Agenda de investigación: smart cities y seguridad en Andalucía = Research agenda: smart cities and security in Andalusia, Spain

Smart cities' security governance is a significant challenge that requires careful planning, design, and management. Unfortunately, the number of Andalusian researchers and research groups working on this topic is currently limited, which hinders scientific progress, international competitiveness, and knowledge transfer. To address this issue, this project aims to establish a research agenda to identify the most relevant topics, facilitate resource allocation, and encourage collaboration among researchers, industry, and the public sector. In the near future, effective security management in smart cities will require multidisciplinary approaches that bring together experts from various fields. By promoting coherent initiatives and establishing robust research programs, we can build a strong foundation for sustainable smart cities.P20-00941Security and Global Affair

Catalizadores MnOx-TiO2 para la eliminación de compuestos orgánicos volátiles

Se han sintetizado muestras de Mn-Ti de fórmula general TixMn1-xOy (x = 0, 0.1, 0.2, 0.5, 0.8, 0.9, 1) mediante un método de coprecipitación. Las fases cristalinas mayoritarias identificadas fueron Mn3O4 (hausmanita) y TiO2 (anatasa), formándose también disoluciones sólidas a bajos porcentajes de uno de los cationes. Los materiales son estables térmicamente hasta los 873 K, tranformándose en las fases termodinámicamente estables, TiO2 (rutilo) y a-Mn2O3 a mayores temperaturas. Desde el punto de vista catalítico, son activos en la oxidación de propano y propeno, aunque el aumento del contenido de Ti parece desactivar el óxido de Mn en la oxidación de propileno. Contrariamente, en la oxidación de propano la relación Mn/Ti=1 presenta un máximo en la conversión de propano.Peer reviewe

Estudio FT-IR de la superficie de óxidos mixtos de Fe y Ga mediante la adsorción de moléculas prueba

Several Fe Ga mixed oxide samples denoted as Fe1-xGaxOy (x = 0, 0.20, 0.25, 0.50, 0.80, 0.90) have been synthesised by a conventional coprecipitation method at controlled pH, dried at 90 ºC for 24 hours and calcined at 400 y 800 ºC for 3 hours. All samples were characterised by X-ray diffraction, chemical analyses and thermogravimetry and differential thermal analysis (TG-DTA) and FT-IR and UV-VIS spectroscopies. It was found all materials formed a solid solution, α-(Fe,Ga)2O3, in the entire Fe/Ga compositional range until 400 ºC. Samples calcined at 800 ºC gave rise to biphasic samples for x > 0.5 due to different structure of the β-Ga2O3 with respect to the α-Fe2O3 one. Surface acidity of samples was studied by pivalonitrile molecule adsorption on the pressed pellet of each material, founding weak Lewis acid in all cases and not being possible distinguish both cation sites on the surface and Brönsted one that increased by increasing Ga content. Methanol molecule was also adsorbed, showing an increase of reactivity for those samples with a little bit of Ga content.<br><br>Se han sintetizado varias muestras de óxidos mixtos de Fe y Ga con estequiometría Fe1-xGaxOy (x = 0, 0.20, 0.25, 0.50, 0.80, 0.90) mediante un método convencional de coprecipitación a pH controlado, secado a 90 ºC y calcinación a 400 y 800 ºC durante 3 horas. Todas las muestras se caracterizaron mediante difracción de rayos X, análisis químico, análisis térmicos (TG-ATD), espectroscopías FT-IR y VIS-UV. Se encontró que las muestras formaban una solución sólida α-(Fe,Ga)2O3 en todo el rango de composiciones Fe/Ga hasta 400 ºC, produciéndose muestras bifásicas a partir de 800 ºC para x > 0.50, debido a la distinta estructura de la β-Ga2O3 respecto a la α-Fe2O3. La acidez se estudió mediante la adsorción de pivalonitrilo sobre pastillas prensadas del propio material, observándose acidez tipo Lewis débil no siendo posible distinguir ambos cationes y Brönsted que aumentaba con el contenido de Ga. La adsorción de la molécula de metanol mostró que existe una potenciación de la reactividad cuando se añaden pequeñas cantidades de Ga

