Peracetic acid pretreatment of sugarcane bagasse for enzymatic hydrolysis: a continued work

Previous work has shown that the enzymatic hydrolysis of sugarcane bagasse could be greatly enhanced by peracetic acid (PAA) pretreatment. There are several factors affecting the enzymatic digestibility of the biomass, including lignin and hemicelluloses content, cellulose crystallinity, acetyl group content, accessible surface area and so on. The objective of this work is to analyze the mechanism of the enhancement of enzymatic digestibility caused by PAA pretreatment. Delignification resulted in an increase of the surface area and reduction of the irreversible absorption of cellulase, which helped to increase the enzymatic digestibility. The Fourier transform infrared (FTIR) spectrum showed that the absorption peaks of aromatic skeletal vibrations were weakened or disappeared after PAA pretreatment. However, the infrared crystallization index (N.O'KI) was increased. X‐ray diffraction (XRD) analysis indicated that the crystallinity of PAA‐treated samples was increased owing to the partial removal of amorphous lignin and hemicelluloses and probable physical change of cellulose. The effect of acetyl group content on enzymatic digestibility is negligible compared with the degree of delignification and crystallinity. The results indicate that enhancement of enzymatic digestibility of sugarcane bagasse by PAA pretreatment is achieved mainly by delignification and an increase in the surface area and exposure of cellulose fibers. Copyright © 2008 Society of Chemical Industry     

The influence of raw material characteristics on the industrial pelletizing process and pellet quality

Industrial pelletizing of sawdust was carried out as a designed experiment in the factors: sawdust moisture content, fractions of fresh pine, stored pine and spruce. The process parameters and response variables were energy consumption, pellet flow rate, pellet bulk density, durability and moisture content. The final data consisted of twelve industrial scale runs. Because of the many response variables, data evaluation was by principal component analysis of a 12 × 9 data matrix. The two principal component model showed a clustering of samples, with a good reproducibility of the center points. It also showed a positive correlation of energy consumption, bulk density and durability all negatively correlated to flow rate and moisture content. The stored pine was more related to high durability and bulk density. The role of the spruce fraction was unclear. The design matrix, augmented with the process parameters was a 12 × 6 matrix. Partial least squares regression showed excellent results for pellet moisture content and bulk density. The model for durability was promising. A 12 × 21 data matrix of fatty- and resin acid concentrations measured by GC–MS showed the differences between fresh and stored pine very clearly. The influence of the spruce fraction was less clear. However, the influence of the fatty- and resin acids on the pelletizing process could not be confirmed, indicating that other differences between fresh and stored pine sawdust have to be investigated. This work shows that it is possible to design the pelletizing process for moderate energy consumption and high pellet quality.     

声波时差测井在鄂尔多斯天然气勘探中的地质应用

本文应用声波时差测井资料判别划分地层压实异常段,并结合其它测井资料对盖层进行质量评估,寻找油气有利聚集带(段),为勘探提供有利区域和评价依据。     

F级高云母含量云母带的研制及应用

本文介绍了一种F级高云母含量云母带，它的主要特点是云母含量高达48％以上，具有良好的长时间耐电热老化性能，适用于高压电机主绝缘多胶模压工艺要求，该云母带的应用对提高电机绝缘水平和延长电机使用寿命具有重要意义。     

基于遗传神经网络的电站锅炉飞灰含碳量预测

针对锅炉飞灰含碳置影响因素复杂．实时测量难度大．精度低，提出了一种基于遗传神经网络的预测方法，并用于某电厂，结果表明，该方法是有效的。     

知识管理研究

通过对知识管理内容、过程、人和技术等方面的研究，提出今后知识管理研究在这些方面的重点。     

ZnO压敏陶瓷最佳掺杂含量的理论计算

从对电子薄膜材料研究中得到的最佳掺杂含量定量理论推广到ZnO陶瓷材料。该理论建立了电子薄膜材料的某一物理性能与晶体结构、制备方法和掺杂剂含量之间的联系，给出了一个能够拟合实验曲线的具有确定物理意义的抛物线方程。该方程的极值点确定了最佳掺杂含量与晶体结构和制备方法之间的定量关系，进而得到了一个掺杂最佳含量的表达式。系统地分析了ZnO压敏陶瓷的掺杂改性的实验结果，应用此表达式定量计算了ZnO压敏陶瓷的最佳掺杂含量，定量计算的结果与实验数据相符合。该理论也适用于其他薄膜材料最佳掺杂含量的理论计算。     

碘量法测铜中物质性质和分析操作

本文讨论了碘量法测定铜量中一些有关物质的特性,以及这些性质对分析条件和操作的要求。     

降低氧化铝生产中熟料折合比的探讨

在氧化铝生产过程中，熟料折合比是烧结法一项重要的综合性指标，本文通过对熟料折合比的定义、计算公式的剖析，分析了生产过程中影响熟料折合比的主要因素，对有效降低熟料折合比的措施进行了探讨。