Search results for "Rut"
showing 10 items of 2295 documents
Che imprevisti a Sunny Island! Un divertente ambiente interattivo di apprendimento.
2015
Il software è un innovativo Ambiente Interattivo di Apprendimento sviluppato con Powersim Studio 10 Premium e basato sul Libro intitolato "Che imprevisti a Sunny Island". L'utente, dopo aver letto il libro, avrà modo di approcciare ai principi del pensiero sistemico in modo estremamente pratico attraverso un ambiente di simulazione che, riprendendo gli avvenimenti della storia narrata nel libro, gli consentirà di assumere delle decisioni autonome rispetto a quelle prese dai protagonisti della storia e verificarne gli effetti sul sistema sociale considerato. Ciò permetterà all'utente, tra le altre cose, di comprendere la complessità dell'ambiente sociale descritto nel libro e la natura delle…
Conservazione del paesaggio e dell'ambiente. Governo del territorio e grandi infrastrutture: realtà o utopia?
2009
ENANTIOSELECTIVE REDUCTION OF PROCHIRAL KETONES PROMOTED BY AMINO AMIDE RUTHENIUM COMPLEXES: A DFT STUDY
2021
International audience; The origin of enantioselectivity in the reaction of chiral Ru amino amide complexes in the asymmetric transfer hydrogenation of acetophenone was investigated using DFT calculations. For the most stable active catalysts, the full free energy profiles for the reaction were calculated according to the concerted hydrogen transfer mechanism. We succeeded in reproducing the experimentally observed enantioselectivity for the studied Ru amino amide complexes. Our results indicate that the high enantioselectivity can be explained by a stabilizing CH-π interaction existing between the phenyl group of acetophenone and the aromatic substituent of the catalyst, which plays a sign…
La Cupola del Teatro Massimo: Il contemporaneo nel 1876
2011
FT-ICR MS studies of ion-molecule reactions of Ru+ and Os+ with oxygen
2005
Abstract The reactions of stored ruthenium and osmium cations with oxygen have been studied in a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. In case of osmium the reaction products OsO+ and OsO 2 + have been observed and corresponding reaction-rate constants have been determined. In addition, there is an unreactive fraction of Os+ ions due to the presence of a slightly endothermic reacting ground state. Only the excited states react with oxygen. For ruthenium no spontaneous reaction with oxygen has been observed unless the cyclotron motion of Ru+ was excited. The results are discussed with respect to a similar investigation in a Penning trap-TOF mass spectrometer […
Post-anarchismo in discussione
2015
In this article, the author means to connect the anarchist thought to post-structuralism, deconstructionism, critical theory, french theory, and so on. These strategies of thinking are labelled post-anarchism or neo-anarchism, all tending towards a libertarian affirmation of anti-authoritarian, not-hierarchical and differential equalitarian practices of anarchism.
PHOTOCATALYTIC ACTIVITY OF TIO2 IN ITS POLYMORPHIC FORMS ANATASE, BROOKITE AND RUTILE
2012
Determination of the crystallinity of TiO2 photocatalysts
2018
Abstract This study reports a new simple method to determine the crystallinity of anatase and rutile TiO2 photocatalysts. The crystallinity degree of various anatase and rutile samples was estimated by XRD analysis from the ratio among the full width at half maximum intensities of the main diffraction peaks of anatase or rutile and the (111) peak of CaF2 as internal standard. The photocatalytic activity of selected powders was tested employing the photodegradation of 4-nitrophenol in aqueous solution as probe reaction. The results showed that the photoactivity of the investigated samples increased with increasing crystallinity and crystallite size.
Photocatalytic activity of nanocrystalline TiO2 (brookite, rutile and brookite-based) powders prepared by thermohydrolysis of TiCl4 in aqueous chlori…
2008
Abstract Nanocrystalline TiO2 powders were synthesized by thermohydrolysis of TiCl4 in HCl or NaCl aqueous solutions. Rutile, mixtures of brookite and rutile or mixtures of anatase, brookite and rutile were obtained depending on the acidity of the medium. Crystalline phases and composition of the mixtures were identified by using XRD analysis. Pure brookite nanoparticles, separated from the mixtures of brookite and rutile by simple peptization with water, were stable against transformation to rutile up to 750 °C. The prepared TiO2 powders were characterized by thermal analysis, diffuse reflectance spectroscopy and BET surface area determinations. The band gap of bulky brookite was estimated…
Photocatalytic degradation of phenol in aqueous titanium dioxide dispersions
1988
The results of a study of photocatalytic degradation of phenol using aqueous oxygenated TiO2 (anatase) suspensions in a batch Pyrex photoreactor are reported. The influence on the photodegradation rate of various parameters as pH, phenol and TiO2 content, oxygen partial pressure, anions present in the dispersions was investigated. A complete oxidation of phenol was observed. Intermediate compounds, catechol and quinone, were detected. It was observed that the photodegradation also proceeded with sunlight radiation. A mechanistic and kinetic model, which accounts for the results obtained, is given. Likely reasons for inactivity of the rutile modification for this reaction are also given.