8 research outputs found
Taller vertical de arquitectura 06
Trabajos presentados por los alumnos en los diferentes talleres de la FAU entre los años 2003 y 2005. SelecciĂłn de ejercicios de los niveles 1 a 6 de la cátedra Pronsato-Capelli-Capelli, sobre los temas: vivienda de fin de semana, conjunto de 6 viviendas, agrupamiento de 12 viviendas con equipamiento comercial y estacionamiento, agrupamiento de 80 viviendas con equipamiento comunitario/comercial, terminal marĂtima, centro de espectáculos.Facultad de Arquitectura y Urbanism
Taller vertical de arquitectura 06
Trabajos presentados por los alumnos en los diferentes talleres de la FAU entre los años 2003 y 2005. SelecciĂłn de ejercicios de los niveles 1 a 6 de la cátedra Pronsato-Capelli-Capelli, sobre los temas: vivienda de fin de semana, conjunto de 6 viviendas, agrupamiento de 12 viviendas con equipamiento comercial y estacionamiento, agrupamiento de 80 viviendas con equipamiento comunitario/comercial, terminal marĂtima, centro de espectáculos.Facultad de Arquitectura y Urbanism
DFT study of the formation of Cd-Ag surface alloys on Ag surfaces
We investigate the feasibility of forming a surface alloy between Ag and Cd on Ag surfaces, employing Density Functional Theory calculations. Six layers slabs are used to model surface alloy systems. Adsorption energies for Cd atoms and a monolayer on Ag(1 1 1) and Ag(1 0 0) surfaces are calculated, and compared with surface alloy formation energies, verifying the energetic preference of Ag and Cd to stay in alloyed form on the surface, as found in different electrochemical experiences for this system. This means that there is an electronic effect which favors this type of phenomenon. An analysis of the charge densities and projected densities of states for the different structures proposed is also performed.Fil: Ambrusi, RubĂ©n Eduardo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de FĂsica del Sur. Universidad Nacional del Sur. Departamento de FĂsica. Instituto de FĂsica del Sur; ArgentinaFil: Garcia, Silvana Graciela. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional del Sur. Departamento de IngenierĂa QuĂmica; Argentina. Universidad Nacional del Sur. Departamento de IngenierĂa QuĂmica. Instituto de IngenierĂa ElectroquĂmica y CorrosiĂłn; ArgentinaFil: Pronsato, Maria Estela. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de FĂsica del Sur. Universidad Nacional del Sur. Departamento de FĂsica. Instituto de FĂsica del Sur; Argentin
Formation of Ag nanowires on graphite stepped surfaces: A DFT study
We investigate the feasibility of obtaining silver nanowires on graphite stepped surfaces theoretically, using density functional theory calculations. Three layer slabs are used to model graphite surfaces with and without defects. Adsorption energies for Ag atoms on graphite surfaces were calculated showing the preference of Ag adatoms to locate on the steps, forming linear structures like nanowires. An analysis of the charge densities and projected densities of states for different structures is also performed.Fil: Ambrusi, RubĂ©n Eduardo. Universidad Nacional del Sur. Departamento de IngenierĂa QuĂmica. Instituto de IngenierĂa ElectroquĂmica y CorrosiĂłn; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca; ArgentinaFil: Garcia, Silvana Graciela. Universidad Nacional del Sur. Departamento de IngenierĂa QuĂmica. Instituto de IngenierĂa ElectroquĂmica y CorrosiĂłn; ArgentinaFil: Pronsato, Maria Estela. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de FĂsica del Sur. Universidad Nacional del Sur. Departamento de FĂsica. Instituto de FĂsica del Sur; Argentin
Underpotential deposition and involved alloy formation of cadmium on silver particles modified HOPG substrates
