Hydrogen and Oxygen Bubble Attachment to a Bitumen Drop

Air bubble – bitumen attachment is a critical step in the flotation of bitumen from mined oil sand. In this study, single bubble – bitumen drop attachment was observed directly using a novel experimental technique. Induction time is determined and used as an indication of bubble‐bitumen attachment potency for both hydrogen and oxygen bubbles. The attachment tests were conducted in deaerated municipal water (City of Edmonton tap water) at temperatures ranging from 22–50°C. Induction times measured for hydrogen bubble attachment were shorter than those for oxygen bubbles. Coalescence tests were also conducted in the absence of bitumen, and showed that hydrogen bubbles coalesced more rapidly than oxygen bubbles in both deaerated municipal water and clear (solids‐free) process water.     

钛矿渣电热法制取钛硅合金时直流电作用的实验研究

本文研究了实验条件下钛矿渣直流电硅热法制取钛硅合金时直流电对渣中TiO2还原贫化的作用．研究表明：直流电所特有的电解还原和金属液滴电泳沉降对渣中TiO2的还原及合金微粒的沉降均有促进作用外加直流电可使渣中TiO2贫化速度、合金中钛含量、合金收得率、钛回收率升高，合金中硅含量、残渣中TiO2含量降低．半工业性试验结果与此类似．     

低孔隙率胶凝材料的孔结构测定方法

本文用压汞法和氦比重仪法测定了低孔隙率胶凝材料的孔结构,结果表明氦孔隙率显著大于汞孔隙串。用两种方法测得的孔隙率与力学性能相关,得到完全不同的拟合参数。在低孔隙率胶凝材料中,大量闭合孔的存在使压汞法出现大的“损失孔隙”。因此,氦孔隙率可以作为低孔隙率胶凝材料的结构参数,而用压汞法可能会导致错误的结论。     

Electrically conductive composite of polypyrrole and liquid crystalline copoly(ester-amide)s

The modification of the mechanical properties of polypyrrole (PPY) by electrochemical preparation of conductive composite film from pyrrole (PY) and three kinds of liquid crystalline copoly(ester-amide)—PEA(H), PEA(C), PEA(O)—are presented. The electrical conductivity of the PEA(H)/PPY, PEA(C)/PPY, and PEA(O)/PPY composites are the same order of magnitude as PPY. The mechanical properties of the composite films are much better than that of pure PPY, and the composite films have good conductivity and thermostability. © 1994 John Wiley & Sons, Inc.     

Phase evolution and thermophysical properties of high-entropy RE2(Y0.2Yb0.2Nb0.2Ta0.2Ce0.2)2O7 oxides

Pursuing novel thermal barrier–coating materials with lower thermal conductivity and high-temperature stability can simultaneously improve the working efficiency and service temperature of a gas turbine. In this study, a series of high-entropy RE₂(Y_0.2Yb_0.2Nb_0.2Ta_0.2Ce_0.2)₂O₇ (RE = La, Nd, Sm, Gd, Dy, and Er) oxides were prepared though solid-state reaction. Through tuning the rare-earth cations, an order–disorder transition occurs from certain partially ordered weberite structure (C222₁) to disordered defective fluorite structure (Fm$\overline{3}$m). All the high-entropy RE₂(Y_0.2Yb_0.2Nb_0.2Ta_0.2Ce_0.2)₂O₇ oxides possess low thermal conductivity in the range of 0.91–1.34 W m⁻¹ K⁻¹ at room temperature, which can be attributed to increased lattice anharmonicity and disorder, resulting in additional phonon scattering. Herein, we proved that the incorporation of heterovalent cations at B-sites in high-entropy A₂B₂O₇ crystals is an effective strategy to reduce the thermal conductivity without compromising the decrease of oxygen vacancy. Moreover, the high-entropy RE₂(Y_0.2Yb_0.2Nb_0.2Ta_0.2Ce_0.2)₂O₇ oxides show the relatively higher thermal expansion coefficients of 10.3–10.7 × 10⁻⁶°C⁻¹ and excellent phase stability at elevated temperatures.     

国外塑料用着色剂及颜料市场的现状及趋势

综述了国外塑料着色剂和颜料的最新市场,尤其是美国和西德市场的最新动向。分别陈述了美国着色剂中镉的消费量和西德塑料工业中镉的消费量。指出了镉颜料具有色彩鲜艳、遮盖力强、分散性好、以及耐候、耐化学品和超热稳定性的优点。但是公众对重金属镉有引起肾病和致癌可能性的关注和耽忧与日俱增,因此在塑料制品中逐渐摒弃镉颜料及着色剂、使用镉的代用品,是一个值得注意的新动向。一些公司在摒弃镉的同时,正在研制符合环境要求的安全替代品。本文还对最新上市的十余种塑料着色剂及颜料新产品进行了报导。     

Reforming of methane and coalbed methane over nanocomposite Ni/ZrO2 catalyst

Nanocomposite Ni/ZrO₂-AN catalyst consisting of comparably sized Ni metal and ZrO₂ nanoparticles is studied in comparison with zirconia- and alumina-supported Ni catalysts (Ni/ZrO₂-CP and commercial Ni/Al₂O₃-C) for steam reforming of methane (SRM) and for combined steam and CO₂ reforming of methane (CSCRM). The reactions are performed under atmospheric pressure with stoichiometric amounts of H₂O and CH₄ or (H₂O + CO₂) and CH₄ at 1073 K. Under a wide range of methane space velocity (gas hourly space velocity of methane GHSV_CH4 = 12,000–96,000 ml/(h g_cat.), the nanocomposite Ni/ZrO₂-AN catalyst always shows higher activity and stability for both SRM and CSCRM reactions. The two supported Ni catalysts (Ni/ZrO₂-CP and Ni/Al₂O₃-C) exhibit fairly stable catalysis under low GHSV_CH4 but they are easily deactivated under high GHSV_CH4 and become completely inactive when they are reacted for ca.100 h at GHSV_CH4 = 48,000 ml/(h g_cat.). The CSCRM reaction is carried out with different H₂O/CO₂ ratios in the reaction feed while keeping the molar ratio (H₂O + CO₂)/CH₄ = 1.0, the results prove that the nanocomposite Ni/ZrO₂-AN catalyst can be highly promising in enabling a catalytic technology for the production of syngas with flexible H₂/CO ratios (ca. H₂/CO = 1.0–3.0) to meet the requirements of various downstream chemical syntheses.     

Study of thermally poled and corona charged poly(vinylidene fluoride) films

The effect of thermal poling and corona charging on the structure and characteristics of poly(vinylidene fluoride) films (PVDF) was investigated. The structure and chemical change of PVDF films with different polarizing treatments was examined using Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy, respectively. The characteristics including piezoelectric coefficients, ferroelectric hysteresis, and leakage current were measured. It was found that both polarized methods contribute to dramatic improvement on the piezoelectricity and ferroelectricity of PVDF films, while thermal poling leads to structure change with the generation of new carbon composition. The reason to cause leakage current was also analyzed. POLYM. ENG. SCI., 47:1344–1350, 2007. © 2007 Society of Plastics Engineers