高层级轮胎各层帘布裁断角度的计算方法

提出一种新的确定高层级轮胎内外各层帘布裁断角度的方法。根据各层帘布在成品胎内部的材料分布图和在成型机头上的材料分布图，计算该层所在的机头宽度，比较计算的机头宽度和实际的机头宽度，通过调整帘布裁断角度使两者近似相等。以此确定各层帘布的裁断角度，达到内外层帘线均匀伸张的目的。     

Surface grafting of polymers onto glass plate: Polymerization of vinyl monomers initiated by initiating groups introduced onto the surface

The surface grafting of polymers onto a glass plate surface was achieved by the polymerization of vinyl monomers initiated by initiating groups introduced onto the surface. Azo groups were introduced onto the glass plate surface by the reaction of 4,4′-azobis(4-cyanopentanoic acid) with isocyanate groups, which were introduced by the treatment with tolylene-2,4-diisocyanate. The radical polymerization of various vinyl monomers was initiated by azo groups introduced onto the glass plate surface and the corresponding polymers were grafted from the surface: The surface grafting of polymers was confirmed by IR spectra, and the contact angle of surface, with water. The contact angle of the glass plate increased by the grafting of hydrophobic polymers, but decreased by the grafting of hydrophilic polymers. The radical postpolymerization was successfully initiated by the pendant peroxycarbonate groups of grafted polymer on the surface to give branched polymer-grafted glass plate. The cationic polymerization of vinyl monomers was also successfully initiated by benzylium perchlorate groups introduced onto the glass plate surface and the corresponding polymers were grafted onto the surface. The contact angle of the glass plate surface obtained from the cationic polymerization of styrene was larger than that obtained from the radical polymerization. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2165–2172, 1997     

Characterizations of surfactant synthesized from Jatropha oil and its application in enhanced oil recovery

Surfactants are frequently used in chemical enhanced oil recovery (EOR) as it reduces the interfacial tension (IFT) to an ultra‐low value and also alter the wettability of oil‐wet rock, which are important mechanisms for EOR. However, most of the commercial surfactants used in chemical EOR are very expensive. In view of that an attempt has been made to synthesis an anionic surfactant from non‐edible Jatropha oil for its application in EOR. Synthesized surfactant was characterized by FTIR, NMR, dynamic light scattering, thermogravimeter analyser, FESEM, and EDX analysis. Thermal degradability study of the surfactant shows no significant loss till the conventional reservoir temperature. The ability of the surfactant for its use in chemical EOR has been tested by measuring its physicochemical properties, viz., reduction of surface tension, IFT and wettability alteration. The surfactant solution shows a surface tension value of 31.6 mN/m at its critical micelle concentration (CMC). An ultra‐low IFT of 0.0917 mN/m is obtained at CMC of surfactant solution, which is further reduced to 0.00108 mN/m at optimum salinity. The synthesized surfactant alters the oil‐wet quartz surface to water‐wet which favors enhanced recovery of oil. Flooding experiments were conducted with surfactant slugs with different concentrations. Encouraging results with additional recovery more than 25% of original oil in place above the conventional water flooding have been observed. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2731–2741, 2017     

Wettability between Fe-Al alloy and sintered MgO

In the current study, the wettability between Fe-Al alloy and sintered MgO substrate was investigated. The stable contact angle between the sintered MgO substrate and the liquid iron was approximately 134° at 1550 °C, hardly influenced by Al concentrations of 18 ppm and 370 ppm in the liquid iron. By changing hydrogen partial pressure from 0 vol% to 1 vol%, the oxygen partial pressure decreased. Meanwhile, the contact angle between the MgO substrate and the liquid iron with 370 ppm Al increased with the decrease of oxygen partial pressure. The oxygen partial pressure and contact angle were scarcely affected by increasing hydrogen partial pressure from 1 vol% to 5 vol%. In all cases with 370 ppm Al in the liquid iron, oxide layers were detected on the surface of iron samples. The oxidation of iron could be effectively prevented by increasing the hydrogen partial pressure. The MgO substrate was reduced to Mg vapor in the reducing atmosphere at a high temperature. Then the Mg vapor was dissolved into the iron even before iron melting. Under thermodynamic equilibrium condition, an oxide layer containing two components, i.e. MgO·Al₂O₃ phase and CaO-SiO₂-MgO-Al₂O₃ phase, was generated on the surface of the iron sample. Due to the different wettability between the iron and the two phases, MgO·Al₂O₃ phase was repelled, while the CaO-SiO₂-MgO-Al₂O₃ phase adhered to the inside area.     