A study of Mn-Ti oxide powders and their behaviour in propane oxidation catalysis

Mn-Ti mixed oxides with composition Ti(1-x)Mn(x)O(y) (x =0, 0.1, 0.2, 0.5; 0.8, 0.9 and 1) have been prepared. A Mn-TiO(2) monolayer type sample has also been prepared by impregnation, for comparison. Manganese is found to speed up the anatase-to-rutile phase transition,more clearly in the impregnated sample, while titanium tends to slightly hinder the thermodynamically reversible hausmannite-to-bixbyite phase transition upon cooling; The catalytic activity of all samples in propene oxidation decreases by increasing the Ti content: Conversely, the catalytic activity in propane oxidation shows a maximum at intermediate composition

Catalizadores MnO_x-TiO₂ para la eliminación de compuestos orgánicos volátiles

Mn-Ti mixed oxides with stoichiometry TixMn1-xOy (with x = 0, 0.1, 0.2, 0.5, 0.8, 0.9, 1) have been prepared by a coprecipitation method. Mn3O4 (hausmannite) and TiO2 (anatase) were found to be the main crystalline phases, while solid solutions appeared to be formed at the extreme values of x. Thermal stability of these materials reaches 873 K, transforming into thermodynamically stable phases, TiO2 (rutile) y α-Mn2O3, at higher temperatures. From catalytic point of view, they are active in propane and propene oxidation, though the increase of Ti content seems to deactivate Mn oxide for propene oxidation. Conversely, the sample with the Mn/Ti = 1 ratio presents a maximum for propane oxidation.Se han sintetizado muestras de Mn-Ti de fórmula general TixMn1-xOy (x = 0, 0.1, 0.2, 0.5, 0.8, 0.9, 1) mediante un método de coprecipitación. Las fases cristalinas mayoritarias identificadas fueron Mn3O4 (hausmanita) y TiO2 (anatasa), formándose también disoluciones sólidas a bajos porcentajes de uno de los cationes. Los materiales son estables térmicamente hasta los 873 K, tranformándose en las fases termodinámicamente estables, TiO2 (rutilo) y α-Mn2O3 a mayores temperaturas. Desde el punto de vista catalítico, son activos en la oxidación de propano y propeno, aunque el aumento del contenido de Ti parece desactivar el óxido de Mn en la oxidación de propileno. Contrariamente, en la oxidación de propano la relación Mn/Ti=1 presenta un máximo en la conversión de propano

Heat capacity and magnetocaloric effect in the zircon and scheelite phases of RCrO4, R = Tb, Er, Ho

We present here new magnetization and heat capacity data under magnetic field and direct measurements of the magnetocaloric effect (MCE) in the zircon and the new scheelite phases of RCrO4 (R ​= ​Tb, Er, Ho) from 5 ​K to 100 ​K, for magnetic fields B from 0 to 9 ​T. Zircons have a high MCE near their Curie point, TC ​≃ ​20 ​K, reaching maximum isothermal entropy increments, |ΔST| ​= ​21, 19.4, and 16.2 ​J ​kg−1K−1 for HoCrO4, ErCrO4, and TbCrO4, respectively, for an external field of 5 ​T. TbCrO4 has another anomaly near TD ​= ​60 ​K associated to a Jahn-Teller transition from the tetragonal zircon structure to an orthorhombic phase. Scheelites are antiferromagnetic with TN ​≃ ​25 ​K. In the Tb scheelite the rare earth is strongly coupled to Cr5+ and the MCE exhibits the typical features of an antiferromagnet, i.e. a sort of Curie-Weiss behavior above TN and a sudden drop to small or even inverse values below. In the Er and Ho scheelites the R3+-Cr5+ exchange coupling is very weak and the R3+ ion behaves independently of the Cr5+. As a striking consequence the MCE is quite stronger well below TN.This work has been funded by Spanish MINECO and FEDER (Projects MAT2017-86019-R and MAT2017-84385-R), Gobierno de Aragón (Consolidated Group E100).Peer reviewe

