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51.
Partial oxidation of methane into syngas was conducted over fresh and sulfided catalysts at a temperature range of 450–750 °C. The temperature dependence of conversion, H2/CO ratio, and the CO2 concentration were measured for both fresh and sulfided catalysts. Regardless of metal type, metal loading, support type, and the methods of preparation it appears that all the fresh catalysts were very active and conversions of higher than 70% with H2/CO ratio of about 2 were observed at 750 °C. Pulse sulfidation appears to be reversible for some of the catalysts but not for all. Under pulse sulfidation conditions, the Rh(0.5%)/Al2O3 and NiMg2Ox-1100 °C (solid solution) catalysts were fully regenerated after reduction with hydrogen. Rh catalyst showed the best overall activity, less carbon deposition, both fresh and when it was exposed to pulses of H2S. Sulfidation under steady-state conditions, flowing H2S/Ar mixture over the catalysts, significantly reduce catalyst activity. The catalysts were characterized before and after reaction with H2S using temperature-programmed oxidation (TPO) and reduction (TPR), X-ray diffraction, and XPS. 相似文献
52.
Abolghasem Asgari Panos Trimintzios Mark Irons Richard Egan George Pavlou 《Journal of Network and Systems Management》2003,11(4):399-426
Deployment of quality-of-service (QoS) based value-added services in IP networks necessitates the use of traffic engineering. Traffic engineering allows service providers to use the network resources efficiently, according to the different quality levels associated with the range of services they offer. Traffic engineering relies typically on monitoring data for both offline proactive and dynamic reactive approaches. Monitoring data may be used for network provisioning, dynamic resource allocation, route management, and in-service performance verification for value-added IP services. A monitoring system should scale with the network size, the network speed, and the number of customers subscribed to use value-added IP services. This paper investigates the requirements of scalable monitoring system architectures, proposes principles for designing such systems and validates these principles through the design and implementation of a scalable monitoring system for traffic engineering and QoS delivery in IP Differentiated Services networks. Methods for assessing the relative merits of such monitoring systems are proposed. Experimental assessment results prove the scalability, accuracy, and also demonstrate the benefits of the proposed monitoring system. 相似文献
53.
Physical and tensile properties of epoxy laminated magnetic bacterial cellulose nanocomposite films 下载免费PDF全文
Despite many potential applications, the adverse impacts of magnetic nanoparticles on the tensile properties of magnetic cellulose papers and films are well established. On the other hand, water absorption and thickness swelling of cellulose materials are important limiting factors in many engineering applications. These challenges caused limited applications of magnetic cellulose nanocomposites. The aim of this study is to examine the possibility of modifying the physical and mechanical behaviors of magnetic bacterial cellulose films by epoxy resin lamination. Results showed that the tensile modulus and strength of the magnetic bacterial cellulose film, respectively, increased about 280% and 240% after epoxy lamination while they maintained their desirable magnetic and flexibility properties. Furthermore, the water absorption and thickness swelling of the epoxy laminated magnetic nanocomposite films, respectively, improved about 43% and 42%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45118. 相似文献
54.
Abolghasem Shamsi 《Catalysis Letters》1994,25(1-2):97-103
The relative reactivity of ethane and ethylene compared to methane over the Ca/Ni/K catalyst was determined. The reactivities are in the order of ethylene > ethane methane. The catalyst was also studied using temperature-programmed reaction, desorption and decomposition. 相似文献
55.
Zhang Bo Wang Lijun Ghimire Sanjaya Li Xin Todd Matthew Scott Shahbazi Abolghasem 《Clean Technologies and Environmental Policy》2021,23(8):2399-2412
Clean Technologies and Environmental Policy - Biochar can effectively strengthen anaerobic digestion (AD) and improve the treatment efficiency of organic wastes. However, the types of biochar... 相似文献
56.
Forouzan Gholamian Sara Ghariban-Lavasani Mohammad Mehdi Garshasbi Mahdi Ansari Farideh Bataghv Abolghasem Moraveji Zahra Ranjbar 《Polymer Bulletin》2013,70(5):1677-1695
In this study, the dynamic-mechanical properties of fumed silica and silane-treated reinforced epoxy nano-composites were examined; silane-treated specimens demonstrated greater glass transition temperature, modulus, and less moisture absorption. An epoxy composite has been studied under hydrothermal ageing in order to investigate the effect of treatment on dynamical mechanical thermal analysis. The nanocomposites were kept in seawater up to 600 h. The process was then modeled using response surface methodology based on central composite design (CCD). Three models were developed to predict the influence of wet aging parameters on the Tg, modulus, and damping. Accuracy of predicted results was analyzed by the analysis of variance method. The optimum values predicted by the RSM and CCD were 1 % wt treated fumed silica followed by aging at 60 °C. Multiple correlation coefficients (R 2) of 0.96 were obtained from the regression models for Tg, confirming the good accuracy of developed models. 相似文献
57.
58.
LaFe1-x-yCo_xPd_yO_3 [(x, y) =(0, 0),(0.40, 0),(0.38, 0.05)] nanoparticles were synthesized via a co-precipitation route using ammonium hydroxide, sodium hydroxide and ammonium carbonate as the precipitant and calcination at different temperatures to study the compositional driven structural changes in lanthanum ferrites.Analysis of X-ray diffraction(XRD) patterns confirms the formation of single-phase perovskite structure and existence of orthorhombic Pnma symmetry for calcined powders. Field emission scanning electron microscope(FESEM) observations show that Pd-doped powders yield finer particles along with narrower particle size distribution compared with LaFeO_3 and LaFe0.6Co0.4O_3. Moreover,using ammonia as the precipitant leads to a smaller mean particle size of powders compared to NaOH, as well as significant difference in morphology of the particles.Raman analysis reveals that both Co and Pd atoms substitute Fe site in perovskite structure with shifting of phonon modes. Comparing Raman spectra demonstrates the presence of more oxygen vacancies in Pd-doped perovskites. It can be concluded from the results that Pd is successfully incorporated into the perovskite structure by co-precipitation method. 相似文献
59.
David Griffin Jason Spencer Jonas Griem Mohamed Boucadair Pierrick Morand Michael Howarth Ning Wang George Pavlou Abolghasem Asgari Panos Georgatsos 《Communications Magazine, IEEE》2007,45(2):88-95
This article presents an approach to delivering qualitative end-to-end quality of service (QoS) guarantees across the multiprovider Internet. We propose that bilateral agreements between a number of autonomous systems (ASs) result in the establishment of QoS-class planes that potentially extend across the global Internet. The deployment of a QoS-enhanced border gateway protocol (BGP) with different QoS-based route selection policies in each of the planes allows a range of interdomain QoS capabilities to coexist on the same network infrastructure. The article presents simulation results showing the benefits of the approach and discusses aspects of the performance of QoS-enhanced BGP 相似文献
60.
Leili Salehi Hassan Eftekhar Kazem Mohammad Sedigheh Sadat Tavafian Abolghasem Jazayery Ali Montazeri 《Nutrition journal》2010,9(1):2