Detailed mechanism and kinetic study of CO oxidation on cobalt oxide surfaces

Co3O4 catalysts were prepared by combustion synthesis using different fuels glycine (G), ODH (O) and urea (U). Morphological changes of the materials were observed by using different fuels. The prepared catalysts were characterized by XRD, XPS, SEM, TEM, BET and DRIFTS analysis. All compounds showed 100% conversion of CO below 175C. The prepared catalysts exhibited very high stability and conversions did not decrease even after 50 h of continuous operation. The oxygen storage capacity (OSC) of materials was measured by H-2-TPR analysis. Co3O4-O is having high OSC among the synthesized catalysts. The activation energies of these catalysts were found to be in the range of 42.3-64.8 kJ mol(-1). With DRIFTS analysis, the surface carbonates, superoxide anions, adsorbed CO, O-2 species on the catalyst surface were found and this information was used to develop a detailed reaction pathway. A kinetic model was developed with the help of proposed mechanism and used to fit the data. (C) 2014 Elsevier B.V. All rights reserved.

Ag-doped hydroxyapatite as efficient adsorbent for removal of Congo red dye from aqueous solution: Synthesis, kinetic and equilibrium adsorption isotherm analysis

In the present study a versatile and efficient adsorbent with high adsorption capacity for adsorption of Congo red dye in aqueous solution at ambient temperature without adjusting any pH is presented over the Ag modified calcium hydroxyapatite (CaHAp). CaHAp and Ag-doped CaHAp materials were synthesized using facile aqueous precipitation method. The physico-chemical properties of the materials were determined by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Transmission electron microscopy (TEM), UV-Visible spectroscopy, N-2 physisorption and acidity was determined by n-butylamine titration and pyridine adsorption methods. XRD analysis confirmed all adsorbents exhibit hexagonal CaHAp structure with P6(3)/m space group. TEM analysis confirms the rod like morphology of the adsorbents and the average length of the rods were in the range of 40-45 nm. Pyridine adsorption results indicate increase in number of Lewis acid sites with Ag doping in CaHAp. Adsorption capacity of CaHAp was found increased with Ag content in the adsorbents. Ag (10): CaHAp adsorbent showed superior adsorption performance among all the adsorbents for various concentrations of Congo red (CR) dye in aqueous solutions. The amount of CR dye adsorbed on Ag (10): CaHAp was found to be 49.89-267.81 mg g(-1) for 50-300 ppm in aqueous solution. A good correlation between adsorption capacity and acidity of the adsorbents was observed. The adsorption kinetic data of adsorbents fitted well with pseudo second-order kinetic model with correlation coefficients ranged from 0.998 to 0.999. The equilibrium adsorption data was found to best fit to the Langmuir adsorption isotherm model. (C) 2015 Elsevier Inc. All rights reserved.

ASYMPTOTIC PRESERVING SCHEME FOR A KINETIC MODEL DESCRIBING IN COMPRESSIBLE FLUIDS

The kinetic theory of fluid turbulence modeling developed by Degond and Lemou in 7] is considered for further study, analysis and simulation. Starting with the Boltzmann like equation representation for turbulence modeling, a relaxation type collision term is introduced for isotropic turbulence. In order to describe some important turbulence phenomenology, the relaxation time incorporates a dependency on the turbulent microscopic energy and this makes difficult the construction of efficient numerical methods. To investigate this problem, we focus here on a multi-dimensional prototype model and first propose an appropriate change of frame that makes the numerical study simpler. Then, a numerical strategy to tackle the stiff relaxation source term is introduced in the spirit of Asymptotic Preserving Schemes. Numerical tests are performed in a one-dimensional framework on the basis of the developed strategy to confirm its efficiency.

