数控机床分布式远程监测系统的研究

提出一种数控机床的分布式远程监测设计方案,在总体设计时把系统分成底、中、顶三层,重点讨论CORBA和W eb Service相结合的中间件技术。     

基于MCU的水泥抗折试验机的研制

介绍了一种基于MCU、压力传感器和直流电机的水泥抗折试验机的新方案及实现,分别从方案原理、硬件、软件和控制算法四个方面对系统进行了详细的阐述.该系统利用微控制器的高速计算能力,对施加在水泥试块上的载荷实施在线监控并调节电机转速,使得加荷速度控制在国标范围内,实现了抗折试验机的全自动运行和数据记录,亦达到了小型化的目的.     

污水厂A/O除磷出水为基质的Anammox小试研究

为研究污水处理厂厌氧氨氧化(Anammox)工艺可行性,在实际生活污水处理厂中进行厌氧氨氧化工艺的小试实验.向污水厂A/O除磷工艺出水中投加亚硝酸盐作为基质,启动厌氧氨氧化滤柱.反应器启动成功后,进水改为A/O除磷和亚硝化工艺处理后的生活污水,观察厌氧氨氧化工艺实际工程应用的效果.结果表明,第106~144天,进水温度为15~20℃,最大出水氨氮和总氮质量浓度为4.1和13.4 mg/L,出水氮素满足国家一级A排放标准;第168~204天,反应器运行进入冬季,进水温度为12~15℃,采用延长水力停留时间的方法实现污水处理达标;第222~240天时,水温降低到10~12℃,在进水投加125 mg/L碳酸氢钠,总氮去除负荷提高了40%,最大出水氨氮和总氮质量浓度为1.4和13.6 mg/L,冬季出水氮素达标.在整个过程中滤柱生物膜厚度持续增加,最终达113μm,单位MLSS污泥厌氧氨氧化负荷大于5 kg/(kg·d),厌氧氨氧化工艺在市政污水处理厂高效稳定运行.     

污水处理厂SAD工艺小试运行研究

为提高反应器的氮素去除率,在市政污水处理厂进行同步厌氧氨氧化反硝化(SAD)工艺小试.以A/O除磷和亚硝化工艺处理后的生活污水为基质,启动厌氧氨氧化滤柱.反应器启动成功后,基质中投加有机碳源促进反硝化菌生长,启动SAD工艺,研究碳源质量浓度对SAD工艺的影响.由于葡萄糖对厌氧氨氧化菌抑制作用较小,成本较低,作为SAD工艺的有机碳源.结果表明:常温条件下,进水分别投加10,20和30 mg/L Glu,SAD工艺耦合效果良好,平均出水总氮质量浓度为9. 16,8. 10和6. 41 mg/L.相较于厌氧氨氧化工艺,SAD工艺出水总氮质量浓度降低了16%~42%,常温条件下取得了良好的运行效果.冬季水温为10~12℃,基质中投加30 mg/L Glu,SAD工艺稳定性受到破坏并向反硝化工艺转变,出水氨氮质量浓度由0. 5 mg/L增长至6. 2 mg/L.水温对SAD工艺有较大影响,低温条件下SAD工艺中厌氧氨氧化菌与反硝化菌的竞争中占据劣势,工艺稳定性受到破坏.将基质Glu质量浓度降低到20 mg/L,出水总氮质量浓度为6. 5~8. 5 mg/L,冬季SAD工艺出水氨氮和总氮质量浓度满足北京市地方标准的A类排放标准.     

