316L化合搅拌桨制取硫酸锰溶液时的耐腐蚀性

假设在电解金属锰和电解二氧化锰行业的化合工序制取硫酸锰溶液时,均采用316L不锈钢材质的化合搅拌桨。探讨该材质在不同工艺要求和不同工艺环境下,分析其在化合硫酸浓度、反应温度、搅拌转速、工艺要求等方面带给桨叶的腐蚀速率和腐蚀量,为化合搅拌桨选材和设计提供可行性研究。结果表明:温度对316L不锈钢影响最大,316L搅拌桨在电解二氧化锰行业高温情况下和在电解金属锰行业低温情况下,前者腐蚀速率、腐蚀量要高出2倍以上,且腐蚀掉的铁含量给后续的去杂和制液生产等工艺带来不利的影响。

Visualization and simulation of plastic material flow in friction stir welding of 2024 aluminium alloy plates

Thin copper sheets as marker material were embedded into weld path of 2024 aluminium alloy plates and their final position after friction stir welding was examined by metallographic techniques. Referring to the visualized material flow patterns, a three-dimensional model was developed to conduct the numerical simulation of the temperature profile and plastic material flow in friction stir welding. The calculated velocity contour of plastic flow in close proximity of the tool is generally consistent with the visualized results. As the tool rotation speed increases at a constant tool travel speed, the material flow near the pin gets stronger. The predicted shape and size of the weld nugget zone match with the experimentally measured ones.

单质起爆药本质安全连续自动化生产技术

论述了单质起爆药的连续自动化生产技术、安全保障技术、多参数精确控制的配料技术、化合多参数综合控制技术、在线自动筛选、称量、装盒技术、防爆机械手自动传输技术、隔爆防爆技术和本质安全技术等多项关键技术突破情况,实现了单质起爆药生产过程的自动化合计量加料、多参数控制化合、负压水洗、在线烘干、自动筛选计量装盒以及液态、固态自动物流传输等。

Friction stir welding of aluminum to copper—An overview

Components made by joining different materials are required in various engineering applications.Fabrication of suchcomponents is a challenging task due to the vast difference in mechanical,thermal and electrical properties of the materials beingused.Friction stir welding(FSW)is capable of joining dissimilar materials such as aluminum(Al)and copper(Cu)and thereforeresearchers have used this novel process for dissimilar joining.Consequently,several works pertaining to dissimilar joining,specifically Al?Cu,are available in the literature but they are scattered in different sources,which makes the task of gatheringinformation about dissimilar FSW of Al?Cu cumbersome.This work has been written with an aim to provide all pertinentinformation related to dissimilar FSW of Al?Cu at one place to ease the problems of researchers.It comprehensively covers andsummarizes the topics such as the effect of tool design and geometry,FSW process parameters,FSW strategies on mechanicalproperties,microstructure and formation of defects during dissimilar FSW of Al?Cu.In addition,it also presents and discussesseveral variants of dissimilar FSW of Al?Cu.Finally,this work not only puts forth major findings of the previous researchers but alsosuggests future recommendations for dissimilar FSW of Al?Cu.

Effects of Slow-Mixing on the Coagulation Performance of Polyaluminum Chloride （PACI）

Conventional jar tests and on-line size monitoring were used to investigate the effects of slow-mixing intensity and duration on residual turbidity and floc size during charge neutralization coagulation and sweep floc- culation with polyaluminum chloride. The compensatory effect of slow-mixing on coagulation performance fol- low!ng inadequate_or excessive rapid-mi_xing was also examined. It is found that slowTmixing intensity has a more marked positive ettect on charge neutralization coas;ulatlon tlaan on sweep tlocculatlon. llle optimal root-mean- square velocity gradient, G, for slow-mixing is 15 s-＇ for both coagulation mechanisms, and charge neutralization coagulation requires a longer slow-mixing duration. The optimal slow-mixing duration, based on residual turbidity,is longer than the time to tbrm the largest mean Ilocs. The optimal product of G and mixing duration, GT, lbr slow-mixing during charge neutralization coagulation （13500） are higher than that during sweep flocculation （4500） and both are less than the range of values recommended by the American Water Works Association （24000-84000）.The optimal GT value under various slow-mixing conditions increases with G. Appropriate extension＇of slow-mixing duration during charge neutralization coagulation can improve coagulation performance after an inadequate or excessive rapid-mixing duration, but during sweep flocculation, appropriate shortening of slow-mixing duration after an excessive rapid-mixing or appropriate extension of slow-mixing duration after an inadequate rapid-mixing is favorable.

An aligned mixture probabilistic principal component analysis for fault detection of multimode chemical processes

A novel approach named aligned mixture probabilistic principal component analysis(AMPPCA) is proposed in this study for fault detection of multimode chemical processes. In order to exploit within-mode correlations,the AMPPCA algorithm first estimates a statistical description for each operating mode by applying mixture probabilistic principal component analysis(MPPCA). As a comparison, the combined MPPCA is employed where monitoring results are softly integrated according to posterior probabilities of the test sample in each local model. For exploiting the cross-mode correlations, which may be useful but are inadvertently neglected due to separately held monitoring approaches, a global monitoring model is constructed by aligning all local models together. In this way, both within-mode and cross-mode correlations are preserved in this integrated space. Finally, the utility and feasibility of AMPPCA are demonstrated through a non-isothermal continuous stirred tank reactor and the TE benchmark process.