Cadmium underpotential deposition (UPD) on Ag particles modified highly ordered pyrolytic graphite (HOPG) surfaces, and the involved alloy formation were studied by conventional electrochemical techniques. Voltammetric results indicated that the Cd UPD followed an adsorption behavior different from that observed for massive Ag electrodes and Ag particles supported on vitreous carbon. Nanometer-sized bimetallic Cd–Ag particles were characterized by ex situ atomic force microscopy (AFM). Initially, AFM images show Ag deposits of similar size distributed preferably on HOPG step edges. No remarkable morphological changes are observed on the surface after the subsequent Cd deposition, suggesting that the Cd particles are deposited selectively over the Ag crystals. From the analysis of desorption spectra, employing different polarization times, and density functional theory (DFT) calculations, the formation of a Cd–Ag surface alloy could be inferred.Fil: Ambrusi, RubĂ©n Eduardo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de IngenierĂa QuĂmica; ArgentinaFil: Pronsato, Maria Estela. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de FĂsica del Sur. Universidad Nacional del Sur. Departamento de FĂsica. Instituto de FĂsica del Sur; ArgentinaFil: Garcia, Silvana Graciela. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de IngenierĂa QuĂmica; Argentin
c-C 5 H 5 on a Ni(1 1 1) surface: Theoretical study of the adsorption, electronic structure and bonding
In the present work the ASED-MO method is applied to study the adsorption of cyclopentadienyl anion on a Ni(1 1 1) surface. The adsorption with the centre of the aromatic ring placed above the hollow position has been identified to be energetically the most favourable. The aromatic ring remains almost flat, the H atoms are tilted 17° away from the metal surface. We modelled the metal surface by a two-dimensional slab of finite thickness, with an overlayer of c-C 5 H 5 - , one c-C 5 H 5 - per nine surface Ni atoms. The c-C 5 H 5 - molecule is attached to the surface with its five C atoms bonding mainly with three Ni atoms. The Ni{single bond}Ni bond in the underlying surface and the C{single bond}C bonds of c-C 5 H 5 - are weakened upon adsorption. We found that the band of Ni 5 d z 2 orbitals plays an important role in the bonding between c-C 5 H 5 - and the surface, as do the Ni 6s and 6p z bands.Fil: German, Estefania. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de FĂsica del Sur. Universidad Nacional del Sur. Departamento de FĂsica. Instituto de FĂsica del Sur; ArgentinaFil: Simonetti, Sandra Isabel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de FĂsica del Sur. Universidad Nacional del Sur. Departamento de FĂsica. Instituto de FĂsica del Sur; Argentina. Universidad TecnolĂłgica Nacional. Facultad Regional BahĂa Blanca; ArgentinaFil: Pronsato, Maria Estela. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de FĂsica del Sur. Universidad Nacional del Sur. Departamento de FĂsica. Instituto de FĂsica del Sur; ArgentinaFil: Juan, Alfredo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de FĂsica del Sur. Universidad Nacional del Sur. Departamento de FĂsica. Instituto de FĂsica del Sur; ArgentinaFil: Brizuela, Graciela Petra. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de FĂsica del Sur. Universidad Nacional del Sur. Departamento de FĂsica. Instituto de FĂsica del Sur; Argentin
Density functional theory based-study of 5-fluorouracil adsorption on β-cristobalite (1 1 1) hydroxylated surface: The importance of H-bonding interactions
Silica-based mesoporous materials have been recently proposed as an efficient support for the controlled release of a popular anticancer drug, 5-fluorouracil (5-FU). Although the relevance of this topic, the atomistic details about the specific surface-drug interactions and the energy of adsorption are almost unknown. In this work, theoretical calculations using the Vienna Ab-initio Simulation Package (VASP) applying Grimme’s—D2 correction were performed to elucidate the drug–silica interactions and the host properties that control 5-FU drug adsorption on -cristobalite (1 1 1) hydroxylated surface. This study shows that hydrogen bonding, electron exchange, and dispersion forces are mainly involved to perform the 5-FU adsorption onto silica. This phenomenon, revealed by favorable energies, results in optimum four adsorption geometries that can be adopted for 5-FU on the hydroxylated silica surface. Silanols are weakening in response to the molecule approach and establish H-bonds with polar groups of 5-FU drug. The final geometry of 5-FU adopted on hydroxylated