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The reinforcement of the ionic conductivity in a lithium-vanadium-molybdenum tellurite glass is possible by modified with zinc oxide {0.7 [x ZnO (1 − x) Li2O] 0.3 [0.5 V2O5. 0.5 MoO3]. 2TeO2}. Structural features induced by zinc cation on the glassy matrix have a positive effect on the electrical behavior of the modified glass. The electrical response of the Zn/Li tellurite glass studied in the present work gives evidence that its ionic conductivity is improved due to the incorporation of small quantities of ZnO suggesting a potential solid ionic electrolyte useful in solid electrochemical devices. Fil: Di Pratula, Pablo Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Terny, Cintia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Sola, Mariela Edith. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

New materials based on V2O5, TeO2 and a combination of graphite, graphene oxide and multiwalled carbon nanotubes were developed and tested as potential electrochemical sensors. A mixture design with three components in combination with multi-response assays based on the desirability function was used as multivariate optimization for the system composition. The optimal sensor contains graphene oxide and multiwalled carbon in approximately equal amounts. The new sensors characterizations were performed with X-ray diffraction, differential scanning calorimetry, impedance spectroscopy and cyclic voltammetry. The main advantage of this electrodes are does not requires surface activation and exhibited a potential electroanalytical performance with different targeted analytes such as ascorbic acid, aspartame and lead. Fil: Pierini, Gastón Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Di Pratula, Pablo Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Ochoa, Ana Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina Fil: Centurión, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Di Nezio, Maria Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

Glasses formed by different oxides are of uppermost importance because they aredeveloped for many applications in electronics, optics, biology, etc. Oxide glasses are built by a three-dimensional network of corner connected oxygen polyhedral that can be modified by the inclusion of other oxides such as transition metal oxides. In this work, the polaron conductivity due to the presence of transition metal oxides in tellurite glasses is analyzed in systems containing alkaline (AO) and alkaline earth oxides (AEO). It is explained how the presence of metal cations (AO or AEO) affects the displacement of the polaron through the network due to the ion-polaron interaction. Fil: Hernandez Garcia, Luis Ancizar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Molina, Magalí Cielo. Universidad Nacional del Sur. Departamento de Química; Argentina Fil: Zoratti, Marianela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Cardillo, Evangelina Cinthia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Terny, Cintia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Sola, Mariela Edith. Universidad Nacional del Sur. Departamento de Química; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

New mixed composite conductors of compositions: Li3V2−x [Cu]x (PO4)3/C and Li3V2−x [Nb]x(PO4)3/C (x = 0.1; 0.2 and 0.3) have been synthesized by the sol-gel method using Citric and Oxalic acids as a primary carbon source and Carbon Black or Carbon Nano-Fibers as secondary carbon sources. The combination of these carbon forms with the Nb doped-polyanion material boosts their electrical behavior up to 10−3 S.m−1 that is two orders of magnitude higher than the Li3V2(PO4)3/C at a room temperature. SEM, TEM and Micro-Raman Spectroscopy evidence that Carbon Nano-Fiber blend is better conductor than Carbon Black blend, which is also revealed by complex conductivity spectra. The conductivity behavior of Nb-doped ceramic is better than the Cudoped one. The obtained niobium composites have a much more stable structure compared to the copper ones because the niobium atoms fit well in the vanadium position, whereas copper atoms are expelled from the structured. Fil: Terny, Cintia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Vega Castillo, Jesus Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; Argentina Fil: de la Rubia, María Ángeles. Centro de Materiales y Dispositivos Avanzados para TIC. Grupo de Propiedades Ópticas, Eléctricas y Magnéticas de Materiales y sus Aplicaciones.; España Fil: de Frutos, José. Centro de Materiales y Dispositivos Avanzados para TIC. Grupo de Propiedades Ópticas, Eléctricas y Magnéticas de Materiales y sus Aplicaciones.; España Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

NiFe2O4 spinel – phosphate (Bi-Ba-Li) glass composite was synthesized by solid-state reaction. New crystalline magnetic phases was developed inside the glassy matrix through a controlled heat treatment. New NF-LBPB4 magnetic nanocomposite material was study. Complex impedance analysis has shown that mobile ions inside the matrix induce the development of complementary crystalline phases resulting in a composite material with excellent magnetic response. An innovative homemade device was designed to test the nanocomposite magnetic response. Fil: Di Pratula, Pablo Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Pistonesi, Carlos Alberto. Universidad Tecnológica Nacional; Argentina Fil: Anton, Marcelo Alejandro. Universidad Tecnológica Nacional; Argentina Fil: Di Prátula, Horacio Raúl. Universidad Tecnológica Nacional; Argentina Fil: Guillermo, Eduardo Daniel. Universidad Tecnológica Nacional; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

