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991.
The catalytic destruction of volatile organic compound (VOC) benefits from a low oxidation temperature due to less energy consumption. In this study, activated carbon-supported Pt catalysts were prepared for benzene, toluene and xylene (BTX) deep oxidation at below 200°C. Activated carbon can serve as a media for concentrating VOC. The carbon supports were heated to 400 or 800°C under N2 flow and washed with HF acid to remove surface impurities and/or minerals. The 0.3 wt.% Pt/activated carbon catalysts were prepared by the incipient wetness method, followed by H2 reduction at 300°C for 2 h. The catalytic oxidation was conducted with a BTX concentration ranging from 640 to 2000 ppmv in air at volume hour space velocity (VHSV) of approximately 21 000 h−1. The light-off curves were very steep and the light-off temperatures ranged between 130 and 150°C, well below those of the Pt/Al2O3 catalyst. The oxidation activity was promoted because of a higher surface BTX concentration due to the adsorption capability of activated carbons. Moisture reduces the activity only slightly due to the hydrophobicity of activated carbon. Generally, the Pt catalysts with thermally-treated activated carbon had lower ignition temperatures. Experimental results indicated that high-temperature pretreatment of activated carbon could effectively increase the catalyst activity. Meanwhile, X-ray photoelectron spectroscopy (XPS)/secondary ion mass spectroscopy (SIMS) investigation revealed that the graphitized surface might play a role in catalytic activity. Finally, this work suggested a reaction mechanism based on the adsorption-migration of hydrocarbons to reveal the enhanced activity of activated carbon support. 相似文献
992.
Recently, there has been an increasing interest in mobile ad hoc networks. In a mobile ad hoc network, each mobile node can freely move around and the network is dynamically constructed by collections of mobile nodes without using any existing network infrastructure. Compared to static networks, it faces many problems such as the inefficiency of routing algorithms. Also, the number of control packets in any routing algorithm increases as the mobile speed or the number of mobile nodes increases. Most of the current routing protocols in ad hoc networks broadcast the control packets to the entire network. Therefore, by reducing the number of control packets, the efficiency of the network routing will be improved. If we know where the destination is, we can beam our search toward that direction. However, without using global positioning systems, how can we do this? Define the range nodes as the 1‐hop or 2‐hop neighbors of the destination node. In this paper, we propose using the range nodes to direct our searches for the destination. It can be combined with the existing routing protocols to reduce the control overhead. We show through simulations that AODV and DSR combined with the range node method outperforms the original AODV and DSR routing protocols in terms of control packets overhead. We also show that the delay introduced in find range nodes is insignificant. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
993.
C. A. Chen Y. S. Huang W. H. Chung D. S. Tsai K. K. Tiong 《Journal of Materials Science: Materials in Electronics》2009,20(Z1):303-306
Raman spectroscopy (RS) was used to study the phase transformations of nanocrytalline TiO2 thin films. The films were grown by a vertical-flow cold-wall metal organic chemical vapour deposition system, using Ti(C10H14O5) as the source reagent, at different substrate temperatures. The results indicate that the anatase phase is present at around
550 °C and the rutile phase starts to form at 620 °C. The anatase phase completely transforms into the rutile phase at 680 °C.
We have demonstrated that RS can be used as a powerful nondestructive technique for a quick and efficient determination of
the phase of TiO2 thin films. 相似文献
994.
Ming-Chin Lu Yen-Ting Huang Jia-Horng Lin Chun-Hsu Yao Ching-Wen Lou Chin-Chuan Tsai Yueh-Sheng Chen 《Journal of materials science. Materials in medicine》2009,20(5):1175-1180
We evaluated peripheral nerve regeneration using a biodegradable multi-layer microbraided polylactic acid (PLA) fiber-reinforced
conduit. Biodegradability of the PLA conduit and its effectiveness as a guidance channel were examined as it was used to repair
a 10 mm gap in the rat sciatic nerve. As a result, tube fragmentation was not obvious and successful regeneration through
the gap occurred in all the conduits at 8 weeks after operation. These results indicate the superiority of the PLA materials
and suggest that the multi-layer microbraided PLA fiber-reinforced conduits provide a promising tool for neuro-regeneration.
Ming-Chin Lu, Chun-Hsu Yao, and Yueh-Sheng Chen are contributed equally to this work. 相似文献
995.
In this study, municipal solid waste incinerator fly ash was vitrified using a plasma torch. The fly ash contained rich Ca, causing a high basicity of 2.43. Pure quartz was used as an additive to adjust the basicity. BET surface area analysis, X-ray diffraction analysis, and a scanning electron microscope were used to examine the physical properties of slags. The chemical stability and the acid resistance of slags were evaluated using the toxicity characteristics leaching procedure and tests of acid bathing. The results indicate that the plasma torch effectively vitrified the fly ash. Anthropogenic metals with low boiling points, such as Cd, Pb, and Zn, were predominately vaporized into flue gas. Most of the metals with high boiling points, such as Cr, Cu, and Mn, remained in the slag. After the vitrification, hazardous metals were noticeably immobilized in all slags. However, the slags with higher amorphous volume fractions were more effective in metal immobilization and in resisting acid corrosion. This indicates that SiO(2) enhanced the formation of the glassy amorphous phase and improved the resistance of acid corrosion and the immobilization of hazardous metals. 相似文献
996.
