滑框提模技术在桥梁高墩施工上的应用

结合工程实例,主要介绍了滑框提模施工技术在桥梁实心墩施工中的应用,指出滑框提模施工技术在桥梁高墩现浇混凝土中不仅机械化程度高、现场场地占用少、结构整体性强、安全作业有保障,而且还能较好的满足墩身外观及质量要求,是一项综合经济效益显著的施工技术。     

轴向压缩下圆形和多边形钢管混凝土柱的统一公式

目前,不同截面钢管混凝土(CFST)柱的轴向承载力采用不同的公式计算。研究人员和设计师试图在柱的设计中找到一个适用于不同截面(包括实心、空心、圆形和多边形截面)的统一公式,这一直是他们面临的一个挑战,事实上也是十分重要的问题。为满足现代的设计要求,结构在材料的使用、结构构件的拓扑学方面不断优化,上述问题应运而生。作者之前研究了圆形空心和实心CFST柱轴向承载力的统一公式,该文将其拓展到正多边形截面空心和实心CFST柱,将圆形截面作为多边形边数为1的特殊情况。最后,给出用于计算圆形或多边形截面实心和空心钢管混凝土柱轴向承载力的统一公式。此外,对空心圆形和方形钢管混凝土柱进行了试验。这些试验结果对有限的公开发表的文献进行了补充,也验证了该分析公式。     

Determination of trace amount of silver in water samples by flame atomic absorption after preconcentration by ZnO nano sorbent

A simple and fast method based on solid phase extraction (SPE) applying zinc oxide (ZnO) nanoparticles and atomic absorption spectrometry (AAS) was developed for the trace amount determination of silver (Ag) in aqueous samples. The method linearity was in the range of 14 to 700 ng mL^?1. The extraction efficiency of Ag was greater than 98% and limit of detection (LOD) was 4.2 ng mL^?1. The preconcentration factor was 200 and the relative standard deviation (RSD%) of the method was 3.7% (n = 6).     

Enhanced separation and extraction of cadmium and lead by a novel magnetite-immobilized-gelatin nano-sorbent

A novel magnetic nano-sorbent was synthesized by Schiff’s base formation via covalent bonding of gelatin to the surface of nano-magnetite-immobilized-3-aminopropyltrimethoxysilane (Nano-Fe₃O₄-Si-N=Gelatin). The structure was confirmed by the FT-IR, TGA, and SEM. The maximum capacity of Cd(II) and Pb(II) were identified as 440 and 400 µmol g^?1, respectively. The separation characteristics were evaluated in presence of various controlling factors. The sorption processes of Cd(II) and Pb(II) were found to follow the postulates of Langmuir, Brunauer-Emmer-Teller, and Dubinin Radushkevich isotherm models. The potential applications of Nano-Fe₃O₄-Si-N=Gelatin in water treatment of Cd(II) and Pb(II) were successfully accomplished using a micro-column technique.     

利用生活垃圾灰渣制备低硅含量玻璃及微晶玻璃

利用无机废弃资源制备高附加值玻璃及微晶玻璃制品,具有重要的社会及实际应用价值。通过低氧化硅含量的玻璃组成设计及微晶化处理,在生活垃圾焚烧灰渣利用率在90%的情况下,制备获得成型性能、机械性能与化学稳定性良好的微晶玻璃材料,并探讨了玻璃化学组成及热处理工艺对化学稳定性的影响。     

Improving dissolution kinetics of pharmaceuticals by fluidized bed impregnation of active pharmaceutical ingredients

