炸药乳化器安全监测方法及其发展

文章回顾了几种现行的乳化器安全运行检测方法,分析了各自的优缺点,介绍了一种使用现代振动监测诊断技术对乳化炸药生产线的关键设备乳化器进行在线安全监测的基本原理和功能,讨论了乳化器安全监测系统的发展方向.     

高强聚烯烃静态断裂过程银纹区的性能1.HDPE

为了观察分析高密度聚乙烯(HDPE)的银纹区性能,对两种HDPE全切痕试样分别进行了速率为0.1 mm/min,0.5 mm/min,1 mm/min,5 mm/min,20 mm/min和50 mm/min的拉伸测试。基于对静态断裂过程应力-位移数据的分析处理,结果表明,HDPE的屈服应力随着拉伸速率增大;高应力时两种HDPE均存在常临界位移控制其银纹断裂;HDPE2480银纹微纤的稳定性较大,材料韧性较好。HDPE静态拉伸断面显微结构显示,HDPE2480的银纹微纤尺寸大于HDPE4801,导致两者断面弧形巢尺寸和弧形巢内粗糙度的不同。     

全层片状TiAl基合金断裂过程的原位观察

利用ＳＥＭ拉伸台，研究了Ｔｉ－３３Ａｌ－３Ｃｒ－０．５Ｍｏ合金的室温拉伸断裂动态过程。试验结果表明，具有全层片状显微组织的ＴｉＡｌ合金室温断裂韧性较高，归因于合金拉伸过程中裂纹尖端发生分叉致使应力松弛而使裂纹钝化；在变形过程中，主裂纹尖端附近的微裂纹之间形成剪切韧带，剪切韧带韧化是ＴｉＡｌ合金的一种韧化机理。     

Can porous polymeric scaffolds be functionalized by stem cells leading to osteogenic differentiation? A systematic review of in vitro studies

The aim of this study was to analyze the influence of nanoporous structure of polymeric biomaterials on the in vitro osteogenic induction of human stem cells. An electronic search in three databases (MEDLINE, SCOPUS, and Web of Science) was performed for articles that were published before May 2018. In vitro studies were included if they met the following criteria: (1) the use of polymeric scaffolds (natural or synthetic); (2) the co-culture of human stem cells with the scaffold; and (3) cell viability, proliferation, and osteogenic differentiation assays. The main characteristics of the published studies were summarized, and a quality assessment tool was used to analyze methodological features. Eighty-eight potential articles were firstly retrieved. Thirteen were eligible for qualitative analysis. Only three studies characterized cell stemness. Nanostructure of the scaffolds showed a significant influence on viability, proliferation, and osteogenic differentiation of human stem cells. Combination of porosity between 72 and 93% and a large range diameter between 50 and 224 μm resulted in more remarkable cellular proliferation and differentiation. Porous polymeric scaffolds can be functionalized by stem cells leading to osteogenic induction. High standards of laboratory practice and accurate methodological reporting are essential for the credibility of the results.     

Synthesis of TiO2 nanopellet by TiCl4 as a precursor for degradation of RhodamineB

In the present investigation in order to promote TiO₂ pellet structure and its photocatalytic activity, two new precursors were synthesized in the powder and sol forms, using sol–gel method with precipitation of TiCl₄. Since TiO₂ pellets are normally synthesized by the commercial TiO₂ powder (DegussaP25), in this investigation and in the first step a new synthesized TiO₂ powder was produced and compared with DegussaP25. Subsequently, two types of pellet were made by the new synthesized powder and titania sol. The characterization of the synthesized TiO₂ powder and pellet were performed by XRD, FT-IR, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The result showed that by the new procedure utilized here, without using any additive not only the surface area of the produced TiO₂ powder has been increased, but also the crystalline phase is completely in the anatase form. It was also found that the synthesized pellets by the sol precursor had better morphological structure than the synthesized pellets by theTiO₂ powder (either DegussaP25 or new synthesized powder). Ultimately, in order to evaluate photocatalytic activity of TiO₂ powders and pellet, degradation of RhodamineB was tested.     

FMS machine loading: A simulated annealing approach

In this paper the problem of FMS machine loading is considered with the objective of minimizing the system imbalance using a simulated annealing (SA) approach. New job sequences are generated with a proposed perturbation scheme named the 'modified insertion scheme' (MIS). These sequences are used in the proposed simulated annealing algorithm to arrive at a near global optimum solution. A new approach for temperature variation in the SA algorithm is also suggested in which temperature is assumed to be parabolic. The SA algorithm using the proposed MIS and the assumed temperature variation proved to be giving substantial improvement in system imbalance as against conventional sequences.     

Non-linear analysis for anisotropic materials

An elasto-plastic analysis of anisotropic work-hardening materials, using the finite element method is presented. The analysis is based on the generalized Huber-Mises yield criterion extended by Hill for anisotropic materials. General expressions for the anisotropic parameters in the yield criterion have been derived both for initial yielding as well as subsequent yielding in the case of work-hardening materials. The isoparametric ‘quadratic’ quadrilateral elements have been used for the analysis and the ‘initial stress technique’ has been adopted for the iterative solution of the non-linear problems. The results of the various numerical examples have been compared with the available solutions.     

Semi-empirical Density Estimations for Binary,Ternary and Multicomponent Alkali Nitrate–Nitrite Molten Salt Mixtures

For sensible thermal energy storage in Concentrating Solar Power (CSP) plants, a molten salt mixture of 60 wt% sodium nitrate (NaNO₃) and 40 wt% potassium nitrate (KNO₃), known as Solar Salt, is commonly utilized. The paper presents semi-empirical estimation results of the density of Solar Salt and alternative molten salt mixtures with low melting temperatures in a range from 70 °C to 140 °C. These mixtures are Hitec, HitecXL, LiNO₃–KNO₃–NaNO₃ and a multicomponent mixture. The paper shows that density values of mixtures can be closely predicted from single salt densities. The paper examines different estimation rules for mixtures. The quasilinear volumetric additivity rule (QVAR) is known for ternary reciprocal systems. For the first time, the presented work extends the QVAR to multicomponent mixtures. Temperature-dependent densities of selected salt mixtures of the system Ca,Li,K,Na//NO₂,NO₃ were estimated. Estimations are motivated by a fast and reliable method compared to time-consuming and error-prone measurements of several mixtures.