198,766 research outputs found
Characterization of Pt-M/MCM-41 (M=La, Ce, W) and its catalytic performances in toluene oxidation
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Local structure and photocatalytic activity of B2O3-SiO2/TiO2 ternary mixed oxides prepared by sol-gel method
No full textThe local structure and the photoactivity of B2O3-SiO2/TiO2 ternary mixed oxides (SiO2 content was fixed as 30 at.% with respect to TiO2) was investigated by using XRD. FF-IR, BET, UV-vis spectra, and electron paramagnetic resonance (EPR) measurement. In FT-IR analysis, boron was incorporated into the framework of titania matrix with replacing Ti-O-Si with Si-O-B or Ti-O-B bonds. Also, paramagnetic species such as O- and Ti-3 defects were formed by the boron incorporation. In SiO2/TiO2 mixed oxides, a blue shift in the light absorption band was observed due to the quantization of band structure. All B2O3-SiO2/TiO2 samples had pure anatase phase and no rutile phase was formed even though the calcination temperature was over 900degreesC. Incorporating boron oxides of more than 10% enlarges the grain size of anatase phase and causes a red shift of the light absorption spectrum. The surface area was monotonically decreased with increasing the content of boron content. As a result, the photoactivity of B2O3-SiO2/TiO2 ternary mixed oxides was greatly influenced by the content of boron oxide. The highest photoactivity (g moles/min 1) was obtained when the boron content was 5% and seven times higher than that of silica/titania binary mixed oxide. In addition, the specific photoactivity (g moles/m(2)l) was maximum still at 5%. It was concluded that the large reduction of surface area, the change of band structure, and more formation of bulk Ti3+ sites are responsible for the deterioration in the photoactivity of BiO3-SiO2/TiO2 ternary mixed oxides when the content of boron is over 10%, although their crystallinity was enhanced by increasing the calcination temperature with keeping anatase phase. (C) 2004 Elsevier B.V. All rights reserved.Department of Chemical Engineering, KAIST is supported by the Brain Korea 21 project. S.B. Park would like to give special thanks to the Center for Ultramicrochemical
Process Systems (CUPS) for supporting part of this research and S.K. Ihm would like to thank for the support of National Research Laboratory (NRL) for Environmental Catalysis
Pervaporation of Water-Ethanol Mixtures through Sulfonated Polystyrene Membranes Prepared by Plasma Graft-Polymerization
No full textDifferent membranes which permeate water selectively from water-ethanol mixtures were prepared by plasma graft-polymerization of styrene onto porous poly(vinylidene fluoride) (PVDF) films, by sulfonation of the grafted membranes, and by ionization of the sulfonated membranes, respectively. The permselectivities of the grafted (g-PS), sulfonated (g-PSS) and sodium salt form of sulfonated (g-PSS-Na+) membranes were investigated in view of the feed composition of the water-ethanol mixture and the grafted amount of polystyrene (PS). It was found that the permselectivity increased with the ethanol concentration in the feed and that the grafted amount should be controlled for optimum separation of water. The g-PSS-Na+ membrane with a grafted amount of PS of 0.14 mg/cm(2) was found to have a high permeation rate of 6.6 kg/m(2)h, and a separation factor of 21 for the pervaporation of aqueous 60 wt% ethanol solution at 50 degrees C
Validation of INOE Perception Surveys (INOE-PS)
No full textDevelopment and validation of new items for the Inventory of Nonordinary Experiences (INOE; Taves et al., in prep), using the Response Process Evaluation (RPE) method (Wolf et al., 2021). These new questions are designed to investigate the role of perception in experiences of non-ordinary presences.
Taves, A., Ihm, E. D., Wolf, M. G., Barlev, M., Kinsella, M., & Vyas, M. (2023, February 19). The Inventory of Nonordinary Experiences (INOE): Evidence of Validity in the United States and India. https://doi.org/10.31234/osf.io/r6bw9
Wolf, M. G., Ihm, E., Maul, A., & Taves, A. (2021). Survey Item Validation. In S. Engler & M. Stausberg (Eds.), Routledge Handbook of Research Methods in the Study of Religion: Vol. 2nd edition. Routledge. https://share.osf.io/preprint/460FF-5A1-E1
Catalytic Gasification of Glucose over Ni/Activated Charcoal in Supercritical Water
No full textGasification of glucose was carried out over the 16 wt% Ni/activated charcoal in supercritical water at 28 MPa. Effects of temperature 575-725 degrees C), feed concentration (0.3-0.9 M), and LHSV (6-24 h(-1)) were investigated on the product distribution. For comparison, the gasification experiments were performed with activated charcoal and also without catalyst. While the Ni/activated charcoal catalyst showed a good yield of hydrogen, it was deactivated due to coke deposition especially at low temperatures below 650 degrees C and also due to sintering of nickel particles.This work was financially supported by Ministry of Environment,
Republic of Korea, through KIEST
Novel bidentate phosphine modified Pd(acac)(2)/BF3OEt2 catalyst system for the homopolymerization of alkylnorbornenes and copolymerization with norbornene
No full textThe Pd(acac)(2) + nPh(2)P(CH2)(m) PPh2 + 25BF(3)OEt(2), n = 1-3, m = 1-6, catalyst system has been successfully employed for the homopolymerization of 5-alkyl-2-norbornenes and their copolymerization with norbornene. For this series, the most efficient catalyst system was Pd(acac)(2) + 2Ph(2)P(CH2)(4)PPh2 + 25BF(3)OEt(2). The activity of the catalyst system is comparable to that of most active late transition metal catalysts described in the literature. Bidentate phosphines containing bridges larger than 1,4-butane are likely to act as monodentate ligands. The incorporations of flexible alkyl groups Onto the main chain of norbornene, as well as copolymerization of 5-alkyl-2-norbornenes with norbornene, represent a useful method for lowering the glass transition temperature (T.), i.e. improving the processability. The introduction of bidentate phosphine ligand to the Pd(acac)(2) + 25BF(3)OEt(2) system switched the carbocationic polymerization mechanism to the coordination Ziegler-Natta polymerization. The simplicity of this catalytic system composition might be of industrial importance. (c) 2005 Elsevier B.V. All rights reserved
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
Sorption selectivity of NaY- and KY- zeolites for xylene and toluene
No full textThe selective adsorption capacities of NaY- and KY-zeoliles for xylene isomers and toluene were investigated by measuring the rate of unidirectional diffusion in a batch adsorber and the breakthrough behavior in a fixed-bed column. The sequence of sorption selectivity was found as m-xylene ~>toluene ~. p-xylene with NaY-zeolites and as the converse with KY-zeolites. The reversal of selectivity could not be explained by the molecular sieving effects but by the interactions between adsorbing molecules and cation as well as among adsorbing molecules themselves
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