In-situ electron microscopy studies of carbon nanomaterials

High resolution transmission electron microscopy (HRTEM) imaging and electron energy loss spectroscopy (EELS), when conducted in a TEM, are very powerful techniques for studying the structure and composition of nanomaterials at the local scale. Their impact and richness can even been improved if, in parallel, the response of the nanomaterials to an external stimuli is investigated (in situ conditions). During this Final Master Project, these techniques, under in situ conditions, have been developed to investigate two different kind of carbon-based nanomaterials: endohedral functionalized single-walled carbon nanotubes (SW-CNTs) with fullerenes (peapods) and graphene oxide (GO). Electron irradiation in-situ TEM experiments have been carried out on these peapods systems. The evolution of this carbon hybrid nanostructure under electron irradiation has been studied. Experimental results showed that, through the energy applied by electronic irradiation, vacancies were formed in the wall of the nanotube resulting in the reaction with the fullerene and finally forming a nanobud (combination of a SWNT and spherical fullerene).The second system that we have investigated was graphene oxide. We have studied the electrical characteristics and the evolution of the structure and composition of graphene oxide via in situ electrical TEM measurements. To prepare the sample, a dual beam microscope has been employed to deposit the GO flake on a TEM nano-chip. Then, we proceeded with the application of in situ electrical measurements to observe the changes in the GO by taking low loss and core loss EEL spectra. These spectra allow us to study the composition, thickness and sp2 / sp3 of the sample. We have measured the electrical conductivity of GO and the relationship with the reduction and graphizitation of a GO flake.All these in situ TEM works have provided important inputs for the knowledge of these particular carbon nanostructures, their transformation and their properties. Some of these results will have a clear impact on the application of these nanomaterials.<br /

Microemulsions as Nanoreactors to Obtain Bimetallic Nanoparticles

Microemulsions are frequently used as nanoreactors for the synthesis of bimetallic nanoparticles. The ability to manipulate the metal distribution in bimetallic nanoparticles is essential for optimizing applications, and it requires a deeper understanding of how compartmentalization of reaction medium affects nanoparticle synthesis. A simulation model was developed to predict the atomic structure of bimetallic nanoparticles prepared via microemulsion in terms of metals employed and microemulsion composition. The model was successfully proved by comparing theoretical and experimental Au/Pt STEM profiles. On this basis, the model becomes a strong tool to further enhance our knowledge of the complex mechanisms governing reactions in microemulsions and its impact on final nanostructures. The purpose of this study is to perform a comprehensive kinetic analysis of coreduction of different couple of metals in the light of the interplay between three kinetic parameters: intermicellar exchange rate, chemical reduction rates of the two metals, and reactants concentration. The particular combination of these factors determines the reaction rate of each metal, which in turn determines the final metal arrangement

Are the Pyrenees a barrier for the transport of birch (Betula) pollen from Central Europe to the Iberian Peninsula?

This work provides a first assessment of the possible barrier effect of the Pyrenees on the atmospheric transport of airborne pollen from Europe to the North of the Iberian Peninsula. Aerobiological data recorded in three Spanish stations located at the eastern, central and western base of the Pyrenees in the period 2004–2014 have been used to identify the possible long range transport episodes of Betula pollen. The atmospheric transport routes and the origin regions have been established by means of trajectory analysis and a source receptor model. Betula pollen outbreaks were associated with the meteorological scenario characterized by the presence of a high-pressure system overm over Morocco and Southern Iberian Peninsula. France and Central Europe have been identified as the probable source areas of Betula pollen that arrives to Northern Spain. However, the specific source areas are mainly determined by the particular prevailing atmospheric circulation of each location. Finally, the Weather Research and Forecasting model highlighted the effect of the orography on the atmospheric transport patterns, showing paths through the western and easternmost lowlands for Vitoria-Gasteiz and Bellaterra respectively, and the direct impact of air flows over Vielha through the Garona valley.Peer ReviewedPreprin

Analysis of the Utilization of Air-Cooled Blast Furnace Slag as Industrial Waste Aggregates in Self-Compacting Concrete

In this work, the effects of replacing the aggregates of self-compacting concrete by air-cooled blast furnace slag have been analysed. Different mixes have been manufactured by substituting the fine and coarse natural aggregates by air-cooled blast furnace slag. The fracture energy and the tensile and compressive strength have been determined for each mix. The self-compacting properties of the mixes, or the absence of them, have been observed. The main goals of this research are the decrease of the price of aggregates, reduction of the industrial waste, and attenuation the rate of consumption of natural resources. The results show that the self-compactability of the concrete is gradually lost as the slag content is increased, thus, when the ratio of replacement is low, the concrete keeps the self-compacting properties. Nevertheless, the loss of self-compaction affects the mechanical properties by increasing its strength. An air-cooled blast furnace slag did not present problems of heavy metals leaching.Ministerio de Economía y Competitividad BIA2016-75431-RUniversidad de Sevilla VI Plan Propio de Investigació

