Extrusion coating performances of iPP/LDPE blends

The performance of iPP/LDPE blends in an extrusion coating process was investigated in the terms of coating width and draw‐down ability. It is well known that iPP alone is not proper because of lower draw‐down ability with severe draw resonance in elongational flow. To obtain higher draw‐down ability, iPP was blended with LDPE. Additionally, iPPs having different molecular weight distribution (MWD) were used in this study to find out the effect of MWD of iPP on neck‐in and draw‐down ability. It was observed that iPP/LDPE blend with narrower MWD exhibits narrower coating width and higher draw‐down ability. Neck‐in and draw‐down ability were correlated with shear and elongational properties obtained by several rheological measurements. From this study, the major rheological parameters affecting extrusion performance in iPP/LDPE blends could be assessed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Misconceptions about real-time databases

Increasingly, computer systems-even general purpose systems-are requiring real time support, so it's not surprising to hear more about real time databases. Unfortunately, there are many misconceptions about the real time aspects of databases. Mainstream database users who don't have any experience with real time systems mistakenly think they are synonymous with speed. Others argue that conventional database technology can be used in real time applications. To help bring order to the current state of confusion, the authors review nine common misconceptions about real time databases. They also describe key research areas that need to be addressed to encourage increased activity in this challenging area     

Games to Create Awareness and Design Policies for Transboundary Cooperation in River Basins: Lessons from the Shariva Game of the Mekong River Commission

International river basins cover a vast majority of the land surface, international cooperation is therefore important for the proper management, and to assure equitable and effective use in the basins. Key elements to improve international cooperation are common understanding of the issues in the basin, understanding upstream-downstream impacts and sharing a common vision for the future. This article focuses on the role of games in international basin cooperation to create awareness and to support policy development. The paper analysed the effects of the game in creating awareness and upgrading knowledge amongst water and related professionals and in designing procedures for cooperation in transboundary river basins. This was analysed during the implementation of the game with 28 participants from the four Lower Mekong countries. The impact on creating awareness and upgrading knowledge was evaluated through the use of questionnaires and pre- and post evaluation questions and for the design of policies, a SWOT analysis was used to evaluate the usefulness of the policies and frameworks as well as to identify possible improvements to the framework. The game implementation proved to be an appropriate tool to provide a practical way for stakeholders to become acquainted with the administrative and technical tools available in the Lower Mekong Basin. Pre- and post test shows that participants gained substantial knowledge on transboundary cooperation and use of tools. The game was part of a longer training programme addressing all the issues, however, the participants gained additional knowledge and insight by playing the game, well above what they had learned during the earlier training workshops. Playing the game proved an important aspect in training and education of such complex systems. The study also shows the role games can play in policy analysis, in particular the way the game provided insight in the design of the policy and the development of procedures, and their function to review and update policies and procedures. A number of recommendations have been made to strengthen the role in both training and education as well as in design of procedures.     

On the robust LQG control of TCSC for damping power systemoscillations

This paper deals with the application of the LQG (linear quadratic Gaussian) technique to the design of a robust TCSC (thyristor controlled series compensator) controller for power system oscillation damping enhancement. This paper discusses each process involved in the LQG design technique applied to the TCSC damping controller design. This paper also discusses the pitfalls in applying the LTR (loop transfer recovery) technique to reserve the robustness of the LQG damping controller. The robustness of the designed controller is verified by nonlinear power system simulation, which shows that the controller is effective for damping power system oscillations     

Nanocomposite piezoelectric films of P(VDF‐TrFE)/LiNbO3

Piezoelectric films were prepared by incorporation of lithium niobate (LiNbO₃) nanoparticles into copolymer of vinylidene difluoride and trifluoroethylene. Nanoparticles of LiNbO₃ with ferroelectric phase were successfully synthesized and dispersed homogenously by ultrasonication in the copolymer matrix without any surfactant or surface functionalization. The nanocomposites were fully characterized by electronic microscopy, X‐ray diffraction, differential scanning calorimetry, dynamical mechanical analysis, and piezometer. Surprisingly, the copolymer matrix crystallinity and morphology were not affected by the incorporation of nanoparticles. Therefore the nanocomposites remained good mechanicals properties and high ferroelectricity coupled to nonlinear optical activity thanks to the noncentro symmetric space group of lithium niobate. This could be a novel approach to develop new multifunctional materials. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

A neural/fuzzy optimal process model for robotic part assembly

A process model for part assembly task, using robotic manipulators, is introduced. A neural network control strategy, based on measured force and moment data, for avoiding jamming during part insertion is presented. Fuzzy set theory, well-suited to the management of uncertainty, is introduced to address the uncertainty problem associated with the part insertion procedure. The degree of uncertainty associated with the part insertion is used as an optimality criterion for a specific task execution. The proposed technique is applicable to a wide range of robotic tasks including part mating with various shaped parts.     

屏蔽式主泵飞轮方案论证及转子轴系动态性能敏感性分析

为保证核电主泵满足反应堆停堆和断电事故后惰转时间的要求,对屏蔽式主泵机组的转动惯量要求、飞轮配重方案以及主泵转子轴系的动态性能进行分析,给出了飞轮方案,并进行轴承水膜刚度对转子轴系动态性能影响的敏感性分析.     

The fabrication of efficiency-improved W-series interconnect type of module by balancing the performance of single cells

Large dye-sensitized solar cells (DSCs) are usually fabricated as module types instead of single cell types, because the overall efficiency of an area-expanded single DSC is decreased by its large surface resistances and low fill factor (FF). The general DSC module designs are the parallel grid, series interconnect, and series monolithic types. The W-series interconnect type of module has some advantages, such as its easy fabrication and simple structure. Moreover, it also avoids the reduction in the FF. However, it has an efficiency imbalance between the single cells, because of the discrepancy in their luminous intensity. Therefore, the fabrication of the W-series interconnect type of module will be cost-effective only if the problem of its efficiency imbalance is solved. In this study, the thickness of the Pt layer, which has a very high reflection rate, and that of the electrolyte layer are minimized and the transmitted light is reflected by a metallic thin film in order to increase the number of photons absorbed by the dye molecules in the module. As a result, the performance of the efficiency-balanced W-module is improved by approximately 1% as compared to that of the conventional module.     

A benzothiazole-based semisquarylium dye suitable for highly selective Hg sensing in aqueous media

A novel semisquarylium dye was synthesized by the reaction between 3,4-dibutoxy-3-cyclobutene-1,2-dione and a benzothiazolium salt and its metal ion sensing properties were investigated using absorption and emission spectroscopy. These misquarylium exhibited high selectivity for Hg²⁺ ions, as compared with Ca²⁺, Pb²⁺, Al³⁺, Ce²⁺, Ba²⁺, Ni²⁺, Cd²⁺, Zn²⁺ and Mg²⁺ ions in DMSO/H₂O (9:1, v/v), which was attributed to the formation of a 2:1 BSQ:Hg²⁺ coordination complex, the formation of which was supported by the calculated geometry of the complex.