Electroactive behavior assessment of poly(acrylic acid)‐graphene oxide composite hydrogel in the detection of cadmium

Super absorbent polymers of acrylic acid‐graphene oxide (PAA‐GO) were synthesized with different percentage of chemical neutralization (0, 10, and 20%) of the acrylic acid monomer before its polymerization. The influence of their swelling and adsorption/desorption capacity of cadmium ions in aqueous solutions were studied and revealed that the GO enables greater mechanical stability in the materials. The PAA hydrogels, with the same degrees of neutralization, were also prepared without GO to compare with the composites. Additionally, carbon paste electrodes (CPE) modified with the composites PAA‐GO were used to asses and compare their adsorption properties with cadmium(II). The anodic stripping voltammetry (ASV) peak, in the differential pulse voltammetry mode, for cadmium oxidation was found to be influenced by the presence of GO into the polymer, and also by their percentage of neutralization. The accumulation of cadmium(II) on the surface of the modified CPEs was performed under open‐circuit conditions taking an account the preconcentration time of the metal cation. The presence of GO enhances the electrical signal of the electrodes in short times of immersion in cadmium(II) solutions. This property contributed to get linear responses of the CPEs modified with the composites, which were influenced by their degrees of neutralization. The PAA‐GO 10N electrode with 10% of neutralization combined the influence of GO and the degree of neutralization in the same matrix, and also showed good performance in terms of its mechanical stability, it was chosen for preliminary studies on the selectivity of the electrode toward Zn(II) and Cu(II). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40846.     

Carbon nanotube–polyaniline composites

The last decade has seen a growing interest in hybrid electrically conducting nanocomposites. This article aims to provide a detailed overview of the present status of research in carbon nanotube–polyaniline (CNT/PANI) composites, from processing to structural and property evaluations. CNT/PANI are synthesized by electrochemical and chemical processing. When chemical methods are used, the main challenge is to obtain processable CNT/PANI in the emeraldine salt (ES) form composites. Stable dispersions of ES–CNT in organic media are prepared using the post doping method, inverse emulsion polymerization, or ex situ polymerizations. On the contrary, stable water dispersions of CNT/ES are prepared using hydrophilization of a preformed CNT/ES composite, direct synthesis of micelle–CNT hybrid templates, interfacial polymerization, covalent functionalization of CNT with a water soluble polymer, or using electrostatic interactions between two oppositely charged ES and CNT aqueous colloids. Moreover, the strategies for the synthesis of ternary CNT/PANI composites incorporating noble metal nanoparticles, metal oxide, or graphene sheets are also presented and analyzed in depth. Finally, we give a review of potential applications, including chemical sensors, capacitors, fuel cells and electronic devices.     

一种火腿肠用膏状香精的制备

结合香精调配技术和美拉德反应,通过单因素考察及正交试验,优化原料配比、工艺条件等各种影响因素,制备一种肉香浓郁、留香持久且稳定性好的火腿肠用膏状香精。研究结果表明,美拉德反应的最佳物料配比为：葡萄糖2．5g,DL-蛋氨酸1．5g,L-半胱氨酸1．0g;最佳工艺条件为：反应时间90min,反应温度103℃。     

Fabrication of apatite-type lanthanum silicate films and anode supported solid oxide fuel cells using nano-sized printable paste

Apatite-type lanthanum silicate based films have attracted significant interests to use as an electrolyte of solid oxide fuel cells (SOFCs) working at intermediate temperature. We have prepared Mg doped lanthanum silicate (MDLS) films on NiO–MDLS cermet substrates by spin coating and sintering of nano-sized printable paste made by beads milling. Changes in crystal structure and microstructure of the paste films with the sintering temperature have been investigated to show that porous network structure with a grain growth evolves up to 1300 °C, whereas densification occurred above 1400 °C. Anode supported SOFCs using the pasted MDLS films were successfully fabricated: an open circuit voltage of 0.91 V and a maximum power density of 150 mW cm⁻² measured at 800 °C were obtained with the electrolyte film sintered at 1500 °C.     

