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991.
The ultrastructural form of the measurement error model is considered and a comparison of the direct and the reverse regression
estimators is made under the balanced loss function, which explicitly takes into account the accuracy of the predictions and
the precision of estimation. 相似文献
992.
Harriet Black Nembhard Ming Shu Kao 《Quality and Reliability Engineering International》2001,17(4):307-321
Nonconforming parts are often produced when a process moves from one level to another due to transition events. Control charting, when applied to a stable state process, is an effective monitoring tool to continuously check for process shifts or upsets. However, the presence of transition events can impede the normal performance of traditional control chart with increased false alarms. The presence of autocorrelation also requires modification to the control charting procedure. We present a methodology for characterizing the process transition which involves a tracking signal statistic, based on the forecast‐based exponentially weighted moving average (EWMA). This test will supplement the forecast‐based EWMA control charting as a means of detecting when the transition event is complete. Such a procedure facilitates smooth application of the appropriate control chart by knowing when the transition is over. The transition characterization methodology also carries benefits in cost and material savings. We use a color transition process in plastic extrusion to illustrate a transition event and demonstrate our proposed methodology. Simulation is employed to evaluate the performance of the methodology. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
993.
994.
Boal BV and the University of Twente participate in research projects focused on improvement of die design methods for aluminum extrusion dies. Within this research empirical knowledge is combined with insights gained from numerical process simulations. Design rules for improvements to the geometry and functionality of flat and porthole dies have been defined. For porthole dies this has led to enhanced die stability and significant reduction of scrap. For both flat and porthole dies an increase in production speed and a reduction of wear has been obtained. This paper will describe the scope of this research and present results achieved in industrial practice. 相似文献
995.
齿轮轴冷挤压工艺及模具设计 总被引:5,自引:0,他引:5
叙述了采用冷挤压工艺代替切削加工生产齿轮轴的优点,并对齿轮轴零件进行了工艺分析。拟制了冷挤压前的毛坯处理及设计了冷挤压模具结构。 相似文献
996.
Water solubilities and octanol/water partition coefficients are widely used to predict partitioning and bioconcentration phenomena for hydrophobic organic pollutants in aqueous systems. This paper is the first in a two part series describing the application of high performance reverse phase liquid chromatography (HPRPLC) for indirect estimation of these two physicochemical parameters to facilitate environmental fate and transport predictions for organic compounds. In the first part, thermodynamic factors which control partitioning processes, water solubilities, and reverse phase retention behavior are discussed, and models for interlinking these three properties are summarized. The second part presents the results of aqueous solubility and octanol/water partition coefficient predictions for a number of organic contaminants from measurements of their HPRPLC behavior, and compares the modeling capabilities of some of the theoretical partitioning/solubility equations developed in the first paper. 相似文献
997.
反循环钻孔灌注桩钻进技术探讨 总被引:1,自引:0,他引:1
介绍了机械成孔灌注桩的类型,探讨了反循环钻进工艺的原理,归纳了反循环钻进的优点,列出了反循环常规钻进参数,详细地阐述了钻孔垂直度控制、钻孔坍塌控制及复杂地层钻进工艺,以完善反循环钻孔灌注桩钻进技术。 相似文献
998.
Keith A. Scudamore Robin C. E. Guy Brian Kelleher Susan J. MacDonald 《Food Additives & Contaminants》2008,25(3):331-337
In the European Union, deoxynivalenol in cereals and cereal products is controlled by recent legislation with the objective of minimizing consumer exposure to this mycotoxin. Relatively few studies have examined the loss of Fusarium mycotoxins during processing and whether this is accurately reflected by the processing factors. The behaviour of deoxynivalenol, nivalenol and zearalenone during extrusion of naturally contaminated wholemeal wheat flour has been examined using pilot-scale equipment. Factors examined were temperature and moisture content. Concentrations of the three mycotoxins were little changed by extrusion although the amount of deoxynivalenol decreased at the lowest moisture content. However, this effect did not appear to be temperature-dependent, suggesting that the apparent loss is either due to binding or inability to extract the residue. Under some conditions, concentrations of the mycotoxins, particularly nivalenol, were higher after extrusion. 相似文献
999.
Effect of Process Conditions on the Physical and Sensory Properties of Extruded Oat-Corn Puff 总被引:2,自引:0,他引:2
ABSTRACT: The effect of processing variables, including screw speed (200,300, and 400 rpm), moisture content (18, 19.5, and 21%), and four different percentages (55,70,85, and 100%) of oat flour, on the extrudate physical properties (expansion, bulk density, and texture profiles) and sensory properties were studied. Increasing the percentage of oat flour resulted in extrudates with a lower specific length, higher bulk density, lower lightness, higher redness, lower yellowness, higher hardness, and lower springiness, gumminess, and chewiness. Higher moisture content reduced expansion, except for the 100% oat flour puffs. Screw speed had no significant effect on the bulk density, specific length, and expansion ratio. Principal Component Analysis showed that decreasing moisture content and increasing screw speed resulted in increased product temperature, which was highly correlated with attributes of a more expanded product such as lightness, crispness, shininess, and an open cell structure. With a higher screw speed and a higher product temperature, corn-related flavors were more likely to develop. High correlations between physical and sensory properties were observed. 相似文献
1000.
阻燃、聚醚型聚氨酯热塑弹性体在野外特种用途通信电缆中的应用 总被引:1,自引:1,他引:0
介绍了野外特种用途通信电缆使用的特殊要求,论述了产品结构设计和材料选用的特点,重点论述如何选用阻燃、聚醚型聚氨酯热塑弹性体替代氯丁橡胶,作为电缆的外护套。文中较详细介绍了聚醚型聚氨酯的特性、应用和选用,以及挤出工艺特点和注意事项。 相似文献