Structural and morphological characterization of Mn-Zr mixed oxides prepared by a sol-gel method

Mn-Zr mixed oxide materials have been prepared by a sol-gel method from a Mn (III) precursor salt and a solution of zirconium acetate in acetic acid, being characterized from a structural and morphological point of view. Conventional solid state techniques show that as obtained powders are formed by mixtures of manganese and zirconium acetates and (hydro) oxides. which evolve to bixbyite, hausmannite, as well as tetragonal and monoclinic Arconia above 873 K. Zirconium enhances the formation of the non-thermodynamically stable manganese compounds instead of the thermodynamically stable ones. This effect was not observed in other samples previously prepared by coprecipitation. In general, mixed systems are thermally stable up to 1073 K due to the formation of a solid solution phase of 10% Mn into zirconia, and display higher specific surface areas than those prepared by the coprecipitation method, Their activities in the combustion of heavy aromatic molecules are hi-her than those of the pure manganese oxides, very likely due to a synergic effect of zirconium. Moreover, the catalytic properties of hausmannite and bixbyite phases for burning this type of hydrocarbons seem to be very similar. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved

A study of coprecipitated Mn-Zr oxides and their behaviour as oxidation catalysts

Mn-Zr mixed oxide samples with the general formula MnxZr1-xOy, where x = 0, 0.1, 0.2, 0.5, 0.8, 0.9, 1, have been prepared by a conventional coprecipitation procedure and characterised by X-ray diffraction (XRD), TG-DTA analyses, FT-IR and UV-VIS-diffuse reflectance (DR-UV-VIS) spectroscopies, BET specific surface measurements and surface acidity by pyridine adsorption techniques. It was found that Mn stabilises the metastable phase tetragonal zirconia and gives rise to low-concentration solid solutions (up to about 10% of Mn), remaining as Mn(IV) within the structure. Their catalytic behaviour was tested by the phenanthrene combustion and the isopropanol oxidation reactions. All samples were found to be active in the total oxidation of phenanthrene at quite a low temperature of 523-673 K. They are also very active in the oxidation of isopropanol, giving rise to acetone with high selectivity at partial conversion and producing CO2 with total selectivity at total conversion. These materials are relevantly more active than Mn-Ti catalysts and approach the activity of pure Mn oxides, but with higher thermal stability. (C) 2001 Elsevier Science B.V. All rights reserved

Is it possible to prepare olivine-type LiFeSiO4?. A joint computational and experimental investigation

Silicates LiMSiO4 are potential positive electrode materials for lithium ion batteries. In this work we analyse from first principles calculations the relative stability of possible LiFeSiO4-polymorphs within four structural types. Olivine-LiFeSiO4 is predicted to be more stable than the LiFeSiO4 prepared by delithiation of Li2FeSiO4; the latter being the only LiFeSiO4 compound reported so far. Attempts to prepare olivine-LiFeSiO4 from a mixture of reactants at ambient pressure (600-1100 °C) resulted in a mixture of quartz-SiO2, Li2SiO3, LiFe5O8 and LiFeSi2O6 phases. Conducting the reaction under HP conditions (40 kbar) leads to the formation of LiFeSi2O6 as a majority phase, regardless the nature of the reactants/precursors. First principles calculations indicate that the preparation of the olivine-LiFeSiO4 is thermodynamically hindered due to the competition with the more stable LiFeSi2O6 pyroxene, in the range of pressure/temperature investigated. © 2008 Elsevier B.V. All rights reserved