35 research outputs found

    Application Study on the Dynamic Programming Algorithm for Energy Management of Plug-in Hybrid Electric Vehicles

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    To explore the problems associated with applying dynamic programming (DP) in the energy management strategies of plug-in hybrid electric vehicles (PHEVs), a plug-in hybrid bus powertrain is introduced and its dynamic control model is constructed. The numerical issues, including the discretization resolution of the relevant variables and the boundary issue of their feasible regions, were considered when implementing DP to solve the optimal control problem of PHEVs. The tradeoff between the optimization accuracy when using the DP algorithm and the computational burden was systematically investigated. As a result of overcoming the numerical issues, the DP-based approach has the potential to improve the fuel-savings potential of PHEVs. The results from comparing the DP-based strategy and the traditional control strategy indicate that there is an approximately 20% improvement in fuel economy

    Bruise Patterns of Fresh Market Apples Caused by Fruit-to-Fruit Impact

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    Comprehensive understanding of bruise damage caused by apple-to-apple impacts is beneficial to design a low-impact fruit capturing mechanism for mass (shake-and-catch) harvesting, as well as to design other fruit handling devices. This study quantified the bruising severity in ‘Jazz’ apples induced by different levels of impact upon various fruit surface locations. Impact experiments were carried out to analyze bruising patterns in three zones in a fruit surface, i.e., middle/cheek-to-top/stem, middle-to-middle and middle-to-bottom/calyx. Moving fruit and stationary fruit were impacted using a pendulum-type test device, and an equivalent drop height of fruit was calculated to provide a more practical measure for designing a catching surface. In each impact zone, seven different levels of impacts were applied respectively at seven different locations on the fruit surface. Those locations were evenly distributed along the circumferential direction in each of the three zones, and moving fruit was replaced after each impact test. The United States Department of Agriculture (USDA) standard was then used to estimate percentages of fruit in the Extra Fancy Class 1 (no bruising), Extra Fancy (a bruising area diameter ≤ 12.7 mm) and Fresh Market (a bruising area diameter ≤ 19 mm) grades. Results showed that fruit bruising severity increased in a non-linear manner with increasing drop height. It was also found that there existed significant differences in fruit bruising severity between stationary and moving fruit under different fruit-to-fruit impact zones. The bottom zone showed the least bruising sensitivity, followed by the middle zone which was statistically similar to the same in the top zone. The results suggested that the free drop height need to be <3 cm to keep from fruit bruising caused by apple-to-apple impact at a negligible level for ‘Jazz’ apples

    Significant Synergistic Effect between Supported Ruthenium and Copper Oxides for Propylene Epoxidation by Oxygen

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    National Basic Research Program of China [2010CB732303]; NSF of China [21173172, 20873110, 21033006]; Key Scientific Projects of Fujian Province [2009HZ002-1]; Program for Changjiang Scholars and Innovative Research Team in University [IRT1036

    Oral Supplements of Combined Bacillus licheniformis Zhengchangsheng® and Xylooligosaccharides Improve High-Fat Diet-Induced Obesity and Modulate the Gut Microbiota in Rats

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    Gut dysbiosis induced by high-fat diet (HFD) may result in low-grade inflammation leading to diverse inflammatory diseases. The beneficial effects of probiotics and prebiotics on obesity have been reported previously. However, their benefits in promoting human health and the underlying mechanisms still need to be further characterized. This study is aimed at understanding how probiotic Bacillus licheniformis Zhengchangsheng® (BL) and prebiotic xylooligosaccharides (XOS) influence the health of a rat model with HF (60 kcal %) diet-induced obesity. Five groups of male Sprague Dawley (SD) rats were fed a normal fat diet (CON) or an HFD with or without BL and XOS supplementation for 3 weeks. Lipid profiles, inflammatory biomarkers, and microbiota composition were analyzed at the end of the experiment. Rats fed an HFD exhibited increased body weight and disordered lipid metabolism. In contrast, combined BL and XOS supplementation inhibited body weight gain and returned lipid metabolism to normal. Furthermore, BL and XOS administration changed the gut microbiota composition and modulated specific bacteria such as Prevotellaceae, Desulfovibrionaceae, and Ruminococcaceae. In addition, supplements of combined BL and XOS obviously reduced the serum LPS level, which was significantly related to microbial variations. Our findings suggest that modulation of the gut microbiota as a result of probiotic BL and prebiotic XOS supplementation has a positive effect on HFD-induced obesity in rats

    Selective oxidation of methane to formaldehyde by oxygen over silica-supported iron catalysts

