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71.
72.
V. Fernández‐Cegrí F. Raposo M.A. de la Rubia R. Borja 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2013,88(5):924-929
BACKGROUND: The effects of chemical and thermochemical pretreatments on the composition and anaerobic biodegradability of sunflower oil cake were studied to compare these pretreatments and to assess their effectiveness. Four reagents (lime, sodium hydroxide, sulphuric acid, and sodium bicarbonate) at concentrations of 25% (w/w) of dry weight of substrate and 20 g L?1 substrate concentration were used for the chemical pretreatment for 4 h. The same conditions were used for thermochemical pretreatment with heating at 75°C. After the pretreatments, the solid and liquid fractions were separated and subjected to biochemical methane potential tests. RESULTS: The methane yields of the solid fraction obtained with lime, sodium hydroxide, sulphuric acid and bicarbonate were 130±9, 54±4, 61±6 and 88±7 mL CH4 g‐1CODadded, respectively, and after thermochemical pretreatment were 26±2, 84±7, 74±7, and 77±6 mL CH4 g‐1CODadded, respectively. The methane yields for liquids were 152±13, 2±0, 0±0, 249±19 mL CH4 g‐1CODadded, for the chemical pre‐treatment, respectively, and after the thermochemical pretreatment were 273±13, 58±5, 0±0 and 145±12 mL CH4 g‐1CODadded, respectively. CONCLUSION: Only the solid fraction obtained after the chemical pretreatment with lime gave a methane yield higher (130 mL CH4 g‐1CODadded) than the obtained for the untreated solid material (114 mL CH4 g‐1CODadd). No thermochemical pretreatment enhanced the methane yield of the solid or liquid fractions of the untreated material. © 2012 Society of Chemical Industry 相似文献
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网络翻译系统中的格式信息流处理方法研究 总被引:5,自引:0,他引:5
随着国际互联网络技术的迅速发展 ,网络机器翻译技术应运而生 .但由于网上信息流格式具有多样性和多变性等特点 ,使得网络机器翻译技术面临新的困难和挑战 .以网络实时翻译系统为问题研究背景 ,对网络格式信息流处理方法进行了深入研究和探索 ,提出了基于动态知识获取和上下文相关分析的格式信息流处理方法 .该方法在使用机器翻译系统中对 HTML格式信息流处理取得了令人满意的效果 . 相似文献
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针对锦西厂合成氨装置一段炉在运行中出现的问题 ,认真分析了出现问题的原因 ,解决的办法 ,进行了技术改造 ,总结了技改后的运行情况 相似文献
77.
The engineering community has recognized the need for a higher retention rate in freshman engineering. If we are to increase the freshman retention rate, we need to better understand the characteristics of academic success for engineering students. One approach is to compare academic performance of engineering students to that of non‐engineering students. This study explores the differences in predicting academic success (defined as the first year GPA) for freshman engineering students compared to three non‐engineering student sectors (Pre‐Med, STEM, and non‐STEM disciplines) within a university. Academic success is predicted with pre‐college variables from the UCLA/CIRP survey using factor analysis and regression analysis. Except for the factor related to the high school GPA and rank, the predictors for each student sector were discipline specific. Predictors unique to the engineering sector included the factors related to quantitative skills (ACT Math and Science test scores and placement test scores) and confidence in quantitative skills. 相似文献
78.
针对武钢四烧的现有水质,结合工作实践,从清洗预膜、药剂选择和投加、控制微生物等方面,讨论了四烧循环冷却水的水质稳定处理。 相似文献
79.
Stephan Goebbels 《International Journal of Communication Systems》2010,23(5):569-595
Future mobile radio networks will aim at achieving ‘broadband access for all’, anywhere. The performance of a radio network vitally depends on the characteristics of the transmission path between the user terminal and the access point and the degree of network coverage. In urban areas, full broadband radio coverage is difficult to provide, causing a high variation in the link quality and making broadband services hard to realize. In rural regions, massive deployment costs prevent a full broadband coverage. Most of the time users have to settle for UMTS‐like wide area networks. For mobile users accessing services, such as video streaming, which require continuous broadband connectivity, it virtually results in intermittent network connectivity. The frequent disruption of the broadband link and its replacement with no or only low‐performance connections is a problem that should be addressed. This article introduces a new technique called Smart Caching (SC), which is able to mitigate variations in the network performance so that non‐real‐time and non‐interactive services' quality is substantially improved. SC supports pre‐fetching from a server and buffering data at the edge of the core network, in the so‐called Smart Cache. It transmits data with extremely high speed to be buffered in the mobile terminal when it is in the service range of an access point. This allows for the provisioning of data‐intensive services even in the case of patchy wireless broadband network coverage and intermittent connectivity. The performance of the SC service is evaluated with two different sophisticated queuing models, both based on the Markov arrival process. The benefit of the new technique is discussed and dimensioning issues are outlined. Furthermore, a comparison with legacy network setups is given. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
80.
在发动机台架试验时,对机油压力监测通常采用单一静态的机油压力阈值进行机油压力监测。发动机在高转速下发生机油泄漏或低转速时机油通道出现堵塞,台架监测到的机油压力不会立刻达到监测阈值,发动机运动副在短时间出现缺乏机油润滑或是冷却都会给发动机带来严重的机械损伤。采用机油压力动态监测,可涵盖不同工况下故障监测与预警。以发动机转速、负荷及机油温度构建机油压力二阶多项式数学模型,对3台样本发动机的预测值与测量值进行了线性回归分析。通过发动机台架试验,验证了稳态试验、瞬态试验及发生故障时机油压力动态监测的准确性,结果表明机油压力动态监测在发动机台架实验中比单一阈值监测能更加有效地保护发动机。 相似文献