Kinetic and Size Control of Polystyrene and Polyacrylic Octadecyl Ester Lattices Via Polymerization in O/W Microemulsions

The kinetic studies of the acrylic octadecyl ester and styrene polymerization in microemulsion systems, (1) cetyl pyridine bromide (CPDB)/t-butanol/styrene/water; (2) CPDB/t-butanol/toluene + acrylic octadecyl ester (1:1, w/v)/ water; (3) cetyl pyridine bromide/styrene/formamide, were made by using dynamic laser light scattering techniques (DLS). The mechanisms of nucleation of latex particles were discussed. The most possible nucleation location of the styrene and acrylic octadecyl ester microlatex particles in aqueous microemulsion system is in aqueous phase via homogeneous nucleation. Meanwhile, parts of microlatex particles are possibly produced via swollen micelles (microemulsions) and monomer droplets nucleation. On the other hand, the most possible nucleation location of the styrene microlatex particles in nonaqueous microemulsion system is inside monomer droplets. The relationship between the amount of monomer and the size of microlatex was also investigated. It has been found that the size of microlatex particles could be controlled by changing the amount of monomer. (C) 2002 Elsevier Science B.V. All rights reserved.

Kinetic measurements of cell surface E-selectin/carbohydrate ligand interactions

Selectin/ligand interactions initiate the multistep adhesion and signaling cascades in the recruitment of leukocytes from circulation to inflamed tissues and may also play a role in tumor metastasis. Kinetic properties of these interactions are essential determinants governing blood-borne cells' tethering to and rolling on the vessel wall. Extending our recently developed micropipette method, we have measured the kinetic rates of E-selectin/ligand interactions. Red cells coated with an E-selectin construct were allowed to bind HL-60 or Colo-205 cells bearing carbohydrate ligands. Specific adhesions were observed to occur at isolated points, the frequency of which followed a Poisson distribution. These point attachments were formed at the same rate with both the HL-60 and Colo-205 cells (0.14 +/- 0.04 and 0.13 +/- 0.03 mum(2) s(-1) per unit density of E-selectin, respectively) but dissociated from the former at a rate twice as fast as did from the latter (0.92 +/- 0.23 and 0.44 +/- 0.10 s(-1), respectively). The reverse rates agree well with those measured by the flow chamber. The forward rates are orders of magnitude higher than those of Fc gamma receptors interacting with IgG measured under similar conditions, consistent with the rapid kinetics requirement for the function of E-selectin/ligand binding, which is to capture leukocytes on endothelial surfaces from flow.

Kinetic Assessment of Measured Mass Flow Rates and Streamwise Pressure Distributions in Microchannel Gas Flows

Measured mass flow rates and streamwise pressure distributions of gas flowing through microchannels were reported by many researchers. Assessment of these data is crucial before they are used in the examination of slip models and numerical schemes, and in the design of microchannel elements in various MEMS devices. On the basis of kinetic solutions of the mass flow rates and pressure distributions in microchannel gas flows, the measured data available are properly normalized and then are compared with each other. The 69 normalized data of measured pressure distributions are in excellent agreement, and 67 of them are within 1 +/- 0.05. The normalized data of mass flow-rates ranging between 0.95 and 1 agree well with each other as the inlet Knudsen number Kn (i) < 0.02, but they scatter between 0.85 and 1.15 as Kn (i) > 0.02 with, to some extent, a very interesting bifurcation trend.

The art of human rights : enriching the life of the law school through drawings and other visual resource

In the life of the Law School, focus on the “visual” can operate at three different levels: learning, teaching, and examining (legal concepts). My main interest in this paper is to explore the latter level, “examining”, broadly considered so as to encompass evaluation in general. Furthermore, that interest is pinned down here to the area of constitutional rights and human rights in general, even though the conclusions reached can (and should) likely be extrapolated to other areas of the law... In effect, the first logical step regarding the relevance of the visual approach has to do with using it yourself when you study —assuming that you came to the conclusion that you are a “visual learner”. As you know, VARK theorists propose a quadripartite classification of learners. The acronym VARK stands for Visual, Aural, Read/write, and Kinesthetic sensory modalities that are used for learning information. This model was designed in the late 80s by Neil Fleming and it has received some acceptance and a lot of attention...