Thermodynamic assessment of iron and the expansion behavior of porous ceramsite in pure mineral systems relating to solid waste components

Herein, Factsage software and sintering experiment were conducted to predict and correlate thermodynamic calculations of Fe in a synthetic solid waste and the expansion behavior of ceramsite. With the increase of Fe₂O₃ content, the liquid phase content and viscosity in the multi-component system gradually decreased and the melting temperature range became wider. This can match with the generation of the liquid phase with proper viscosity in the ceramsite and the full expansion properties. At 400–1000 °C, iron as a network former was tetrahedrally coordinated with oxygen to form Hercynite (Al₂FeO₄) phase; at 1180–1200 °C, iron as a network modifier dissolved into the silicate mineral structure to form the eutectic composition of Diopside (Ca₄Mg_3.62Fe_0.78Si_7.6O₂₄) and Ferrosolite (Si₁₆Mg_5.09Fe_10.66Ca_0.26O₄₈). The formation of iron-bearing silicate facilitated the generation of the viscous layer, so that the outer layer of the ceramsite exhibited sealing performance. Finally, a preferable porous ceramsite with compressive strength of 10.7 MPa and an apparent density of 708 kg/m³ was obtained. This study analyzes the effect of Fe₂O₃ on the expansion behavior of porous ceramsite and provides new insight into how to analyze different solid wastes to produce ceramsite in a predictable way.     

热塑性聚酰亚胺的热膨胀系数研究

利用静态热机械分析仪（TMA）测定了热塑性聚酰亚胺（TPI）注塑件的热膨胀系数α,考察了TPI的各向异性、尺寸稳定性以及添加不同填料对α的影响。结果表明：TPI存在着各向异性,且流向面的α最低。在正常的使用范围内,试样经历一个升降温循环后尺寸基本没发生变化。经消除热历史后,材料的α降低;类似地,热处理也能使。减小。在主链相同的TPI树脂中,加入玻纤、碳纤维等高强度、高热稳定性的填料有助于降低TPI的α。     

热缩圆套扩张工艺控制

探讨了管道防腐用热缩圆套的扩张工艺.在现有热缩材料的扩张方法基础上,对大口径热缩圆套的扩张,分析了预热温度、时间、扩张速度、辐照剂量等因素对扩张质量和效率的影响,摸索了一套最佳的工艺条件.     

讲授中有研究，学习中有运用

本文从化学反应工程分析的讲授体会出发,分析探讨了硕士学位课程的性质,讲授过程中教材的选取、内容和方法的把握,以及如何根据学生的具体情况,采用更有针对性的课堂讲解的议题。     

材料力学性能与液压胀接性能的关系

应用弹塑性力学的基本原理分析了材料的力学性能与液压胀接性能的关系,根据应力-应变曲线分析了胀接原理,给出了可实现胀接的必要条件,为选择合理的管子和管板材料提供理论依据。     

换热管在开槽管板中的液压胀接变形

根据圆筒的径向变形与弹性基础梁横向位移的微分方程具有相同形式的特点,将换热管的胀接变形比拟为弹性基础梁的变形,提出了管板开槽后管子胀接变形的分析方法。     

新型牙科铸钛专用包埋料的研制

研究了自制磷酸盐包埋料焙烧温度与膨胀率及膨胀系数之间,焙烧温度、固化时间与抗拉强度之间的关系,以及室温条件下一次包埋时包埋料与纯钛的界面反应情况.结果表明:包埋料的最大凝固膨胀率为0.1%,800℃的热膨胀率为0.46%,总膨胀率为0.56%,完全可以满足实际义齿铸造的要求.焙烧后抗拉强度在0.3～0.35MPa之间,正常固化24h后,包埋料的抗拉强度为2.35MPa,已经能够满足铸造过程的需要.Zr、P元素在纯钛中的扩散很小,可以忽略不计.金属元素Mg的扩散深度约为6μm,Al的扩散深度约为20μm,Si的扩散深度约为15μm,可以通过表面处理来保证铸件质量.     

Effects of seawater on AAR expansion of concrete

Recently, AAR was identified in submerged piles of some bridges in tidal waters. Microstructural examination detected chloroaluminate salts in some cracks. To clarify whether seawater had influenced the deterioration an experimental program was planned to examine the effects of sodium chloride on AAR under various curing conditions.Concrete prisms containing either of highly-reactive, slowly-reactive or nonreactive aggregate, and either low or high alkali contents, were stored in saltwater (representing seawater) or at 100% RH, at temperatures of 38, 60 and 80 °C, for expansion measurement over 600 days, after which the temperature for those stored in saltwater was lowered to 23 °C, to check its effect on further expansion, which could be attributed to precipitation of ettringite and/or Ca-chloroaluminate.The results indicate that the type of aggregate and concrete alkali content had the greatest effect on AAR expansion. Exposure to saltwater did not have any significant effect on the AAR expansion.     

胀管机用旋转门工作台的研制

介绍了胀管机用旋转门工作台的结构和工作原理。胀管机旋转门工作台应用于全自动液压胀管机,用来固定换热器工件。旋转门工作台上的挂装门设计成A和B两个工作面,挂装门在动力装置带动下可旋转180°,这样在挂装门A面进行胀管作业时,挂装门B面可同时进行工件的上、下料作业,挂装门A面胀管结束且挂装门B面上好待胀工件后,对挂装门A、B面进行180°的朝向互换旋转,进入下一工作循环。试验表明,能够有效地节省了胀管机上料、下料的工作时间,提高设备及人员的生产和工作效率,增强企业竞争力。