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Ionescu N.I.,Ilie Murgulescu Institute of Physical Chemistry
Revue Roumaine de Chimie | Year: 2011

An overall kinetic model is presented explaining the appearance of some kinetic instabilities in heterogeneous solid-gas systems. The model is based on adsorption-desorption phenomena and surface chemical reactions. The obtained results are discussed. Source

Ionescu N.I.,Ilie Murgulescu Institute of Physical Chemistry
Revue Roumaine de Chimie | Year: 2010

An overall kinetic model is presented which explains the appearance of some kinetic instability in heterogeneous catalytic oxidation reactions. The model is based on the reactions of subsurface oxygen in the subsurface layer. Source

Dragoescu D.,Ilie Murgulescu Institute of Physical Chemistry
Journal of Chemical Thermodynamics | Year: 2014

Densities and refractive indices data for five binary systems of 2-butanone + 1-chloropentane, + 1,3-dichloropropane, + 1,4-dichlorobutane, + 1,1,1-trichloroethane, + 1,1,2,2-tetrachloroethane were measured at T = 298.15 K and atmospheric pressure, over the entire mole fraction range. The densities data of the studied mixtures have been used to calculate the excess molar volumes and the partial volumetric properties at infinite dilution. The refractive index data were used to calculate excess molar refractions and the deviations of experimental refraction indices from the predicted results were compared with those calculated using several mixing rules (Lorentz-Lorenz, Gladstone-Dale, Arago-Biot, Edwards, Eykman). The excess quantities were fitted to a Redlich-Kister type polynomial equation to derive the binary coefficients and estimate the standard deviations between the experimental and calculated quantities. The excess molar volumes and the excess molar refraction have evidenced intermolecular interactions between the components of mixtures. © 2014 Elsevier Ltd. All rights reserved. Source

Teodorescu M.,Ilie Murgulescu Institute of Physical Chemistry
Industrial and Engineering Chemistry Research | Year: 2014

Experimental isothermal vapor + liquid equilibrium (VLE) data are reported for the binary mixture containing 1-butyl-3-methylimidazolium bromide ([bmim]Br) + 1-butanol at three temperatures, 353.15, 363.15, and 373.15 K, in the range of 0-0.321 liquid mole fraction of [bmim]Br. Additionally, refractive index measurements have been performed at two temperatures, 298.15 and 308.15 K in the whole composition range. Densities, excess molar volumes, surface tensions, and surface tension deviations of the binary mixture were predicted by Lorenz-Lorentz (nD-ρ) mixing rule. Dielectric permittivities and their deviations were evaluated by known equations. Vapor + liquid equilibrium data were correlated with the Wilson thermodynamic model while refractive index data were correlated by the 3-parameters Redlich-Kister equation. The studied mixture presents positive abatement from Raoults law. Similarly, positive refractive index deviations are obtained. The VLE data may be used in separation processes design, and the thermophysical properties may be used as key parameters in specific applications. © 2014 American Chemical Society. Source

Stanoiu A.,National Institute of Materials Physics Bucharest | Simion C.E.,National Institute of Materials Physics Bucharest | Somacescu S.,Ilie Murgulescu Institute of Physical Chemistry
Sensors and Actuators, B: Chemical | Year: 2013

In order to understand the role of ambient humidity on NO2 detection, electrical resistance and work function changes were recorded simultaneously on ZnO-Eu2O3 material. Thus, surface band bending and electron affinity could be evaluated, according to the Schottky model. The lack of electron affinity changes during NO2 exposure in dry air conditions, reveals that only the free charge concentration is affected. Exposure to NO2 in humid background leads to an increase in sensor signals and a significant change in the electron affinity as well. This effect suggests an interaction between NO2 and surface hydroxyl species; thereby additional charge carriers are involved in the overall sensing process. High resolution XPS analysis proves the presence of Eu solely in the 3 + oxidation state before and after NO2 exposure. A gas-sensing interaction mechanism has been proposed. © 2013 Elsevier B.V. All rights reserved. Source

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