[EN] In this work, nitrogen-doped hierarchical porous carbon (NPC) was obtained from an effective and facile synthesis route based on metal-organic framework (MOF)-drive approach using Zr-metal-organic framework (UiO-66-NH2) as a template. The structural analysis of synthesized NPC using different heat treatment was performed through X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and N-2 adsorption-desorption isotherm at 77K characterization. The results achieved indicate that Zr-MOF is an appropriate starting precursor to attain functional carbon materials with remarkable physicochemical properties for potential advanced applications. Thereby, it was evidenced that the NPC synthesis temperature has an influence on resulting structural properties as well as nitrogen functionalities and amount. Thereby, the obtained NPC exhibits a disorder porous structure with high BET surface area (765-867 m(2)/g), pore size from microporous to mesoporous, and 3-4% of N content. Related to nitrogen functionalities, the heteroatom corresponds to quaternary, pyrrolic, and pyridinic bonding, indicating that it was successfully incorporated into the carbon framework., The authors thank Agencia Promotion Nacional de Promocion Cientifica y Tecnologica, Argentina, Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), PICT 2016-0101 Argentina Innovadora, PGI Q24/078 and MAT2017-82288-C2-1-P projects for the financial support.

Performing Molecular Dynamic simulations and using the isoconfigurational ensemble method, we studied the effect of the potassium cation replacing the half part of lithium ions in glassy Li2SiO3. This so-constructed glassy system has the main ingredients present in an immediate forthcoming definition of mixed alkali effect (MAE) in glasses. We show the existence of dynamic correlations among the cations of the same species, i.e. Li–Li and K–K, whereas a very weak correlation was observed between a distinct pair of cations. With this novel approach we can put into evidence that the alkali ion diffusion evolves in specific channels for the ions: a Li ion prefers the lithium ion channel and a K ion prefers the potassium ion channel. This result is coincident with previous simulational studies using the bond–valence technique to reverse Monte Carlo and recent experimental findings using quasielastic neutron scattering. Fil: Balbuena, Cristian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Montani, Ruben Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

A low cost composite electrodes employing tellurite oxide, vanadium oxide and micrometric granular graphite (NWE), were designed as an alternative to be used as working electrode in voltammetry techniques. The synthesis of these composite electrodes is carried out easily; in a short time and their surface not require previous preparation. X-ray diffraction, X-ray fluorescence spectrometry and optical microscopy studies were used to determine the morphology and chemical composition of these electrodes. The conductivity characterization was conducted with impedance and electrochemical measurements. The electrochemical properties of NWE were studied using potassium hexacyanoferrate (II) and ascorbic acid system. Fil: Pierini, Gastón Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Presa, Jimena Mailén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Centurión, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Di Nezio, Maria Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

In this paper, we analyze using differential scanning calorimetry (DSC) how a disordered structure, obtained by the quenching of oxides melted into glass, is related to the nature of the modi- fier cation. We estimated the enthalpy relaxation in based tellurite oxide glasses of formula xM2O (1−x)(0.5 V2 O5 ·0.5MoO3 ) 2TeO2 when they are modified with univalent metal oxides as Na+ , Li+ and Ag+. As ionic conductors in tellurite oxide glasses, these cations have the same charge but different size, electronic configuration and, in addition, their electric behavior is quite different. We show that the jump in the Cp at Tg is also related to the nature of the modifier cation. We study the conventional view of the configurational entropy of liquid that is frozen below the glass transition temperature (Tg) with what is called entropy loss. We explore whether or not there is a relationship between the nature of the modifier oxide and its magnitude. Fil: Cardillo, Evangelina Cinthia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentina Fil: Terny, Cintia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentina

