Optimization of the activity of CaO/Al2O3 catalyst for biodiesel production using response surface methodology

In this work the response surface methodology (RSM) in conjunction with the central composite design (CCD) were used to optimize the activity of CaO/Al₂O₃ solid catalysts for the production of biodiesel. In order to measure the catalyst activity, we used palm oil as a representative raw material for the conversion to biodiesel. The biodiesel production was carried out in a batch laboratory scale reactor. The results showed that both the calcination temperature and the amount of calcium oxide loaded on the support had significant positive effects on the biodiesel yield. The maximum basicity and biodiesel yield obtained were about 194 μmol/g and 94%, respectively. Overall, the catalyst showed high performance at moderate operating conditions and its activity was maintained after two cycles.     

利用遥测信道转发GPS定位数据的方案设计

将遥测和外测结合，利用遥测手段完成外弹道测量，是遥测系统的一种新的重要应用。在此，对利用我国现有空用遥测设备转发GPS定位数据作为外弹道测量辅助手段的可行性进行了分析，并详细介绍了一种具有实用价值的实现方案。     

NASICON-structured Na_(3.1)Zr_(1.95)Mg_(0.05)Si_2PO_(12) solid electrolyte for solid-state sodium batteries

Using stable inorganic solid electrolyte to replace organic liquid electrolyte could significantly reduce potential safety risks of rechargeable batteries. Na-superionic conductor(NASICON)-structured solid electrolyte is one of the most promising sodium solid electrolytes and can be employed in solid-state sodium batteries. In this work, a NASICONstructured solid electrolyte Na_(3.1)Zr_(1.95)Mg_(0.05)Si_2PO_(12) was synthesized through a facile solid-state reaction, yielding high sodium-ionic conductivity of 1.33×10~(-3) S·cm~(-1) at room temperature. The results indicate that Mg~(2+)is a suitable and economical substitution ion to replace Zr~(4+), and this synthesis route can be scaled up for powder preparation with low cost. In addition to electrolyte material preparation, solid-state batteries with Na_(3.1)Zr_(1.95)Mg_(0.05)Si_2PO_(12) as electrolyte were assembled. A specific capacity of 57.9 mAh·g~(-1) is maintained after 100 cycles under a current density of 0.5 C rate at room temperature. The favorable cycling performance of the solid-state battery suggests that Na_(3.1)Zr_(1.95)Mg_(0.05)Si_2PO_(12) is an ideal electrolyte candidate for solid-state sodium batteries.     

Numerical study on microstructured reactor with chaotic heat and mass transfer and its potential application for exothermic process

Design of microstructured reactors with thermal control function is investigated through numerical simulation. It consists of one middle channel for handling chemicals and two other channels attached to its top and bottom for cooling purpose. Three designs are examined. Reactor A uses simple straight channels. In reactor B, chaotic flow is applied to the middle channel, and in reactor C chaotic flow is applied to all the three channels. Results show that in comparison with the straight channel, the Nusselt number in current design is greatly improved through chaotic flow. Rapid mixing is also achieved. Potential application of the design for continuous exothermic process is analyzed. For reactor A, it is not workable as the temperature of the chemical solution continuously increases over the channel. In comparison, for both reactors B and C the temperature can be well controlled within the required range. As the coolant flow in reactor C is also chaotic, it provides a higher heat removal capacity.     

对撑支护形式在基坑工程中的应用研究

以御锦公馆基坑工程为例,根据该工程周边环境及地质状况,采用对撑支护结构体系进行支护,并对支护结构体系进行数值分析,通过监测数据与计算结果的对比,指出对撑支护形式能很好的控制变形,从而减少基坑开挖对周边环境的影响。     

Supporting browsing-specific information needs: Introducing the Citation-Sensitive In-Browser Summariser

Practitioners and researchers need to stay up-to-date with the latest advances in their fields, but the continual growth in the amount of literature available makes this task increasingly difficult. In this article, we describe the Citation-Sensitive In-Browser Summariser (CSIBS), a new research tool to help manage the literature browsing task. The design of CSIBS was based on a user requirements analysis which identified the information needs that biomedical researchers commonly encounter when browsing through academic literature. CSIBS supports researchers in their browsing tasks by presenting both a generic and a tailored preview about a citation at the point at which they encounter it. This information is aimed at helping the reader determine whether or not to invest the time in exploring the cited article further, thus alleviating information overload. Feedback from biomedical researchers indicates that CSIBS facilitates this relevance judgement task, and that the interface and previews are informative and easy to use.     

Multi-scale structure finite element analyses of damage behaviors of multi-axial warp-knitted composite materials subjected to quasi-static and high strain rate compressions

This paper reports a multi-scale structure finite element modeling scheme to analyze the damage behaviors of biaxial multi-layer warp-knitted composite materials subjected to quasi-static and high strain rate compressions. The multi-scale structure model includes: (1) a micro/meso/macro structure model with periodic boundary conditions for homogenizing the heterogeneous fiber/resin system into unit cells, and (2) a macroscopic rate-dependent plasticity model for the knitting composite materials combined with critical damage area failure theory, which accounts for the stiffness degradation and failure strength of the material. The finite element results from the model provide the locations of stress propagation, the stress distribution, and the progressive failure behavior within the biaxial multi-layer warp-knitted composite materials. The effects of the knitted yarns and the element number sensitivity of the macro-scale model have also been discussed.