The effect of doubly tapered strut morphology on the plastic yield surface of cellular materials

Although the literature on the mechanics of cellular materials is vast, there is no theoretical model to account for the effects of axial yielding of struts aligned to the applied loading direction on the plastic yield surface under multiaxial loading conditions. An anisotropic hexagonal model having tapered strut morphology is developed to show these effects on the plastic yield surface under multiaxial tensile loading condition. This model covers several types of cellular structure such as two-dimensional (2D) hexagonal and square cellular materials, and three-dimensional (3D) hexagonal and rhombic cellular materials of rod-like columnar structure. A tetrahedral element with tapered strut morphology is also used for a foam model to illustrate these effects on the yield surface under axisymmetric loading condition. Plastic collapse due to bending moment in the inclined struts is a dominant mode. However, under multiaxial tensile loading, the collapse due to axial yielding of struts parallel to the loading direction is found to be an important mode. The shape of plastic yield surface was found to depend not only on relative density but also on the strut morphology.     

Yield Stress and Microstructure of Set Yogurt Made from High Hydrostatic Pressure-Treated Full Fat Milk

ABSTRACT: Set yogurts were prepared from fortified milk subjected to the following processes: (a) Thermal process (85C,°C,35 min), (b) High hydrostatic pressure process (193 or 676 MPa for 5 or 30 min), and (c) Nonprocessed milk (control). Yogurts from milk treated with 676 MPa for 30 min exhibited similar yield stress and water-holding capacity (WHC) to yogurts from heated milk. Transmission Electron Microscopy (TEM) micrographs exhibited small round casein micelle aggregates without appendages in yogurts from heated milk. Yogurts from milk treated with 193 MPa and untreated milk exhibited low yield stress, low WHC, and large clusters of coalesced micelles. Mechanisms for gel formation are discussed.     

技术攻关提高成材率

介绍了广钢集团高速线材生产线的生产和工艺概况，分析了成材率的影响因素，阐述了技术攻关提高成材率所采取的措施和取得的良好效果及经济效益。     

提高超小型铝电解电容器生产一次合格率

恰当选择原材料、确保铆接工序质量、重视工作电解液的配比、严控各工序成品率是提高超小型铝电解电容器投入产出一次合格率的关键。以１０Ｖ－４７μＦ（４ｍｍ×７ｍｍ）产品为例，投入产出一次合格率达９４％以上。     

Compressive Stress-Strain Relationships of Two Puffed Cereals in Bulk

The compressive stress-strain relationships of two puffed cereals, rice and corn based, in bulk were determined using a Universal Testing Machine. The general sigmoid shape of the relationship could be described by a four parameter empirical model originally developed for cellular solids. Jaggedness could be expressed in terms of an apparent fractal dimension and/or the mean magnitude of the power spectrum determined using the Fast Fourier Transform. Both measures as well as a particular parameter of the empirical model were sensitive indicators of the changes in the stress-strain relationships resulting from exposure to different relative humidities. Although the stress strain relationship, especially of dry samples, had an irregular, irreprodu-cible shape, the magnitude of the two roughness measures was highly reproducible.     

中子产额大于1.5×10^10n／s的密封中子管

报道了一种中子产额大于１．５×１０１０ｎ／ｓ、靶和离子源都可拆卸的密封中子管，以它为核心研制的密封中子发生器已被用于中子照像等领域，并取得了较好的结果。     

Dynamics of Solidification in 2% Corn Starch-Water Mixtures: Effect of Variations in Freezing Rate on Product Homogeneity

Directional solidification studies of gelatinized corn starch-water mixtures were undertaken in order to examine, in situ, the freezing behavior of this food model. The solidification rate was controlled by varying sample cell velocity as it moved from a 25°C hot stage to a -25°C cold stage. While freezing at cell velocities ≤7.5 μm/sec, starch granules were alternately pushed or entrapped by the advancing solid-liquid interface producing a segregated structure consisting of alternating high-starch and low-starch bands. At a cell velocity of 10 μm/sec, the frozen product was homogeneous. The relationship between the solid-liquid interface velocity and segregation behavior was quantified and compared to an existing model of particle-interface interactions.     

Testing multi-characteristic product capability indices

Recently, studies associated with testing the quality and performance of each process for a product with multi-characteristics are proposed more often. However, most studies are limited to discussing one single type of quality characteristic. Practically, a multi-characteristic product is potentially composed of three types: smaller-the-better, larger-the-better, and nominal-the-best. In this paper, we propose an integrated product capability index which considers these three different types of quality characteristics. According to the theory of testing hypothesis, we develop a testing procedure for the product capability index to judge whether the process capabilities of total quality characteristics meet the customers’ demands. In addition, the relationship between the product capability index and the yield of the entire product will be introduced. Finally, an example is provided as a practical application.