Análisis de la importación de cemento por vía marítima en España desde finales del siglo XX hasta la actualidad

The main topic of the thesis is the search and obtention of certain tools and criteria which allow us to propose an analytical methodology in order to understand and demonstrate the reasons why Spain has been importing Clinker from so far places as China or Thailand instead of Turkey which should have been the "natural" supplier due to their geographical proximity. Initially we highlighted the next objectives: -To Analyze the capacities and/or logistic limitations of the spanish ports on their cement terminals. -To demonstrate that the import/export capacities of a country go intimately linked to their logistic capacities. -To relate the main cement economic parameters with the import/export capacities of a country. For that: -We have studied the cement history from their begginings together with his Spanish evolution till nowadays. -We have analyzed the freight market from the cement transportation point of view. -We have analyzed the Spanish port cement terminals. -We have issued done freight calculations in order to demonstrate the paramount importance of the ports logistics capacities. Achieving the next conclusions: -The freight value is what determines the global cement movements. The shorter distance does not guarantee the cheapest freight. -It has been demonstrated that the import/export capacites of a country go linked to economical factors, which might be financial or logistics, and the economical level of a country are intimately linked to the cement consumption of the same. -It has been demonstrated that the logistic capacities are the ones determining if a country can import/export to overseas countries, so Spain with her fantastic ports and bulk terminals has been able to receive big vessels from distant countries like China. Also we can confirm: -The cement is a strategical material that big corporations and governments try to control giving rise to an oligopoly. -The value of a ship analyzed as a logistic cost is directly related to the value of the cement. We have standardized a formula to pass from Time charter to a freight par metric ton. -The cost of the low value dry bulk cargoes depends almost exclusively of their logistic cost. -The economy of scale in the cement world does not always apply, due to the fact that in a lot of places we need vessels cranes and grabs to load/discharge which makes totally impossible to use bigger vessels because those are usually gearless.El tema central de la tesis es la búsqueda y la obtención de unas herramientas y/o criterios que permitan proponer una metodología de análisis para entender y demostrar las razones por las que España ha importado Clinker de lugares tan lejanos como China o Tailandia en lugar de Turquía que debería haber sido el suministrador "natural" por cercanía. Inicialmente se marcaron los siguientes objetivos: -Analizar las capacidades y/o limitaciones logísticas de los puertos españoles en sus terminales de cemento. -Demostrar que las capacidades de importación/exportación de un país van íntimamente ligadas a sus capacidades logísticas. -Relacionar las principales magnitudes económicas del mundo del cemento con la capacidad de importación/exportación de un país. Para ello: -Se ha estudiado la historia del cemento desde sus inicios así como su evolución en España hasta la actualidad. -Se han analizado el mercado de fletes desde el punto de vista del transporte del cemento. -Se han analizado las terminales cementeras de los puertos españoles. -Se han realizado cálculos de importes de fletes para demostrar que las capacidades logísticas de los puertos son de importancia capital. Llegando a las siguientes conclusiones: -El valor del flete es el que determina los movimientos de cemento a nivel mundial. La distancia más corta no nos garantiza el flete más barato. -Queda demostrado que la capacidad de importación y exportación de un país va ligada a factores económicos, ya sean logísticos o financieros así como el nivel económico de un país está íntimamente relacionado con el consumo de cemento del mismo. -Ha quedado demostrado que las capacidades logísticas son las que determinan si un país puede importar y/o exportar a países lejanos, ergo España con sus fantásticos puertos y terminales de graneles ha podido recibir buques grandes y por tanto importar de lugares tan lejanos como China. Asimismo, podemos afirmar: -El cemento es un material estratégico que tanto corporaciones como gobiernos intentan controlar y que da por tanto lugar a un oligopolio. -El valor del buque analizado como coste logístico afecta de forma directamente proporcional al valor del cemento. Hemos estandarizado una fórmula para pasar de "Time charter" a flete por tonelada métrica. -El valor de las mercancías a granel de bajo coste depende casi exclusivamente de su coste logístico. -Las economías de escala en el mundo del cemento no siempre son válidas, ya que en muchos lugares hace falta que el propio buque posea medios de carga y/o descarga con lo que pasa a ser inviable el uso de un buque de mayor porte, ya que éstos generalmente carecen de medios propios