It has been proposed that disk-like micelles may be precursors to the formation of lamellar liquid crystals. The possibility of obtaining n-decane phosphonic acid (DPA) disklike micelles in aqueous solution without the addition of a second ionic surfactant led us to study in detail the low-concentration range of this system by both a battery of experimental techniques and molecular dynamics (MD) simulations. The experimental results indicate that premicelles with some capacity to solubilize dyes are formed at 0.05 mM. The critical micelle concentration (cmc) was found to be 0.260 ± 0.023 mM, much lower than that previously reported in the literature. Spherical micelles, which immediately grow, leading to disk-like micelles, are probably formed at this concentration. At 0.454 ± 0.066 mM, disk-like micelles become unstable, giving rise to the formation of an emulsion of lamellar mesophase that dominates the system beyond 0.670 ± 0.045 mM. These experimental results were corroborated by MD simulations which, additionally, allow describing the structure of the obtained micelles at atomic level. The analysis of the MD trajectories revealed the presence of strong intermolecular hydrogen bonds between the surfactant headgroups, producing a compact polar layer with low water content. The formation of such H-bond network could explain the ability of this surfactant to form disk-like micelles at concentrations close to the cmc. Fil: Schulz, Erica Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentina Fil: Piñeiro, Angel. Universidad de Santiago de Compostela. Departamento de Física Aplicada; España Fil: Rodríguez, José Luis Mariano. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina Fil: Minardi, Rosanna Marina. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentina Fil: Schulz, Pablo Carlos. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina

We study the structure and orientation of water molecules at model hydrophobic surfaces by means of molecular dynamics. We focus here on the role of geometry in water hydration by comparing the situation for a planar graphene sheet with convex surfaces with different curvature: the exterior surfaces of carbon nanotubes and fullerenes of different radii. In all cases, we find the first water hydration layer to be more structured than the bulk. Additionally, the first water layers are found to be well oriented with respect to the surface normal in a way consistent with a local Ice Ih-like structuring, but differently form the water-air interface (along the opposite direction with respect to ice Ih basal plane). We also show that as the curvature of the surface gets more pronounced, the water molecules get less structured and oriented. This monotonic loss of local structure for proximal water represents a smooth tendency whenever we deal with an extended surface. However, when the surface becomes partially or completely non-extended (within the sub-nanometric regime), the surface water layer becomes to quickly lose structuring and orientation. Fil: Alarcon, Laureano Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Malaspina, David Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Schulz, Erica Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Appignanesi, Gustavo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

The aim of the present paper is to give structural information in order to set a correlation between the electrical conductivity behavior and structures of lithium and silver vanadium-tellurite based glasses. We report our structural studies and compare the effect of the nature of the metallic cation on glasses of the form XM2O · (1 - X)V2O5 · 2TeO2 (where 0 ≤ X < 1 and M = Li or Ag). Fourier transform infra-red (FTIR) spectra were recorded for all compositions and complementary differential scanning calorimetry (DSC) measurements and X-ray diffraction (XRD) measurements were also carried out. This paper should be considered as complementary to a previous article reporting the conductive behavior of theses glasses. In the latter we reported the obtained results on electrical conductivity studies. The results confirm the existence of a transition from a typically electronic (polaronic) conductive regimen when the molar fraction (X) of M2O is equal to 0, to an ionic conductive regimen when X tends to 1. The evidence for the independent migration path for both electrons and ions was put into evidence by studying the electrical conductivity behavior in a complementary system of the form X M2O · (1 - X)[0.5V2O5-0.5MoO3] · 2TeO2. In this system vanadium was partially replaced by molybdenum which acts as a 'diluting' agent of the active centers involved in the electronic transport. Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Química; Argentina Fil: Quinzani, Oscar Valentín. Universidad Nacional del Sur. Departamento de Química; Argentina Fil: Pettigrosso, Rosa Susana. Universidad Nacional del Sur. Departamento de Química; Argentina Fil: Villar, Marcelo Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina Fil: Montani, Ruben Alfredo. Universidad Nacional del Sur. Departamento de Química; Argentina

In this work, we assess the relevance of different range particle displacements and string motions to the metabasin (MB) dynamics of a simple glass former. We find that MB transitions are triggered by the occurrence of massive rearrangements termed as "democratic clusters" or d-clusters which last on average less than 1% of the α-relaxation time. Thus, at variance from previous investigations that focused on large displacements and strings, our work points to the essential role of medium-range particle displacements: we find that d-clusters are compact objects since the local neighborhoods of the most mobile particles exhibit significant rearrangements with a clear prevalence of medium-range displacements (of around 20% of the interparticle distance). This is in contrast to the string-like movements for which we demonstrate that many of them fully develop in isolation (their local environment being mostly insensitive to them) and at times different from that of MB transitions, being thus irrelevant to the α-relaxation. Additionally, from the analysis of the MB dynamics, preliminary support to the dynamics facilitation scenario is provided. Fil: Appignanesi, Gustavo Adrian. Universidad Nacional del Sur. Departamento de Química. Laboratorio de Fisicoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina Fil: Frechero, Marisa Alejandra. Universidad Nacional del Sur. Departamento de Química. Laboratorio de Fisicoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Alarcon, Laureano Martin. Universidad Nacional del Sur. Departamento de Química. Laboratorio de Fisicoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

