Determination of optimal part delivery dates in a stochastic assembly line

We consider the problem of determining the optimal part delivery dates of a low volume, small lot assembly line which manufactures large and costly products. Parts are assembled at each stage to a subassembly. The arrival time of an assembly part from a vendor is assumed to be a normally distributed random variable. A dynamic programming algorithm is developed to minimize work-in-process inventory of parts and subassemblies. It is implemented on the single job problem. Its further extensions to the multi-job case and to incorporate the cost of setting delivery dates are also discussed.     

DIRECTED DIVERGENCE AND CYCLIC SYMMETRY

Abstract

The authors have axiomatically characterized Directed Divergence assuming cyclic symmetry which is weaker than the symmetry.     

Oxycarbide Glasses in the Mg-Al-Si-O-C System

Oxycarbide glasses in the Mg-Al-Si-O-C system were produced at initial carbon levels of 0.0, 0.5, 1.0, 1.5, 2.0, and 2.5 wt%. Carbon was incorporated into the glass melts by means of SiC additions. The glasses were melted between 1750° and 1800°C under nitrogen atmospheres. The limit of carbon incorporation was reached at the 2.5% carbon level, as these glasses crystallized (predominantly cordierite, 2MgO˙2Al₂O₃˙5SiO₂) upon gradual cooling from the meit. Glasses containing less than 2.5% carbon were amorphous according to standard X-ray diffraction methods. Further examination of these oxycarbide glasses by transmission electron microscopy indicated the lack of microcrystalline phases and the potential for producing clear inclusion-free glasses. The Mg-Al-Si-O-C glasses showed significant increases in density, Young's elastic modulus, shear modulus, Vickers hardness, and fracture toughness with increasing carbon content.     

Mullite Crystallization from SiO2-Al2O3 Melts

SiO₂-Al₂O₃ melts containing 42 and 60 wt% A1₂O₃ were homogenized at 2090°C (∼10°) and crystallized by various heat treatment schedules in sealed molybdenum crucibles. Mullite containing ∼78 wt% A1₂O₃ precipitated from the 60 wt% A1₂O₃ melts at ∼1325°± 20°C, which is the boundary of a previously calculated liquid miscibility gap. When the homogenized melts were heat-treated within this gap, the A1₂O₃ in the mullite decreased with a corresponding increase in the Al₂O₃ content of the glass. A similar decrease of Al₂O₃ in mullite was observed when crystallized melts were reheated at 1725°± 10°C; the lowest A1₂O₃ content (∼73.5 wt%) was in melts that were reheated for 110 h. All melts indicated that the composition of the precipitating mullite was sensitive to the heat treatment of the melts.     

Effect of Foliar Application of Auxin on the Quality of Potatoes

Katahdin and Kennebec potatoes were sprayed with 10^?5M auxin at the beginning of flowering. Tubers from the auxin-treated plants were compared with untreated controls for phenolic content, enzymatic discoloration, total nitrogen, nonprotein nitrogen, free ammo acids, lipids, minerals, and ascorbic acid content. In both varieties auxin increased the phenols and enzymatic discoloration. However, no differences were observed in fatty acid composition and ascorbic acid content. Total nitrogen, nonprotein nitrogen, free amino acids, crude lipid, phospholipid and magnesium content were higher, and iron lower, in Katahdin tubers from the treated plants.     

驱动轴系统轴向派生力的测试与计算分析方法

以具有三销轴万向节的驱动轴系统为对象,进行轴向派生力测试,并分析驱动轴系统转速、工作角度、负载转矩和摩擦系数对轴向派生力的影响。基于赫兹接触理论与基于速度的摩擦模型,建立驱动轴系统轴向派生力计算的多体动力学模型。为了提高模型的计算精度,把球环和滚道之间的接触形状视为任意的,且把接触参数和摩擦系数视为随着工况变化而变化的变量。基于有限元分析,提出了一种计算在不同负载扭矩下球环和滚道之间接触刚度和力指数的方法。利用建立的轴向派生力计算模型和试验数据,进一步识别了多种工况下的摩擦系数和接触参数。基于识别的摩擦系数和接触参数,计算了一驱动轴系统的轴向派生力,和试验结果的对比分析表明,模型的计算精度较高。     

New facet of honey bees dancing language for mining the induction rules

Artificial Bee Colony (ABC) algorithm is used in many domains of computation, including optimization, clustering and classification tasks. Further, honey bees dancing is one of the most fascinating and intriguing behaviours of animal life. Honey bees’ dancing is termed as “waggle Dance” in literature and they perform it for indicating the food sources in their environment. This work presents a novel honey bees dancing language (HBDL)-based algorithm for mining the induction rules from datasets. The proposed HBDL algorithm is implemented and tested against the performance of ABC, Particle Swarm Optimization and nine more traditional algorithms frequently used by researchers. The experimental results showed that HBDL is a suitable and effective technique for data mining and classification task.     

Effect of Zinc Fertilization on Yield, Enzymatic Discoloration, Phenolic and Nitrogenous Constituents of Potato Tubers

The effect of zinc fertilization on yield, enzymatic discoloration, phenolic and nitrogenous constituents of Katahdin potatoes was studied. Zinc sulfate was banded in the soil at the time of planting at rates of 0, 20, 40, and 100 1b/acre. Application of 100 1b/acre zinc reduced significantly the total yield and especially U.S. #l yields of potatoes, but no significant differences in yield were observed up to 40 1b/acre zinc sulfate. Zinc fertilization significantly reduced phenolic content and discoloration of tubers. Nonprotein nitrogen and free amino acid contents were reduced at all levels of zinc application, and total nitrogen was significantly reduced at the 100 1b/acre level.