Vegetable fillers for electric stimuli responsive elastomers

Dielectric elastomer actuators (DEAs) have been studied widely in recent years for artificial muscle applications, but their implementation into production is limited due to high operating voltages required. The actuation behavior of dielectric elastomer under an applied electric field is predicted by Maxwell's pressure and thickness strain equations. According to these equations, the best electromechanical response is achieved when the relative permittivity is high and elastic modulus is low. The potential source for additives increasing the relative permittivity of rubbers can be vegetable powders that have much higher dielectric constant than common elastomers. In the present research, the dielectric and actuation properties of polyacrylate rubber (ACM) were studied after the addition of different vegetable‐based fillers such as potato starch, corn starch, garlic, and paprika. The results were compared to ACM filled with barium titanate. The compounds containing vegetable fillers showed higher relative dielectric permittivity at 1 Hz frequency than the compounds containing barium titanate due to higher interfacial polarization. The actuation studies showed that lower electric fields are required to generate certain actuation forces when the starches and garlic are used in the rubber instead of barium titanate. Therefore, the vegetable‐based fillers can be used to improve actuation performance of DEAs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45081.     

Polyhydroxyalkanoate‐based drug delivery systems

Microbial polyhydroxyalkanoates (PHAs) have been a subject of significant research interest in the past few decades. The recent development of novel functionalized PHAs has opened up new possibilities to combine the good biocompatibility of PHA‐based drug delivery systems to, for example, improve drug loading and release properties, targeting or imaging functionalities. This mini‐review presents some recent scientific developments in the preparation of functionalized PHAs, PHA–drug and PHA–protein conjugates, multifunctional PHA nanoparticles and micelles as well as biosynthetic PHA particles for drug delivery. These developments in combination with the generally excellent biocompatibility of PHA materials are expected to further expand the interest in PHA materials for drug delivery and other therapeutic applications. © 2016 Society of Chemical Industry     

NiO/Al_2O_3基催化剂的TPR特性研究

NiO/Al_2O_3基催化剂用于替代贵金属催化剂,被广泛应用于石油和石化领域生产过程的加氢、脱硫和脱氮。采用TPR方法,研究不同Ni含量NiO/Al_2O_3及不同载体的催化剂还原特性。结果表明,NiO/Al_2O_3催化剂在10%H_2-Ar气氛下,还原温度范围较宽,为(300~800)℃,其中,(500~600)℃还原速率最大;随着NiO含量的增加,起始还原温度降低,还原耗氢量按比例增加;以MgO为载体的NiO催化剂还原呈现双峰特征,以SiO2和TiO2为载体的NiO催化剂的初始还原温度比NiO/Al_2O_3催化剂降低(100~200)℃。     

航天紧固件用TC4钛合金棒材固溶时效后的组织与性能

对航天用紧固件TC4钛合金棒材进行固溶时效处理,对棒材不同位置进行显微组织观察、硬度和室温拉伸性能检测。结果表明:TC4钛合金棒材经固溶时效后表面至心部的组织与性能受冷却速度的影响呈现显著差异。固溶时效后的显微组织由稳定的等轴α相、弥散的马氏体α′相和亚稳定β相组成,试样端面上因冷却速度相差不大,次生α相的形态和含量没有明显差异;中部截面上边部至心部的次生α相含量逐渐增多,同时次生α相片层厚度逐渐增大并趋于等轴化。端面上不同位置显微硬度值没有明显差异,但中部截面上由边部至心部的显微硬度值呈总体降低趋势,且中部截面上边部的显微硬度值与端面相差不大。试样心部因固溶过程中冷却缓慢,整体试样的室温拉伸性能明显低于去除心部的试样。     

无动力处理方式在农村生活污水处理中的应用

论述了北方某镇采用无动力处理技术处理农村生活污水的方法,工艺流程为新型化粪池-人工湿地-氧化塘工艺。运行结果表明,工程出水中污染物日均浓度COD为35~55 mg/L、BOD5为10~20 mg/L、SS为5~18mg/L、氨氮为3~5 mg/L,均能达到《农田灌溉水质标准》(GB 5084-2005)中蔬菜a标准。处理后的出水用于周边农田灌溉,既治理了污染,又节约了资源,是绿色、低碳城镇建设的一个典范,非常适合北方乡镇新农村建设的生活污水处理和利用。     

C29重排谷甾烷在油源对比研究中的应用——以银额盆地查干凹陷为例

基于银额盆地查干凹陷巴音戈壁组一段、二段烃源岩岩性、古生物化石、热演化程度对比结果,首次提出C29重排谷甾烷不受烃源岩热演化程度影响,主要与烃源岩原始母质中植物的贡献有关的观点.C29重排谷甾烷在植物炭屑质量分数高的巴一段灰黑色、深灰色泥岩中含量高,在植物炭屑质量分数低的巴二段深灰色泥岩中含量低,可作为指示母质类型的地...     

静压法油罐计量系统在油库的应用

对静压法计量系统在油库中的应用做了说明,该系统运行稳定可靠,加强了罐内油品的管理及液面控制,可降低劳动强度,经济效益显,并从讲理原理、系统构成和计量精度等方面进行了详细的介绍。     

Effect of hot drawing on properties of wet‐spun poly(L,D‐lactide) copolymer multifilament fibers

Polylactide stereocopolymer multifilament fibers were prepared by wet spinning and subsequent hot drawing. The stereocopolymers were poly‐(L,D ‐lactide) [P(L,D )LA], L/D ratio 96/4, and poly‐(L,DL ‐lactide) [P(L,DL )LA], L/DL ratio 70/30. They were dissolved in dichloromethane and coagulated in a spin bath containing ethanol. The hot‐drawing temperature was 65°C. The draw ratios (DR) were upto 4.5 to the P(L,D )LA 96/4 filaments and upto 3 to the P(L,DL )LA 70/30 filaments. Wet spinning decreased crystallinities of both copolymers. Hot drawing increased the crystallinity of the P(L,D )LA 96/4 filament but not to the level of the original copolymer, whereas the as‐spun and the hot‐drawn P(L,DL )LA 70/30 filaments were amorphous. The filament diameter, tenacity, Young's modulus, and elongation at break were dependent on the DR. The maximum tenacity (285 MPa) and Young's modulus (2.0 GPa) were achieved with the P(L,D )LA 96/4 filament at the DR of 4.5. Respectively, the maximum tenacity of the hot‐drawn P(L,DL )LA 70/30 filament was 175 MPa and Young's modulus 1.3 GPa at the DR of 3. Hot drawing slowed down in vitro degradation rate of both stereocopolymer filaments. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010