In this paperwe present the study of the glassy systems of formula: xMgO(1−x)(0.5V2O5·0.5MoO3)2TeO2,with (0 b x b 1). The aim of the work is to understand the relationship between in the induced changes in the glassy matrix by the incorporation of MgO in a vanadium–tellurite glass and the electrical response of the material. It has been found that the incorporation of MgO in the glassy matrix raises the glass transition temperature. The whole system's electrical behavior is explained by the small polaron hopping, in good agreement with the variable range polaron hopping model. In this matrix, an ionic transport by Mg2+ is not allowed. The study gives an opportunity to understand how to tune in the middle-range glassy structural order and, as a direct implication, how to control the electrical conduction process., Instituto de Física La Plata

The electrical properties of mixed ion-polaron conducting vanadium tellurite glasses of the form XLi2O·(1 - X)[0.5V2O5·0.5MoO3]2TeO2 have been studied by using the impedance spectroscopy in a wide range of temperature and composition. The obtained results confirm the existence of a transition from a typically electronic (polaronic) conductive regime when the molar fraction (X) of Li2O is equal to 0, to an ionic conductive regime when X tends to 1. This transition is characterised by a deep minimum in the electrical conductivity of about 3 orders of magnitude. The correlated behaviour between conductivity and the mean distance between lithium ions and between vanadium ions reinforces the key idea of two independent migrating paths for both electrons and ions, respectively. Fil: Montani, Ruben Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

The landscape paradigm has become a widespread picture within the realm of complex systems. Complex systems include a great variety of systems, ranging from glasses to biopolymers, which display a common dynamical behavior. Within this framework, the dynamics of a such a system can be envisioned as the search it performs on its (potential energy) landscape. This approach rests on the belief that the relaxation behavior depends only on generic features, irrespective of specific details and lies on the validity of a timescale separation scenario computationally corroborated but not properly validated yet form first principles. In this work we shall show that the prevalence of activated dynamics over other kinds of mechanisms determines the emergence of complex dynamical behavior. Thus, complexity and diversity are not intrinsic properties of a system but depend on the kind of exploration of the landscape. We shall focus mainly on an ample generic context (complex hierarchical systems which have been used as models of glasses, spin glasses and biopolymers) and a specific one (model glass formers). For the last case we shall be able to reveal (in mechanistic terms) the microscopic rationale for the occurrence of timescale separation. Furthermore, we shall explore the connections between these two up to now mostly unrelated contexts and the relation to a variational principle, and we shall reveal the conditions for the applicability of the landscape approach. Fil: Appignanesi, Gustavo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Alarcon, Laureano Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Rodriguez Fris, Jorge Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Montani, Rosana A.. Universidad Nacional del Sur. Departamento de Química; Argentina

In this work, we suggest an explanation of the electrical conductivity behavior of tellurite glassy systems modified with barium when transition metal oxides (V2O5-MoO3) present in the glassy matrix are replaced progressively by barium oxide. These glasses of formula x BaO (1 − x)(0.5 V2O5· 0.5 MoO3)2 TeO2 are obtained by the standard quenching technique and analyzed by means of impedance spectroscopy. We also report some structural results that explain the effect of the bivalent cation (Ba+2) on the electrical response in comparison to the effect of univalent cations on this kind of glassy matrix. The results confirm the existence of a transition from a typical hopping of small polarons response (when the content of BaO is low) to a weak ionic conductive response (when more than 50% of the transition metal oxides content has been replaced by BaO). The independent migration path is suggested by the observed electrical conductivity behavior. In this system, vanadium gives the active centers responsible for the polaron hopping mechanism while barium cations seem to be responsible for the ionic transport regimen. Fil: Terny, Cintia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Cardillo, Evangelina Cinthia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Di Pratula, Pablo Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Villar, Marcelo Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Planta Piloto de Ingeniería Química (I). Grupo Vinculado al Plapiqui - Investigación y Desarrollo en Tecnología Química; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