silica surface is the results of H-bonding interactions which stabilize and fix the molecule to the surface and dispersion forces which approach it toward silica (1 1 1) plane. The level of hydroxylation of the SiO2 (1 1 1) surface is reflected by the elevated number of hydrogen bonds that play a significant role in the adsorption mechanisms.Fil: Simonetti, Sandra Isabel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de FĂsica del Sur. Universidad Nacional del Sur. Departamento de FĂsica. Instituto de FĂsica del Sur; Argentina. Universidad TecnolĂłgica Nacional. Facultad Regional BahĂa Blanca; ArgentinaFil: DĂaz Compañy, Andres Carlos Daniel. Provincia de Buenos Aires. GobernaciĂłn. ComisiĂłn de Investigaciones CientĂficas; ArgentinaFil: Pronsato, Maria Estela. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de FĂsica del Sur. Universidad Nacional del Sur. Departamento de FĂsica. Instituto de FĂsica del Sur; ArgentinaFil: Juan, Alfredo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de FĂsica del Sur. Universidad Nacional del Sur. Departamento de FĂsica. Instituto de FĂsica del Sur; ArgentinaFil: Brizuela, Graciela Petra. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de FĂsica del Sur. Universidad Nacional del Sur. Departamento de FĂsica. Instituto de FĂsica del Sur; ArgentinaFil: Lam, Anabel. Universidad de La Habana; Cub
Carbon dots structural characterization by solution-state NMR and UV-visible spectroscopy and DFT modeling
A combination of experimental and theoretical results was used for the structural characterization of Carbon dots (Cdots). The synthesis of the Cdots was performed using glucose as a precursor and via the microwave method (“bottom-up” route) as a simple and environmentally friendly method. The experimental data obtained by UV–visible, fluorescence, IR and solution-state NMR spectroscopy techniques were correlated with density functional theory calculations results. Particularly, the results obtained by solution-state NMR spectroscopy suggested Cdots structures of Polymer dots (PDs) and/or polymer Carbon dots (PCDs) kind. PDs are characterized by being formed only of polymer structures and PCDs by being formed of a small carbonized core surrounded by polymer structures. Calculations allow us to predict the UV–visible absorption and IR spectra behavior of the species detected by the NMR technique, and propose a structure that can explain the experimentally observed features and infer the presence or absence of a carbon core in the proposed structures. Density of states curves were used to analyze and interpret the theoretical spectra peaks. Additionally, a calculation of the IR spectra for the models proposed, was performed. The complement of experimental and theoretical results represents a useful tool for the structural characterization of Cdots.Fil: Arroyave Rodriguez, Jeison Manuel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de QuĂmica del Sur. Universidad Nacional del Sur. Departamento de QuĂmica. Instituto de QuĂmica del Sur; ArgentinaFil: Ambrusi, RubĂ©n Eduardo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de FĂsica del Sur. Universidad Nacional del Sur. Departamento de FĂsica. Instituto de FĂsica del Sur; ArgentinaFil: Robein, Yael Nicolas. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de QuĂmica del Sur. Universidad Nacional del Sur. Departamento de QuĂmica. Instituto de QuĂmica del Sur; ArgentinaFil: Pronsato, Maria Estela. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de FĂsica del Sur. Universidad Nacional del Sur. Departamento de FĂsica. Instituto de FĂsica del Sur; ArgentinaFil: Brizuela, Graciela Petra. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de FĂsica del Sur. Universidad Nacional del Sur. Departamento de FĂsica. Instituto de FĂsica del Sur; ArgentinaFil: Di Nezio, Maria Susana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de QuĂmica del Sur. Universidad Nacional del Sur. Departamento de QuĂmica. Instituto de QuĂmica del Sur; ArgentinaFil: CenturiĂłn, MarĂa Eugenia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de QuĂmica del Sur. Universidad Nacional del Sur. Departamento de QuĂmica. Instituto de QuĂmica del Sur; Argentin