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31.
Changxin Liu Jinliang Ding Anthony J. Toprac Tianyou Chai 《Knowledge and Information Systems》2014,41(2):401-421
A data-based adaptive online prediction model is proposed for plant-wide production indices based on support vector regression, a general method which we customized specifically to model very large data sets that are generated dynamically and periodically. The proposed model can update its parameters online according to the statistical properties of the training samples. Further, in order to improve the prediction precision, each sample is weighted with a dynamic penalty factor that considers the effect of each sample on the prediction model accuracy. Moreover, a customized procedure is introduced to handle large training sets. After having been convincingly evaluated on benchmark data, effectiveness and performance of our approach for plant-wide production indices is demonstrated using industrial data from an operating ore dressing plant over a range of scale in training data set size. The higher accuracy and shorter computation times than existing methods suggest that it may prove advantageous in actual application to dynamic production processes. 相似文献
32.
The swelling properties of different chitosan–poly(vinyl alcohol) (PVA) hydrogels were investigated as functions of the medium pH and salt concentration. The maximum swelling ability of the hydrogels was at a buffer pH of approximately 3, regardless of the PVA content in the hydrogels. The maximum mass of the swollen hydrogels was about 13 times that of their contracted counterparts. The cyclical swelling and contraction between pH 3 and pH 7 buffers and pH 3 and pH 3 buffers with salt confirmed the Donnan swelling mechanism of these hydrogels. The swelling mechanism was considered the transfer of water molecules driven by a concentration gradient. This was represented by a simplified mass‐balance model, which neglected the effect of the ionization reaction, for the initial swelling period. The effective mass‐transfer coefficient of water molecules during swelling, estimated with this model, gradually decreased with increasing PVA content in the hydrogels. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4665–4671, 2006 相似文献
33.
34.
用内循环无梯度反应器,在593~633K范围内考察了在乙苯/乙烯进行定向烷基化反应合成对二乙苯时,EA-8402分子筛催化剂的失活行为,建立了相应的失活动力学模型: -da/dt=0.3271exp(-12.94/T)P_(EB)~(0.02)P_(E(?))~(0.383)·α这一模型可作为该反应的宏观动力学模型的补充。由失活级数d=1,按Levenspiel判据推断:其失活机理应该是不受内扩散阻力控制的平行-连串失活。 相似文献
35.
Inhibitory effect of Cr(Ⅵ) on activities of soil enzymes 总被引:1,自引:0,他引:1
To evaluate the influence of various Cr(VI) concentrations (0.05, 0.25, 0.50, 1.00 and 2.00 g/kg) on the activity of soil
enzymes, the activities of catalase, polyphenol oxidase, dehydrogenase, alkaline phosphatase in soils were investigated in
the incubation experiment with a period of 35 d. The results indicate that all the tested Cr(VI) concentrations significantly
inhibit dehydrogenase activity by over 70% after 35 d. The activity of alkaline phosphatase is slightly inhibited during the
whole experiment except for on the day 7. Cr(VI) has no obvious effect on the activity of catalase in soil. On the contrary,
Cr(VI) stimulates the activity of polyphenol oxidase. The results suggest that dehydrogenase activity can be used as an indicator
for assessing the severity of chromium pollution.
Foundation item: Projects(2006AA06Z374, 2007AA021304) supported by the National High-Tech Research and Development Program of China; Project(2008SK2007)
supported by the Key Program of Science and Technology of Hunan Province, China 相似文献
36.
本文首先介绍了常用的植入方法并分析了优缺点,重点详细分析了基于扩展OpenC+-植入技术的实现方法。 相似文献
37.
Promotion of hydrogen permeation on metal-dispersed alumina membranes and its application to a membrane reactor for methane steam reforming 总被引:1,自引:0,他引:1
Maorong Chai Masato Machida Koichi Eguchi Hiromichi Arai 《Applied Catalysis A: General》1994,110(2):239-250
A mesoporous membrane for selective separation of hydrogen was prepared usingthe sol-gel method. Some metal salts such as RuCl3, Pd(NH3)4Cl2, RhCl3,, and H 2PtCl6, were added to the boehmite sol and coated on a porous alumina substrate before firing at 500°C. It was foundthat the permeability of hydrogen and the separation factor for a hydrogen-nitrogen gaseous mixture of these metaldispersed membranes exceeded the limitations of the Knudsen diffusion mechanism. Although the gas permeation through a neat alumina membrane is governed by the Knudsen diffusion, the metals dispersed in alumina membranes were effective in promoting hydrogen permeation. These metaldispersed alumina membranes were also used in a membrane reactor for methane steam reforming at low temperature. In the temperature range of 300 to 500°C, the membrane reactor attained a methane conversion twice as high as the equilibrium value of the packed bed catalytic reactor system as a result of the selective removal of hydrogen from the reaction system. 相似文献
38.
Aniello Leonardo Halak Basel Chai Peter Dhall Riddhi Mihalea Mircea Wilczynski Adrian 《International Journal of Information Security》2021,20(3):445-460
International Journal of Information Security - The complexity of today’s integrated circuit (IC) supply chain, organised in several tiers and including many companies located in different... 相似文献
39.
传统的沥青混合料冷再生技术有乳化沥青和泡沫沥青冷再生,本研究尝试采用所开发的溶剂沥青作为结合料对废旧沥青混合料进行冷再生,提出了试件的成型和养生方法,进行了配合比组成设计并采用热拌沥青混合料的标准对溶剂沥青冷再生混合料的性能进行评价.试验结果表明,溶剂沥青冷再生混合料的水稳定性能、高温稳定性能均满足我国热拌改性沥青混合料规范的性能要求,低温性能虽然不满足改性沥青混合料的要求,但能满足普通沥青混合料规范的性能要求. 相似文献
40.
Geetanjali Yadav Leonard A. Fabiano Lindsay Soh Julie Zimmerman Ramkrishna Sen Warren D. Seider 《American Institute of Chemical Engineers》2021,67(1):e16992
Algae-to-biodiesel processes are hindered by high costs and low energy return on investment.1,2. Herein, three foci in research improve algae-to-biodiesel processes by: (1) reducing high installation and energy costs in the CO2 sequestration, cultivation, and harvesting stages; (2) improving oil extraction and biodiesel generation; and (3) increasing utilization of the proteins in lipid-extracted biomass (e.g., for animal feed), as well as the omega-3 fatty acids for nutraceuticals and food supplements. A process is introduced that uses carbon dioxide to aid in all three of these foci. CO2 is used first in the form of microbubbles to lyse algae cell walls, releasing triglyceride oils. CO2 also aids with transesterification of these triglycerides using methanol. At low temperatures (353.15–368.15 K) and intermediate pressures (5–10 MMPa), carbon dioxide causes methanol to dissolve partially in the triglyceride phase and triglyceride to dissolve partially in the methanol phase, increasing the transesterification reaction rate. Due to the nondestructive nature of these processes, other metabolites can also be harvested providing improvements in both mass and economic efficiency with an overall sharp reduction in the modeled price of biodiesel. 相似文献