We compute for an archetypical glass-forming system the excess of particle mobility distributions over the corresponding distribution of dynamic propensity, a quantity that measures the tendency of the particles to be mobile and reflects the local structural constraints. This enables us to demonstrate that, on supercooling, the dynamical trajectory in search for a relaxation event must deal with an increasing confinement of relaxation pathways. This "entropic funnel" of relaxation pathways built upon a restricted set of mobile particles is also made evident from the decay and further collapse of the associated Shannon entropy. Fil: Rodriguez Fris, Jorge Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentina Fil: Appignanesi, Gustavo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentina

Surprisingly, there is not a complete and general working theory for the ionic conduction on structurally disordered inorganic solids at present. In this context, lithium metasilicate glasses appear as paradigmatic and they have been extensively used for investigation in order to identify the main ingredients for a working theory of ionic conducting glasses. In particular among one of these main ingredients, the interaction among the mobile cations appears relevant, especially after recent results showing the existence of preferred pathways for ionic migration. We have performed Molecular Dynamics simulations on lithium metasilicate to better understand the ion-ion interactions. We introduce a very useful tool developed by Harrowell and co-workers (2004) to study propensity to movement and the use of the Pearson´s coefficient to characterize the correlation among the different kinds of ion. Our study allows us to support - from an alternative point of view - the idea of a landscape of energy for lithium ions with high propensity to movement (which eventually belongs to a high propensity cluster as defined in our previous work) and strongly dependent on the interaction among them. On the contrary, in the same window of time, these lithium ions do not strongly correlate with their nearest oxygen ions. Fil: Balbuena, Cristian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentina Fil: Montani, Ruben Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentina

In this paper we present the structural, magnetic and dielectric properties of ceramic nickel manganite NiMn2O4+δ produced by using nickel permanganate Ni(MnO4)2xH2O as a precursor. We have characterized the NiMn2O4+δ stoichiometry using quantitative energy-dispersive analysis of X-rays and thermal gravimetry under reducing conditions. Increased oxygen and Mn4+ contents were detected. X-ray diffraction and Rietveld refinement of X-ray data were carried out. Temperature dependent magnetization measurements were performed and the ferri-magnetic transition was identified at ≈100K. The ferri-magnetic moment was found to be ≈1μB and hysteretic magnetization vs applied field curves were obtained. Dielectric properties were measured using impedance spectroscopy. Two dielectric relaxation processes were detected, which were associated with grain boundary and bulk contributions. The Arrhenius plots of resistivity and the temperature dependent dielectric permittivity were obtained for the two relaxations by means of an equivalent circuit model based on a series of two parallel RC elements. © 2010 Elsevier Ltd. Fil: Díez, Alejandra. Universidad Nacional del Sur. Departamento de Química; Argentina Fil: Schmidt, Rainer. Universidad Complutense de Madrid; España Fil: Sagua, Aurora Estela. Universidad Nacional del Sur. Departamento de Química; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Matesanz, Emilio. Universidad Complutense de Madrid; España Fil: Leon, Carlos. Universidad Complutense de Madrid; España Fil: Morán Emilio, E.. Universidad Complutense de Madrid; España

Supercooled liquids have been shown to be dynamically heterogeneous with different regions of the system presenting dynamics that vary from each other even by orders of magnitude. Computer simulations have confirmed such a picture by detecting that the mobile particles in model glass formers are not homogeneously distributed within the system but arranged in clusters. More recently, the dynamics of small systems has been characterized by demonstrating that their structural relaxation is not homogeneous in time, in the sense that it does not evolve gradually but it is signed by rapid bursts of mobility characterized by relative compact clusters of mobile particles. These events (which have been named d clusters) are fast and sparse and trigger the transitions the system experiences between metabasins (MB) of its potential-energy surface. The MB residence times are much larger than the time scales of occurrence of the d clusters, and it has been suggested that the events that occur within them scarcely contribute to the structural relaxation of the system. Thus, the picture of glassy relaxation that emerges would indicate that at any time a supercooled liquid may present different spatial regions, each one characterized by different structural relaxation times. In turn, each of such regions would not relax smoothly or gradually but by means of sporadic sharp relaxation events. Here, we assess for a model glass former the relative relevance of the MB exploration events and of the d clusters both in small systems and within regions of large systems, to show that the structural relaxation at the region level is indeed extremely heterogeneous in time and utterly governed by the latter. © 2009 The American Physical Society. Fil: Alarcon, Laureano Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur. Departamento de Química; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur. Departamento de Química; Argentina Fil: Montani, Ruben Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur. Departamento de Química; Argentina Fil: Appignanesi, Gustavo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur. Departamento de Química; Argentina