Drilling machinability of engineering ceramics under low-frequency axial vibration processing by sintering/brazing composite diamond trepanning bit

Thin-wall diamond trepanning bits are extensively used for processing hard and brittle materials such as engineering ceramics. However, it is difficult to achieve high-efficiency processing of engineering ceramics at a constant feed speed, because of high dynamic compressive strength, high hardness, and low density of engineering ceramics. In this study, a novel composite diamond bit combining sintering and brazing has been designed, along with the low-frequency axial vibration technology, to realize the continuous hole processing of engineering ceramics. Drilling experiments have been conducted on Al₂O₃ and SiC engineering ceramics with a constant feed speed. The variation of axial force, micromorphology of hole wall surface drilled, as well as the method of removing nesting during the drilling process were analyzed. According to the results, the novel composite diamond bit fabricated by combining sintering and brazing, can achieve the continuous hole processing of engineering ceramics at a constant feed speed, including Al₂O₃ and SiC. Compared to the conventional drilling (CD), the low-frequency axial vibration drilling (LFVD) can significantly reduce the axial force, and produce fewer plastic scratches on the hole wall surface drilled. In particular, the automatic blanking ratio approaches to 100% by LFVD, and only about 73.58% by CD. It can be concluded that LFVD technology can be used to realize continuous hole processing of engineering ceramics. The research results achieved in this study show that the drilling machinability of engineering ceramics by LFVD and novel composite diamond bit is good. Accordingly, this study provides a useful reference for continuous processing or batch production of engineering ceramics at a constant feed speed.     

Adsorption studies of Pb (II) by two different magnetic MnFe2O4 materials synthesized with sol-gel process

Abstract

The spherical nanomaterials of MnFe-Ac and MnFe-Na can be synthesized with sol-gel method. The adsorption test of Pb (II) was carried out with two kinds of synthesized nanomaterials, and discussed their adsorption effects of Pb (II). The characteristic was analyzed by SEM, XRD, XPS and magnetic measurements. As the results showeed, the particles size of the material became smaller, but the morphology did not change after adsorption. The change of Ms was from 42.7 and 62.0?emu/g to 25.6 and 89.4?emu/g, respectively. By Langmuir and Freundlich models, the maximum adsorption amounts of Pb (II) were 23.40 and 41.56?mg/g, respectively, and analysis demonstrated that the adsorption of Pb (II) on samples was monolayer adsorption. The kinetic analysis showed that the adsorption of Pb (II) on the two materials was more in accordance with the pseudo-second-order model, which indicated that adsorption process of the materials for Pb (II) were primarily limited by the chemical adsorption.     

Through-thickness permeability modelling of woven fabric under out-of-plane deformation

When a woven fabric is subject to a normal uniform loading, its properties such as tightness and through-thickness permeability are both altered, which relates to the fabric out-of-plane deformation (OPD) and dynamic permeability (DP). In this article, fabric OPD is analytically modelled through an energy minimisation method, and corresponding fabric DP is established as the function of loading and fabric-deformed structure. The total model shows the permeability a decrease for tight fabric and an increase for loose fabric when the uniform loading increases. This is verified experimentally by fabric OPD, static and dynamic permeabilities. Experimental tests for both permeabilities showed good agreement with the corresponding predictions, indicating the fact that tight fabric becomes denser and loose fabric gets more porous during OPD. A sensitivity study showed that an increase of fabric Young’s modulus or a decrease of fabric test radius both lead to an increase of DP for tight fabric and opposite for loose fabric. The critical fabric porosity and thickness were found for inflexion of fabric DP trend during the OPD, which contributes to the optimum design of interlacing structure applied to protective textiles and composites.     

提升立式混合机安全和可靠性的最新控制方法

在某大型立式混合机控制系统设计过程中,为提升立式混合机安全性和可靠性,首次设计和集成大量最新的控制方法和技术.控制技术包括药温防爆红外热成像技术、混合锅远程应急下降控制技术、转矩高速采集记录技术、操作追溯技术和校时技术等,同时,在设计过程中加强原有安全性功能设计,如联锁控制功能设计和防误操作功能设计等.结果表明:该设计大幅提升了立式混合机的安全性和可靠性,适宜于在我国已装备的数百台(套)立式混合机系统中做技术升级,具有较强的针对性和推广价值.