胶凝材料颗粒组成对混凝土抗裂性能的影响

混凝土抗裂性能与其胶凝材料的堆积紧密程度有关。运用不同颗粒组成的水泥或粉煤灰调整胶凝材料的颗粒级配,可以拓宽颗粒分布范围,适当增加粗颗粒含量,提高混凝土抗裂性。用粉煤灰充当胶凝材料中的粗颗粒,不仅能改善混凝土抗裂性能,而且后期强度增进率较高,有利于提高耐久性;水泥企业应重视水泥颗粒级配的合理性,水泥中保持一定量的粗颗粒非常必要。试验表明,增加40μm以上颗粒含量就能起到改善混凝土抗裂性能的作用。     

Slow crack growth and hydrothermal aging stability of an alumina-toughened zirconia composite made from La2O3-doped 2Y-TZP

A very tough zirconia matrix is interesting to fabricate alumina-toughened zirconia (ATZ) and composites generally processed from 3Y-TZP do not exhibit very high toughness. The strategy of lowering the yttria content to increase toughness however is normally associated with an increased hydrothermal aging susceptibility. In this work, a 0.4 mol% La₂O₃ doped 2Y-TZP matrix was investigated to realize a 20 wt.% alumina toughened zirconia composite with a substantially high aging resistance. The higher transformation toughening in the composite shifted the V-K_I towards higher K_I values, while preserving the slope of the curve, resulting in a threshold K_I0 of 4.0 MPa m^1/2 and fracture toughness (K_IC) of 7.1 MPa m^1/2. These composites can offer a better compromise between aging and crack resistance than traditional 3Y-TZPs and plain ATZ composites without La₂O₃ doping.     

Silicate-based polymer-nanocomposite membranes for polymer electrolyte membrane fuel cells

Proton-exchange membrane fuel cells have emerged as a promising emission free technology to fulfill the existing power requirements of the 21st century. Nafion^® is the most widely accepted and commercialized membrane to date and possesses excellent electrochemical properties below 80 °C, under highly humidified conditions. However, a decrease in the proton conductivity of Nafion^® above 80 °C and lower humidity along with high membrane cost has prompted the development of new membranes and techniques. Addition of inorganic fillers, especially silicate-based nanomaterials, to the polymer membrane was utilized to partially overcome the aforementioned limitations. This is because of the lower cost, easy availability, high hydrophilicity and higher thermal stability of the inorganic silicates. Addition of silicates to the polymer membrane has also improved the mechanical, thermal and barrier properties, along with water uptake of the composite membranes, resulting in superior performance at higher temperature compared to that of the virgin membrane. However, the degrees of dispersion and interaction between the organic polymer and inorganic silicates play vital roles in improving the key properties of the membranes. Hence, different techniques and solvent media were used to improve the degrees of nanofiller dispersion and the physico-chemical properties of the membranes. This review focuses mainly on the techniques of silicate-based nanocomposite fabrication and the resulting impact on the membrane properties.     

内压作用下斜接弯管纵向半穿透裂纹应力强度因子研究

采用三维有限元技术,应用ANSYS对内压作用下含纵向半穿透裂纹斜接弯管的应力强度因子进行了系统的分析。建立了三维有限元裂纹模型,对裂纹前沿应力强度因子的影响因素进行了研究,分析了不同内压下无量纲参数裂纹相对深度a/t、裂纹相对形状b/a、管壁相对厚度Do/t对应力强度因子的影响。     

尿素高压管道支管座在连接管焊缝侧开裂原因分析及防范措施

介绍美荷型480kt/a尿素装置高压系统,高压管道支管座与接管(≤DN50)焊缝在熔合线上的开裂原因及在线处理情况,并对开裂原因进行分析,得出损坏的主要原因由应力腐蚀引起,针对腐蚀原因提出防范和整改措施。     

对石化设备不锈钢应力腐蚀开裂的认识与反思

根据石化装置不锈钢设备曾发生过应力腐蚀开裂的事例,总结与归纳出一些共性的东西,可供选材、设计、加工、维护、管理与检测时借鉴,以尽可能减少设备腐蚀开裂事故.