Ordinary Portland Cement composition for the optimization of the synergies of supplementary cementitious materials of ternary binders in hydration processes

The synergistic effects of using several supplementary cementitious materials (SCMs), such as Blast Furnace Slags plus Limestone Filler or Fly Ashes, depend on the OPC composition. When using an OPC which is poor in C₃A and alkalis in ternary formulations, a similar initial strength gain to that of a plain OPC is detected and at longer hydration ages, the formation of monocarboaluminate, hemicarbonate and hydrotalcite instead of monosulphate can be seen. If an OPC with a higher C₃A content and alkalis is used with SCMs, the higher availability of Al causes the early formation of monocarboaluminate and a lower initial strength gain. At longer hydration times, in ternary blends with both OPCs, the mechanical strengths are higher and the C-S-H gels formed are richer in Al and poorer in C/S ratio with a subsequent lowering of the alkali content in the pore solution when compared to that in plain OPC.     

Corrosion and Cavitation Erosion Behaviours of Cast Nickel Aluminium Bronze in 3.5% NaCl Solution with Different Sulphide Concentrations

The effect of sulphide(Na_2S) concentration(SC) on the corrosion and cavitation erosion behaviours of a cast nickel aluminium bronze(NAB) in 3.5% NaCl solution is investigated in this study.The results show that when the SC exceeds 50 ppm,the hydrogen evolution reaction dominates the cathodic process,and a limiting current region appears in the anodic branch of the polarisation curve due to the formation of a copper sulphide film,which is a diffusion-controlled process.After longterm immersion,the increased mass loss rate of NAB with the sulphide additions of 20 and 50 ppm is attributed to the less protective films,which contains a mixture of copper oxides and sulphides.Moreover,NAB undergoes severe localised corrosion(selective phase corrosion,SPC) at the β' phases and eutectoid microstructure α+κ_Ⅲ.By comparison,NAB undergoes general corrosion and a copper sulphide film is formed in 100 and 200 ppm sulphide solutions.Cavitation erosion greatly increases the corrosion rate of NAB in all solutions and causes a negative potential shift in 3.5% NaCl solution due to the film destruction.However,a positive potential shift occurs in the solutions with SC higher than 50 ppm due to the accelerated mass transfer of the cathodic process.The cavitation erosion mass loss rate of NAB increases with the increase of SC.The occurrence of severe SPC decreases the phase boundary cohesion and causes brittle fracture under the cavitation impact.The corrosion-enhanced erosion is the most predominant factor for the cavitation erosion damage when the SC exceeds 50 ppm.     

协同技术——让·普鲁维工作室关于装配式技术及工业化建造的探索 、发展与思考

本文以让·普鲁维工作室于第九届国际现代建筑大会所展示的Maison AIBa原型为切入点,全面回溯二战后让·普鲁维及其工作室以协同思维作为设计指导思想,在装配式技术及工业化建造领域的探索,以及该工作室力图将设计作为一种实验方法的尝试.在此基础上,作者进一步将让·普鲁维工作室的核心思想置于技术史与工程史视野范畴,意图探讨其中蕴涵的科学性和思辨性.     

建成环境与交通需求管理的协同效应研究展望

作为促进绿色出行的重要举措,已 有诸多研究分析建成环境或交通需求管理 对出行行为的影响,但大多数忽视了两者之 间的协同作用。准确分析建成环境、交通需 求管理对出行行为的影响机制,以及其协同 效应,能够为促进我国大城市绿色出行、贯 彻绿色发展理念提供理论支撑和精准施策 依据。本文基于当前研究现状,对建成环境 与出行行为、交通需求管理与出行行为的影 响,以及建成环境和交通需求管理的协同作 用研究进行了总结,并结合我国大城市建成 环境和居民出行特征对学术研究热点问题 进行展望。     

Transferring human grasping synergies to a robot

In this paper, a system for transferring human grasping skills to a robot is presented. In order to reduce the dimensionality of the grasp postures, we extracted three synergies from data on human grasping experiments and trained a neural network with the features of the objects and the coefficients of the synergies. Then, the trained neural network was employed to control robot grasping via an individually optimized mapping between the human hand and the robot hand. As force control was unavailable on our robot hand, we designed a simple strategy for the robot to grasp and hold the objects by exploiting tactile feedback at the fingers. Experimental results demonstrated that the system can generalize the transferred skills to grasp new objects.     