水泥保水性试验方法的研究与探讨

通过检测水泥泌水率的试验方法,从而研究水泥的保水性。研究结果表明:(1)无论是水泥净浆法或者水泥砂浆法都可以检测水泥的保水性,同时可以不考虑水泥的组成与结构;(2)试验应该严格按照标准进行,否则不同的称样量、水灰比、流动度等都会影响到水泥的保水性,也使得在比较水泥保水性时产生较大的误差;(3)利用泌水率来检测水泥保水性的灵敏度较好,可以简便快捷监控水泥的和易性,但如要详细分析水泥保水性的变化需要了解更多水泥方面的信息。     

针刺耐火纤维用膏体表面润滑剂的研制简

介绍了针刺耐火纤维用膏体表面润滑剂的研制过程,得到了用柴油/甘油混合溶剂与十八伯胺醋酸盐制作针刺耐火纤维用膏体表面润滑剂的结论。各物料的具体配比为柴油：甘油：十八伯胺醋酸盐=7.5~15∶67.5~60∶25（重量比）。其制作过程可以用十八伯胺和醋酸在柴油中合成后加入甘油调制,也可直接用十八伯胺醋酸盐按比例直接加热配制。     

生产湿法磷酸副产白石膏新技术

针对传统二水法磷酸副产的磷石膏杂质含量高、色泽差、资源化利用率低的问题,发明了湿法磷酸副产白石膏技术,所产的白石膏杂质含量低,可全部资源化利用。以我国目前湿法磷酸年产量计,年可产出白石膏5 000万t,市值达数百亿元,经济与社会效益好。     

抛光膏中磨料的解析

利用SEM，EDS分析了抛光膏中磨料的形状，尺寸和成分。结果表明，进口抛光膏中采有的磨料是直径为2－5μm的柱状氧化铝。     

Survival and inhibition of Staphylococcus aureus in commercial and hydrated tahini using acetic and citric acids

Tahini (sesame paste) is a low-moisture ready-to-eat food that has been linked to foodborne outbreaks and recalls. The objectives of this study were to investigate the behavior of Staphylococcus aureus in commercial and hydrated tahini at 10, 21 and 37 °C and to inhibit S. aureus in these products by 0.1, 0.3 and 0.5% acetic or citric acid. S. aureus was able to survive in commercial tahini with reductions of 3.3, 1.6 and 0.7 log₁₀ CFU/g at 37, 21 and 10 °C, respectively; while it grew in hydrated tahini with an increase of 3.9, 3.0 and 1.8 log₁₀ CFU/ml at 37, 21 and 10 °C, respectively, by 28d. Citric or acetic acid at ≤ 0.5% reduced S. aureus in commercial tahini by ≤ 2.3 log₁₀ CFU/ml by 28d compared to control at all of the tested temperatures. However, acetic and citric acid were more inhibitory at 37 and 10 °C, respectively. In hydrated tahini, viable S. aureus cells were not detected in the presence of 0.5 or 0.3% acetic acid after 7 and 14d, respectively, at both 21 and 37 °C; and after 14 and 28d, respectively at 10 °C. Acetic acid at 0.1% also reduced S. aureus numbers to undetectable levels after 14 and 28d at 21 and 37 °C, respectively. S. aureus cells were also not detected in the presence of 0.5% citric acid by 21d at all of the tested temperatures, or 0.1 and 0.3% citric acid by 28 and 21d, respectively at 21 °C. Acetic and citric acids could be used in tahini or tahini-based products to reduce the potential risk associated with S. aureus.     

Influence of clays on the rheology of cement pastes

The fresh state of concrete is becoming increasingly important in furthering the types of applications of today's construction world. Processing techniques have resulted in technologies such as self-consolidating concrete and depend on the microstructural changes that take place during and immediately after mixing and placing. These changes to the microstructure reflect the flocculation behavior between the particles in suspension. The ability to modify this behavior allows control over the balance among flowability and shape-stability of concrete. This study investigates how clay admixtures affect the microstructure of cement pastes from a rheological stand point. Shear and compressive rheology techniques are used to measure how the solids volume fraction of suspensions with different admixtures evolves with stress. Based on these relationships, the effectiveness of clays on the balance between flowability and shape-stability is measured. Results are consistent with green strength tests performed on concrete mixes derived from the cement paste mixes.