束条件等,通过DTS图形化设计器设计了汽车检测线异构数据源的DTS转换包；最后通过前端VB.net程序调用DTS包对象的Execute方法运行DTS转换包,实现了汽车检测线Access数据源到SQL Server数据源的转换,达到了统一和规范汽车检测线数据源的目的.     

“灯芯效应”下珊瑚骨料混凝土氯离子传输行为

研究了“灯芯效应”下珊瑚骨料混凝土在Mg²⁺、SO₄^2-共同作用下Cl^-的传输规律，建立了“灯芯效应”下珊瑚骨料混凝土Cl^-传输模型.结果表明：Cl^-沿半浸泡混凝土高度方向由下而上传输的同时也由表层向中心传输，其在混凝土内部的含量呈类抛物面分布；SO₄^2-的存在会加快Cl^-在混凝土中的传输，而Mg²⁺的加入会抑制Cl^-的传输，导致混凝土在相同高度及深度处的Cl^-含量小于SO₄^2-与Cl^-共同作用下的Cl^-含量；本文建立的“灯芯效应”下珊瑚骨料混凝土氯离子传输模型计算结果与实测结果吻合良好.     

乔后盐矿斜井溶腔形状初探

斜井三管油垫单井开采在国内为数不多，探讨其溶腔形状及运行参数对安全生产、采矿量计算起到至关重要的指导作用。