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    FeOx-SiO2 catalysts prepared by a sol-gel method were studied for the selective oxidation of methane by oxygen. A single-pass formaldehyde yield of 2.0% was obtained over the FeOx-SiO2 with an iron content of 0.5 wt% at 898 K This 0.5 wt% FeOx-SiO2 catalyst demonstrated significantly higher catalytic performances than the 0.5 wt% FeOx-SiO2 prepared by an impregnation method. The correlation between the catalytic performances and the characterizations with UV-Vis and H-2-TPR suggested that the higher dispersion of iron species in the catalyst prepared by the sol-gel method was responsible for its higher catalytic activity for formaldehyde formation. The modification of the FeOx-SiO2 by phosphorus enhanced the formaldehyde selectivity, and a single-pass formaldehyde yield of 2.4% could be attained over a P-FeOx-SiO2 catalyst (P/Fe = 0.5) at 898 K Raman spectroscopic measurements indicated the formation of FePO4 nanoclusters in this catalyst, which were more selective toward formaldehyde formation.National Natural Science Foundation of China [20625310, 20773099, 20873110]; National Basic Program of China [2005CB221408]; National Science Fund for Talent Training in Basic Science [J0630429

    Significant Synergistic Effect between Supported Ruthenium and Copper Oxides for Propylene Epoxidation by Oxygen

    No full text
    National Basic Research Program of China [2010CB732303]; NSF of China [21173172, 20873110, 21033006]; Key Scientific Projects of Fujian Province [2009HZ002-1]; Program for Changjiang Scholars and Innovative Research Team in University [IRT1036]Significant synergistic effects exist between RuOx and CuOx for the propylene epoxidation by oxygen. While supported CuOx and RuOx alone both catalyzed the formation of acrolein as the main partial oxidation product, the combination of RuOx and CuOx in an appropriate ratio afforded an efficient and stable epoxidation catalyst. The supported nanocomposites with the direct contact interface between CuOx and RuOx were proposed for propylene oxide formation (see figure)

    Active site and reaction mechanism for the epoxidation of propylene by oxygen over CuOx/SiO2 catalysts with and without Cs + modification

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    Among alkali metal ions, Cs+ was found to be the most efficient promoter of the CuOx/SiO2 catalyst for the epoxidation of propylene to propylene oxide (PO) by O2. Stronger interactions between Cs+ and CuOx nanoparticles were proposed to favor the selective formation of PO. Kinetic studies indicated that PO was formed as a primary product in parallel with acrolein over the CuOx/SiO 2 catalyst, but PO readily underwent isomerization to allyl alcohol, followed by oxidation to acrolein, without Cs+ modification. The modification by Cs+ inhibited the isomerization of PO because of the weakened acidity, contributing to the increase in PO selectivity. The inhibition of the reactivity of the lattice oxygen in the presence of Cs+ also promoted PO selectivity by suppressing the allylic oxidation route. In situ X-ray diffraction, CO-adsorbed Fourier-transform infrared, and pulse-reaction studies suggest that CuI sites generated during the reaction account for the epoxidation of propylene by O2. ? 2012 Elsevier Inc. All rights reserved

    Active site and reaction mechanism for the epoxidation of propylene by oxygen over CuOx/SiO2 catalysts with and without Cs+ modification

    No full text
    National Basic Program of China [2010CB732303]; Natural Science Foundation of China [21173174, 21033006, 21161130522, 20923004]; Program for Changjiang Scholars and Innovative Research Team in University [IRT1036]; Key Scientific Project of Fujian Province [2009HZ0002-1]Among alkali metal ions, Cs+ was found to be the most efficient promoter of the CuOx/SiO2 catalyst for the epoxidation of propylene to propylene oxide (PO) by O-2. Stronger interactions between Cs+ and CuOx nanoparticles were proposed to favor the selective formation of PO. Kinetic studies indicated that PO was formed as a primary product in parallel with acrolein over the CuOx/SiO2 catalyst, but PO readily underwent isomerization to ally] alcohol, followed by oxidation to acrolein, without Cs+ modification. The modification by Cs+ inhibited the isomerization of PO because of the weakened acidity, contributing to the increase in PO selectivity. The inhibition of the reactivity of the lattice oxygen in the presence of Cs+ also promoted PO selectivity by suppressing the allylic oxidation route. In situ X-ray diffraction, CO-adsorbed Fourier-transform infrared, and pulse-reaction studies suggest that Cu-I sites generated during the reaction account for the epoxidation of propylene by O-2. (c) 2012 Elsevier Inc. All rights reserved
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