中国联通有线宽带和无线宽带协同发展策略研究

经过近几年电信行业的快速发展,我国已经成为全球第二大互联网市场,不仅有线宽带发展已经进入高峰期,且去年发放3G牌照后,中国移动通信市场也迎来了大发展。在此背景下,本文结合国外运营商有线宽带和无线宽带协同发展的案例研究,给出中国联通有线宽带和无线宽带协同发展的建议。     

稠油增效泵的研制及在河南油田的应用

稠油增效泵应用于稠油蒸汽吞吐水平井、大斜度井的举升.上下柱塞连接方式为活动接头,在受到较大扭矩时可产生旋转,分解掉作用的扭矩,避免了柱塞脱扣.设计有强制关闭固定阀,缓解了关闭滞后.对偏心固定阀采用弹簧进行扶正,阀的开启和关闭受井斜角的影响小.文中详细介绍了稠油增效泵的结构组成、工作原理、结构特点及现场应用情况.截止到2...     

Core business concentration vs. corporate diversification in the US electric utility industry: Synergy and deregulation effects

Many economists such as Wilson (2002) [Wilson, R., 2002. Architecture of power market, Econometrica, 70, 1299–1340] have considered that there are similarities between electricity and gas services in the US electric utility industry. Hence, they expect a synergy effect between them. However, the two businesses do not have technology similarities at the level that the gas service produces a synergy effect with electricity. To examine whether there is a synergy effect of corporate diversification in the industry, we compare electricity-specialized firms with diversified utility firms in terms of their financial performance and corporate value. The comparison indicates that core business concentration is more effective for electric utility firms than corporate diversification under the current US deregulation policy.     

Do males and females think in the same way? An empirical investigation on the gender differences in Web advertising evaluation

Informativeness and entertainment are regarded as two types of advertising value that can influence consumers’ attitudes toward Web advertising. Despite of many studies on these two factors, there are two research gaps in extant literature. First, the effects of informativeness and entertainment on attitude are considered separately, yet their interaction effect is neglected. Second, the role of individual characteristics (e.g., gender) in the advertising evaluation process is far from clear. To address these two issues, a laboratory experiment was conducted to investigate the interaction effect between informativeness and entertainment, and also the moderating role of gender. The results indicate that informativeness can help form a more positive attitude for males than for females, and entertainment can lead to a more positive attitude for females than for males. It is also found that there is a three-way interaction among informativeness, entertainment, and gender. More specifically, the interaction effect between informativeness and entertainment is significant for females, but insignificant for males. Results, research contributions, and limitations are discussed, and implications for future studies are suggested.     

Surface nano-aggregation and photocatalytic activity of TiO2 on H-type activated carbons

The main objective of this work is to detect any associative or synergistic effects between TiO₂ and activated carbon in 4-chlorophenol photodegradation. Different activated carbons (AC) were prepared from Tabebuia pentaphyla wood by means of physical activation with CO₂ or by extensive carbonization under N₂ flow at temperatures from 450 °C up to 1000 °C during 1 h. Results indicate a clear correlation between photocatalytic activities of titania with texture and surface chemistry of AC. Kinetic results of 4-chlorophenol photodegradation indicate that for most of mixed TiO₂ and AC solids a synergistic effect between both solids is observed. Surface nano-aggregation of TiO₂ on AC was observed by scanning electronic microscopy and dispersion of TiO₂ nanoparticles was improved as a function of more basic surface pH of AC. In conclusion, an increase of electronic density in carbon support clearly introduces an enhancement in titania's photoactivity for 4CP photodegradation. This beneficial effect indicates that it is possible to obtain clean water in a much shorter period of time by employing some selected AC in conjunction with TiO₂.