Physical characteristics of conditioned anaerobic digested sludge – A fractal, transient and dynamic rheological viewpoint

The changes in the physical characteristics of unconditioned and conditioned anaerobic digested sludge (ADS) biosolids, such as capillary suction time (CST), yield stress, average size and fractal dimensions, were investigated through a CST test, transient and dynamic rheological test and image analysis. The results showed that the optimum polymer dose range was observed when CST or its reciprocal value was employed as an indicator. There were good correlations between the yield stresses determined from both a controlled shear stress test and a strain amplitude sweep test. The yield stress and storage modulus (G′) increased as the polymer dose increased in most cases. A frequency sweep test revealed that polymer conditioning could extend the frequency sweep ranges for their elastic behaviors over viscous behaviors as well as the gel-like structure in the linear viscoelastic range. These results implied that more deformation energy was stored in this rigid structure, and that elastic behavior became increasingly dominant with the addition of the polymer in most cases. In addition, both the average sizes and two-dimensional fractal dimensions for conditioned ADS biosolids presented a similar up-climax-down variation trend as the polymer doses increased, whereas the critical polymer doses at the highest average sizes or two-dimensional fractal dimensions, were different. Correlation analysis revealed that the conditioned ADS dewaterability was not correlated with the yield stresses, while the average sizes or the two-dimensional fractal dimensions for conditioned ADS biosolids could be taken as the indication parameters for ADS dewaterability.     

瞬态过电压的产生及防护

随着技术的进步,信息设备集成度不断提高,其耐冲击能力却显著降低。导致因雷电产生的雷击电磁脉冲对电子设备的损害成逐年上升趋势。同时电气系统的开关操作和静电放电所产生的瞬态电涌也对电子设备造成极大的危害。瞬态过电压分别产生于开关过程、静电放电和雷电放电。可以通过电流、电感或电容等耦合途径南电源、测量设备或数据传输系统进入电气设备或电子设备内部。室内的导线回路南电源线路和数据线路共同构成,也可以仅由两根数据传输线或者两根电源线构成。感应电压随着感应回路边长的增大而升高。     

多功能静电瞬态电位测试系统

针对动态摩擦作业过程中静电瞬态电位难以测试的情况,设计了多功能静电瞬态电位测试系统.该系统通过模拟室再现各种摩擦状况及环境状况,硬件电路保证信号的实时采集,专用软件解决数据显示和存储的问题.     

基于瞬态分析法的预应力与非预应力钢筋混凝土梁动力响应对比分析*

提出了基于瞬态动力分析完全法的预应力钢筋混凝土梁爆炸冲击模拟方法，并采用已有试验结果验证了方法的合理性，进一步对比探讨了非预应力钢筋混凝土梁与预应力钢筋混凝土梁的动力响应差别和响应机制。研究结果表明：爆炸荷载作用下，钢筋混凝土梁的跨中底部位置最先发生塑性变形，混凝土容易受拉开裂，且爆炸荷载越大开裂越严重；由于预应力筋的存在，预应力钢筋混凝土梁跨中挠度显著减小，预应力钢筋混凝土梁开裂范围大幅减小，裂缝深度也显著降低，但是浅层裂缝的横向分布范围稍有增加；预应力改善了梁的受力状态，使得梁所受荷载均布转移，在爆炸冲击荷载作用下，大部分应力都由预应力筋来承担，非预应力钢筋的应力较小，预应力筋是提高结构抗爆性能的关键点；当脉冲荷载卸载至零后，梁跨中的挠度均能恢复至自重状态下的变形量，说明预应力钢筋混凝土梁在爆炸冲击荷载作用下，仍处于弹性工作状态，这与非预应力钢筋混凝土梁显著不同。模拟研究结果对预应力钢筋混凝土结构抵抗爆炸荷载领域的应用有一定的参考意义。     

射孔爆轰瞬态能量转化及影响因素研究

为有效控制射孔测试联作工况下管柱及封隔器失效等安全事故风险，基于流固耦合理论建立射孔弹的射流侵彻模型，综合考虑石油射孔弹壳体、炸药、药型罩、射孔枪和套管等结构，研究射流动能与壳体融化能量转化特征，得到不同因素影响下射孔弹剩余能量转化关系。结果表明：药型罩锥角、壳体厚度、炸药质量和类型等因素对射孔弹剩余能量有显著影响。药型罩锥角在40～70°之间越大，剩余能量占比越小；射孔弹壳体厚度在1～4 mm之间越厚，剩余能量占比越小；炸药质量在30～45 g之间越大，剩余能量占比越大；炸药质量相同时，三硝基甲苯(TNT)、六硝基芪(HNS)、黑索金(RDX)、奥克托今(HMX)等4种炸药中的HMX炸药剩余能量占比最小。     

振动对航空电连接器的影响分析

目的 根据提高电连接器可靠性的要求,研究振动对航空电连接器的影响.方法 针对研究所的现有设备,开展电连接器的振动测试.根据厂家数据使用Solid works对某型号电连接器进行参数化建模,通过COMSOL模态分析获得接触件的固有频率,使用ANSYS Workbench对接触件进行瞬态动力学分析和谐响应分析.在不同的振动...