Insight into the surface composition of bimetallic nanocatalysts obtained from microemulsions

The enhancement of catalysts efficiency of bimetallic nanoparticles depends on the ability to exert control over surface composition. However, results relating surface composition and feeding solution of bimetallic nanoparticles synthesized in microemulsions are controversial and apparently contradictory. In order to comprehend how the resulting surface can be modified under different synthesis conditions and for different pairs of metals, a computer simulation study was carried out. The resulting surface compositions are explained based on the relative rates of deposition of the two metals, which depend on the particular metal pair, the concentration of reactants and the microemulsion composition. This study provides a satisfactory understanding of experimental results and allows us to identify the main factors affecting the nanoparticle’s surface composition. Consequently, concrete and practical guidelines can be established to facilitate the experimental synthesis of bimetallic nanoparticles with tailored surfacesThis work was supported by Consellería de Cultura, Educación e Ordenación Universitaria, Xunta de Galicia, Spain (Grupos Ref. Comp. ED431C 2017/22; and AEMAT ED431E2018/08), “la Caixa” Foundation-Ref: LCF/PR/PR12/11070003”)S

Soil Microbiome Influences on Seedling Establishment and Growth of Prosopis chilensis and Prosopis tamarugo from Northern Chile

Prosopis chilensis and Prosopis tamarugo, two woody legumes adapted to the arid regions of Chile, have a declining distribution due to the lack of new seedling establishment. This study investigated the potential of both species to establish in soil collected from four locations in Chile, within and outside the species distribution, and to assess the role of the root-colonizing microbiome in seedling establishment and growth. Seedling survival, height, and water potential were measured to assess establishment success and growth. 16S and ITS2 amplicon sequencing was used to characterize the composition of microbial communities from the different soils and to assess the ability of both Prosopis species to recruit bacteria and fungi from the different soils. Both species were established on three of the four soils. P. tamarugo seedlings showed significantly higher survival in foreign soils and maintained significantly higher water potential in Mediterranean soils. Amplicon sequencing showed that the four soils harbored distinct microbial communities. Root-associated microbial composition indicated that P. chilensis preferentially recruited mycorrhizal fungal partners while P. tamarugo recruited abundant bacteria with known salt-protective functions. Our results suggest that a combination of edaphic properties and microbial soil legacy are potential factors mediating the Prosopis establishment success in different soils

Three-dimensional Hypergravity Theories and Semigroup Expansion Method

In this work we present novel and known three-dimensional hypergravity theories which are obtained by applying the powerful semigroup expansion method. We show that the expansion procedure considered here yields a consistent way of coupling different three-dimensional Chern-Simons gravity theories with massless spin-$\frac{5}{2}$ gauge fields. First, by expanding the $\mathfrak{osp}\left(1|4\right)$ superalgebra with a particular semigroup a generalized hyper-Poincar\'e algebra is found. Interestingly, the hyper-Poincar\'e and hyper-Maxwell algebras appear as subalgebras of this generalized hypersymmetry algebra. Then, we show that the generalized hyper-Poincar\'e CS gravity action can be written as a sum of diverse hypergravity CS Lagrangians. We extend our study to a generalized hyper-AdS gravity theory by considering a different semigroup. Both generalized hyperalgebras are then found to be related through an In\"on\"u-Wigner contraction which can be seen as a generalization of the existing vanishing cosmological constant limit between the hyper-AdS and hyper-Poincar\'e gravity theories.Comment: 35 page

Modelo de sistema de vídeo vigilancia con fibra óptica para la municipalidad provincial de Jaén – Cajamarca - Perú

En la presente tesis se desarrolla un modelo de sistema de video vigilancia para la Municipalidad Provincial de Jaén que permita optimizar la seguridad ciudadana en dicha ciudad. En la ciudad de Jaén, la criminalidad y violencia, constituyen en la actualidad un problema social, que exige la necesidad de implementar medidas concretas para disminuir la violencia urbana, en particular contra la delincuencia común, cuyos efectos los padece transversalmente toda la población. El proyecto en referencia contribuye al mantenimiento de la seguridad ciudadana en la Ciudad de Jaén, con el apoyo de la PNP, que tiene a su cargo el mantenimiento del Orden Público, asimismo dicho proyecto considera como componente los medios de comunicación, por lo que la solución que se plantea en el presente estudio, deberá tener la capacidad de integrarlos al sistema de comunicaciones de la PNP, en caso fuera necesario