The removal efficiency of tetrafluoromethane (CF(4)) was significantly enhanced by adding additives (H(2), O(2), H(2)+O(2), H(2)O) in an atmospheric-pressure microwave plasma reactor. However, large amounts of fluorine (F(2)) were produced in this study. Moreover, the selectivity of F(2) was apparently greater than that of HF (in H(2)-based condition) or COF(2) (in O(2)-based abatement). Notably, in an O(2)-rich environment, more F(2) and a larger amount of CO(2) were produced. Subsequently, F(2) can be effectively removed by reacting with CaO to form CaF(2) at 200 degrees C via an in situ dry, chemical absorption process in the low-temperature afterglow discharge zone within the same plasma reactor. 相似文献
997.
The industrial solvent trichloroethylene (TCE) is among the most ubiquitous chlorinated solvents found in groundwater contamination. The main objectives of this study were to evaluate the feasibility of using non-ionic surfactant Simple Green™ (SG) to enhance the oxidative dechlorination of TCE by potassium permanganate (KMnO4) employing a continuous stir batch reactor system (CSBR) and column experiments. The effect of using surfactant SG to enhance the biodegradation of TCE via aerobic cometabolism was also examined. Results from CSBR experiments revealed that combination of KMnO4 with surfactant SG significantly enhanced contaminant removal, particularly when the surfactant SG concentrated at its CMC. TCE degradation rates ranged from 74.1% to 85.7% without addition of surfactant SG while TCE degradation rates increased to ranging from 83.8% to 96.3% with presence of 0.1 wt% SG. Furthermore, results from column experiments showed that TCE was degraded from 38.1 μM to 6.2 μM in equivalent to 83.7% of TCE oxidation during first 560 min reaction. This study has also demonstrated that the addition of surfactant SG is a feasible method to enhance bioremediation efficiency for TCE contaminated groundwater. The complete TCE degradation was detected after 75 days of incubation with both 0.01 and 0.1 wt% of surfactant SG addition. Results revealed that surfactant enhanced chemical oxidation and bioremediation technology is one of feasible approaches to clean up TCE contaminated groundwater. 相似文献
998.
A Taguchi and experimental investigation into the optimal processing conditions for the abrasive jet polishing of SKD61 mold steel 总被引:1,自引:0,他引:1
F.C. Tsai B.H. Yan C.Y. Kuan F.Y. Huang 《International Journal of Machine Tools and Manufacture》2008,48(7-8):932-945
This study introduces an abrasive jet polishing (AJP) technique in which the pneumatic air stream carries not only abrasive particles, but also an additive of either pure water or pure water with a specified quantity of machining oil. Taguchi design experiments are performed to identify the optimal AJP parameters when applied to the polishing of electrical discharge machined SKD61 mold steel specimens. A series of experimental trials are then conducted using the optimal AJP parameters to investigate the respective effects of the additive type and the abrasive particle material and diameter in achieving a mirror-like finish of the polished surface. The Taguchi trials indicate that when polishing is performed using pure water as an additive, the optimal processing parameters are as follows: an abrasive material to additive ratio of 1:2, an impact angle of 30°, a gas pressure of 4 kg/cm2, a nozzle-to-workpiece height of 10 mm, a platform rotational velocity of 200 rpm, and a platform travel speed of 150 mm/s. Applying these processing parameters, it is found that the optimal polishing effect is attained using #8000SiC abrasive particles and a 1:1 mixture of water-solvent machining oil and pure water. The experimental results show that under these conditions, the average roughness of the electrical discharge machined SKD61 surface is reduced from an original value of Ra=1.03 μm (Rmax: 7.74 μm) to a final value of Ra=0.13 μm (Rmax: 0.90 μm), corresponding to a surface roughness improvement of approximately 87%. 相似文献
999.
Immersion Ni-P deposition is undoubtedly one of the most important catalytic deposition process, due to its simplicity in operation and low equipment cost. In this study, immersion deposited Ni-P films were used to form Ni-silicide films. Ni-P films with a thickness of 100 nm were fabricated by immersing Si(100) substrates in an aqueous deposition solution. Ni-silicide films were then formed by annealing the samples in a furnace at temperatures ranging from 400 °C to 900 °C for 1 h in an argon ambient. Experimental results indicate that a phosphor addition in Ni films increased the transformation temperature of NiSi to NiSi2 to 900 °C. Moreover, the feasibility of enhancing the thermal stability of NiSi by varying the interface energy at the NiSi2/Si interface and the surface energy of a Ni-P-Si capping layer on the NiSi surface is discussed. 相似文献
1000.
V. A. Kalitko Morgan Chun Yao Wu V. A. Zhdanok Benson Ching Tsai Yo 《Journal of Engineering Physics and Thermophysics》2009,82(2):236-245
This paper presents the process of steam thermolysis of shredded used tires for obtaining from them liquid fuel and technical
carbon carried out in a screw reactor with heating due to the partial burning of obtained fuel and burning of the tail combustible
gas. The features and advantages of using steam for safety and stability of the process, including the problem of secondary
waste slime processing, have been considered. The specific fuel consumption and the steam generation per 1 kg of processed
tires and, separately, the gas consumption for power supply (heating) of the process without using fuel, as well as with additional
burning of fuel for processing slime together with tires, have been considered.
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 82, No. 2, pp. 242–251, March–April, 2009. 相似文献