Effects of residual concentration of collector CTAC on flotation behavior of illite

ABSTRACT

In present study, illite flotation behavior with Cetyl Trimethyl Ammonium Chloride (CTAC) as the collector has been studied to investigate the effects of its residual concentration on froth stability and flotation. Results showed that, with increasing conditioning time, the residual concentration (frother concentration) and froth height decreased simultaneously, while the adsorbed amount (particle hydrophobicity) increased. Increasing CTAC conditioning time decreased the residual concentration in solutions, resulting in poor froth stability and flotation recovery at high pH; the adsorption rate of CTAC on illite surface was relatively high at higher pH due to strong electrostatic mechanism, making CTAC residual concentration decrease.     

顶空-气相色谱法及其在胶粘剂有机残留测定中的应用

顶空-气相色谱法作为一种符合"绿色分析化学"要求的分析手段,近年来引起人们广泛的研究兴趣。简要介绍了顶空-气相色谱技术及其在胶粘剂有机残留测定中的应用,并对其应用前景进行展望。     

“Growing Smarter Over Time”: An Emergence Model for Administrating a New Media Writing Studio

This article reports on efforts to create an administrative structure for learning and teaching multimodal composing that depends not on the leadership of a new media writing expert but on the collaboration of relative novices organized according to principles of emergent learning. Based on four years’ experience in a grant-funded program that supports new media composing in multiple disciplines, I report on the benefits of a bottom-up, emergent approach while raising questions about the long-term sustainability of such an approach. I conclude by describing efforts to create more top-down support for new media composing, while remaining committed to serving the teachers and students who are the real agents of change.     

Effect of residual stresses on crack behaviour in single edge bending specimens

Residual stresses due to manufacturing processes, such as welding, change the load bearing capacity of cracked components. The effects of residual stresses on crack behaviour in single edge bending specimens were investigated using Finite element analyses. Three parameters (J, Q and R) were used to study the crack behaviour. The J‐integral predicts the size scale over which large stresses and strains exist, the constraint parameter Q describes the crack‐tip constraint as a result of geometry, loading mode and crack depth and the constraint parameter R is used to describe the constraint resulting from residual stresses. To carry out a systematic investigation on the effect of residual stresses on the J‐integral and crack‐tip constraints, models under different combinations of residual stresses and external loads with different crack depths were analysed. It has been shown that the crack‐tip constraint R increased by tensile residual stresses around the crack‐tip. On the other hand, the constraint parameter R decreased and tended to zero at high external load levels.     

噻吩结构与O_2反应机理的理论研究

为研究煤自燃的反应机理,利用Gaussian 03程序,采用密度泛函理论(DFT)方法,在B3LYP/6-311G水平下研究煤结构中噻吩型有机硫与O2反应机理。由计算结果可知,反应物的初始连接方式有3种,其中Path 1的反应物经过过渡态TS1异构化为中间体IM1是无需克服势垒的放热过程,这说明煤中的噻吩结构无需从外界吸收热量,与氧气接触即可被氧化。此反应主要有6条反应路径,其中,Path 2是反应的主要反应路径,其速控步骤为过渡态TS6,需要克服的势垒为117.06 kJ/mol,其产物P2(C4H4O+SO)是反应的主要产物。     

谈公路隧道内轮廓断面的优化

根据公路隧道内轮廓的特点,从几何关系方面研究了隧道内轮廓形状快速确定的方法及过程,并借助于计算机程序设计,实现了对公路隧道内轮廓的快速、优化设计。     

Road bitumen's based on the vacuum residue of heavy oil and natural asphaltite: Part I – chemical composition

This work is devoted to studying the possibility of producing bitumen for road construction by using vacuum residue >420°C of heavy oil of the Ashal'chinskoe field in and natural asphaltite Spiridonovskoe field from Permian deposits in Tatarstan. The effect of natural asphaltite as a solid disperse phase element on the structural and group composition of the residual heavy oil product and its malacometrical qualities (penetration, extensibility, softening point, resistance to aging and adhesion) is revealed. The production of samples of compounded bitumen production was carried out by introducing the required amount of the shredded asphaltite to deasphaltizat vacuum residue of heavy oil and heating their mixture to 220°С with vigorous stirring. Changes in the composition and physical and chemical properties of deasphalting the residual heavy oil product, associated with the amount of injected asphaltite, showed the possibility of production of modified bitumen with better adhesion properties that correspond to road bitumen.     

Evaluation of Porous Structure of Cement Pastes Made with Residual Rice Husk Ash

In several countries, the residual RHA （rice husk ash） has been produced in rice processing industries or in thermoelectric plants that use rice husk to generate heat and/or electrical energy, usually without burning process control. This causes a reduction in the amorphous silica content of residual RHA, which distinguishes them from the RHA produced according to controlled burning process, which is totally amorphous and considered a highly reactive pozzolan. In this paper, the hydration products and the porous structure of binders paste were studied by replacing, in weight of 5%, 10% and 20% of Portland cement OPC （ordinary Portland cement）, by residual RHAs named A and B, which have high and low content of amorphous silica, respectively, using microstructure evaluation techniques as XRD （X-ray diffraction）, TG （thermogravimetric） tests and MIP （mercury intrusion porosimetry）. A reducing the size of the pores of the pastes was observed according to the increase of content replacement of RHA A and RHA B.     

《公共场所监测仪器直读数据与国家标准单位转换器》应用软件的设计与实现

本软件可为我单位公共场所管理人员提供监测现场的仪器直读数据与国家标准单位之间的转换功能。使我们的业务工作变得简便快捷、准确规范,极大地提高了工作效率,具有一定的社会效益。