Effects of hot water extraction pretreatment on physicochemical changes of Douglas fir

Hot water extraction (HWE) is an autocatalytic pretreatment that can be effectively integrated into most of the conversion technologies for extracting hemicelluloses from woody biomass. The objective of this study was to understand the influence of pretreatment factors on removal of hemicelluloses from Douglas fir chips. Compositional change in biomass was analyzed with ion chromatography and further confirmed with Fourier transform infrared spectroscopy (FT-IR). Highest hemicellulose extraction yield (HEY) was estimated to be 67.44% at the optimum reaction time (79 min) and temperature (180 °C) by using response surface methodology (RSM). Experimental results show that the HEY increased from 19.29 to 70.81% depending on the reaction time (30–120 min) and the temperature (140–180 °C). Effects of the severity factor (SF) on the mass removal and compositional changes were also evaluated. Hygroscopicity and thermal stability of wood were improved after HWE pretreatment. Colorimetric analysis showed that temperature has a greater influence on color of the wood chips during HWE pretreatment than dwell time. HWE pretreatment shows great potential for extracting hemicelluloses and altering physicochemical properties of wood in an integrated biorefinery for diversification of product portfolio.     

N2 explosive decompression pretreatment of biomass for lignocellulosic ethanol production

This paper presents a novel biomass pretreatment method that uses high pressured N₂ and temperature to break the hemicellulose and lignin seal around the cellulose macro fibrils in the cell walls of the lignocellulosic biomass in order to open up the biomass structure for more efficient enzymatic hydrolysis. In this method the biomass is exposed to a high pressure using N₂ gas, and temperature. Under pressure, cells of the lignocellulosic biomass are filled with a solution saturated with nitrogen. When the pressure is then suddenly released, the feedstock is exposed to an explosive decompression and the dissolved nitrogen is released from the solution. Sudden change in the volume breaks the cell walls and opens the biomass structure resulting in increased surface area of the substrate for enzymatic hydrolysis. No catalysts or chemicals were added in the process thereby, making it economically and environmentally attractive. In this research, a range of different pressures (1–60 bar) and temperatures (25–175 °C) were applied to barley straw to evaluate the efficiency of the pretreatment. The pretreatment was followed by enzymatic hydrolysis and fermentation. Resulting glucose and ethanol concentrations were measured and the yields were considered as an estimate for the most suitable set of pretreatment conditions. The results indicate that the highest glucose yield and hydrolysis efficiency were gained at 150 °C and 10–30 bars. The fermentation efficiency was lower at higher temperatures. Nonetheless, the highest ethanol yield was still gained at the same conditions.     

换向脉冲镀金对铍青铜镀厚金层产品存储能力的影响

为提高电镀厚金层的存储性能,采用优化镀层预处理工艺方法,利用换向脉冲电镀技术在铍青铜试件上制备镀厚金层,并研究不同预处理工艺对长时间存储条件下镀层结合力的影响规律;利用X-射线能谱仪研究了优化预处理工艺对存储1~5年后镀厚金层的成分变化规律的影响;利用扫描电子显微镜与能谱仪研究了存储1~5年后镀层与铜基体之间的扩散行为。研究结果表明,换向脉冲电镀厚金层储存5年后,镀铜作为镀金的预镀层,镀层结合力最为优异;换向脉冲电镀厚金层的金原子数分数高于99.9%,镀厚金层具有优异的存储性能,但是镀厚金层界面处存在1.0~1.5μm的相互扩散现象。     

燃煤电厂软土层地基预处理方案和施工探究

本文阐述了预处理的重要性,揭示了当前施工中存在的问题,并对软土层地基处理提出了具体的方案。     

测量数据的分析与处理软件设计

介绍了采用LabWindows/CVI软件平台开发离线测量数据分析处理软件的设计方法。软件实现了对数据的读取与预处理，波形的显示与调节，信号的参数测量以及对频谱、功率谱和谐波失真进行了分析，利用多线程技术实现了软件的多任务同步进行。实验结果表明软件的分析结果正确，界面友好，性能可靠。     

废旧毛涤黏混纺面料脱色预处理工艺研究

以废旧毛涤黏混纺面料为研究对象,首先对面料进行清洁与消毒,然后对其组分进行定性、定量分析,最后通过单因素法优化,得出最佳的溶胀工艺为:m_(废旧面料)∶m_(DMSO)=1∶10,溶胀时间40 min,溶胀温度90℃。在该工艺下对织物进行溶胀处理,得到织物的质量损失率为3.06%,K/S值为16.906。     

An overview of algae bioethanol production

Because of rapid growth in population and industrialization, worldwide ethanol demand is increasing continuously. The first‐generation and second‐generation biofuels are unable to meet the global demand of bioethanol production because of their primary value of food and feed. Therefore, algae are among the most potentially significant sources of sustainable biofuels in the future of renewable energy because of the accumulating high starch/cellulose and because they are widely distributed in nature. The focus of this paper is to review the production and recent advances in research and development in the algae bioethanol, including pretreatment, hydrolysis, and fermentation of algae biomass. Despite the many developments made in the recent years, commercialization of algal bioethanol remains challenging chiefly because of the techno‐economic constraints. Technological breakthroughs in all major aspects must be overcome before it can be a successfully large‐scale and commercialized product. Copyright © 2014 John Wiley & Sons, Ltd.     

金属涂装硅烷前处理技术的研究进展

评述了金属涂装硅烷前处理技术的研究进展,对其成膜与防腐机理、工艺方法以及硅烷产品的改性做了详细的介绍。新型硅烷锆盐复合产品能够显著提高纳米膜层的耐蚀性,硅烷产品与高泳透力电泳涂料配套使用能够保证涂层的性能,硅烷产品稳定性的提高使其在工业生产中得到广泛应用。