Investigational drugs are increasingly becoming less soluble in aqueous media, thus, presenting real challenges during development. Previous work has successfully demonstrated the manufacturing of pharmaceuticals using fluidized bed (FB) impregnation of APIs onto porous carriers. This study demonstrates the usefulness of FB impregnation in formulating poorly soluble drugs. We show that dissolution of Fenofibrate is greatly improved by FB impregnation onto Neusilin^® (Fuji Health Science Inc, Burlington, NJ USA), a synthetic amorphous form of magnesium alumino‐metasilicate. We impregnate Neusilin^® for range of loadings and examine Fenofibrate's physical state. Dissolution of impregnated formulations is drug loading dependent and loadings below 40% show great improvement (decrease) in release time compared to physical blend. Release times are further improved by milling. We also examine feasibility of coimpregnating Fenofibrate with additives and observe stability (1.5 years) of the amorphous form of Fenofibrate inside Neusilin^®. This stabilization significantly improves Fenofibrate's dissolution kinetics, making our formulation comparable to one of the current market formulations, TriCor^® tablets (AbbVie Inc, North Chicago, IL USA). © 2016 American Institute of Chemical Engineers AIChE J, 62: 4201–4214, 2016     

Realization and control of multiple temperature zones in liquid‐containing gas–solid fluidized bed reactor

Fluidized bed reactors (FBRs) have been developed to establish multiple temperature zones for various industrial processes. To overcome the common weakness, this work proposed to spray liquid into bottom and upper zones, respectively, to realize multiple temperature zones FBR (MTZFBR). Temperature, pressure, and acoustic emission techniques were applied to fully characterize liquid interaction and hydrodynamics. Compared with the bottom liquid‐spraying approach, the upper liquid‐spraying approach showed higher temperature difference (ΔT) and better fluidization stability, thus was selected for further control studies. Effects of liquid flow rate, static bed height, and inlet gas temperature on MTZFBR were studied systematically. The results showed that increasing liquid evaporation behavior or decreasing liquid bridge behavior enhance ΔT and fluidization stability and vice versa. G–L–S fluidization pattern depended mostly on the liquid behaviors and fluidization stability, and thus the stabilized MTZFBR could be regarded as a coexisted mode of two distinctive G–L–S fluidization patterns. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1454–1466, 2016     

Analysis of particle cloud height dynamics in a stirred tank

Local and temporal variations of the particle cloud formed in a cylindrical mixing vessel were investigated experimentally. Different particle sizes (0.5, 1, and 2 mm) and volumetric concentration up to 20 vol % were evaluated at different impeller speeds. The time‐averaged cloud height was linear with impeller frequency and with volume concentration. Suspensions with larger particles had a lower average cloud height, while the standard deviation for the temporal cloud height variation was larger. Two strong periodic phenomena were identified to be dominating the particle cloud height variations. The frequencies were linear with impeller speed, resulting in dimensionless frequencies of S₁=0.02–0.03 and S₂=0.05–0.06. The frequencies were affected by neither the particle size nor the volumetric concentration. The amplitude showed no dependency on the particle size, but the S₂ amplitude significantly decreases and S₁ increases with increasing solid concentration. The results were compared to LES/discrete element method simulations and showed a fair agreement. © 2015 American Institute of Chemical Engineers AIChE J, 62: 338–348, 2016     

New vacancied and Dy3+-doped molybdates – Their structure,thermal stability,electrical and magnetic properties

Microcrystalline samples of new Cd_1–3xDy_2x⌷_xMoO₄ solid solution with limited homogeneity (0<x≤0.2222) and cationic vacancies (denoted as ⌷) were prepared by a high-temperature solid state reaction. The XRD data and SEM analysis showed that as-prepared ceramics crystallize in the tetragonal scheelite type symmetry (space group I4₁/a) with the crystallite size varying between ~2 and ~20 µm. A systematic change in lattice constants, a and c, as well as in lattice parameter ratio c/a with an increase of Dy content was observed. Dy-doped molybdates are paramagnets with the antiferromagnetic short-range interaction and spin-orbit coupling. Optical and electrical investigations proved Cd_1–3xDy_2x⌷_xMoO₄ solid solution to be in the insulating state of E_g>3 eV at room temperature and the thermally activated conduction of the Arrhenius-type above 350 K. Moreover, the I-V characteristics provided the evidence of symmetrical and non-linear behavior typical of charge carrier emission weakly induced by the temperature. Relative dielectric permittivity ε_r below 10 as well as loss tangent tanδ below 0.15 do not substantially depend both on the temperature in the range of 76–400 K and the frequency in the range of 5·10²–1·10⁶ Hz. These results are interpreted in the framework of the acceptor and donor vacancy centers.