Archivo Digital UPM
This is an institutional repository providing access to the research output of the institution. Primarily contains thesis.
Materia = Química
Mostrando recursos 1 - 20 de 522
Clasificación de zonas en instalaciones para vehículos propulsados por GNC - Lázaro Higuera, Jaime
El presente proyecto tiene como objetivo principal el análisis de la viabilidad de estacionamiento de vehículos propulsados por gas natural comprimido (GNC) desde el punto de vista de formación de atmosferas potencialmente explosivas en los garajes subterráneos. Además se ha realizado una breve introducción sobre el GNC explicando el origen, la composición y los diferentes usos que tiene. Se ha realizado la evaluación de riesgos asociados a la utilización de vehículos propulsados por gas natural y estimación de tasas de escape en el circuito de combustible de los vehículos propulsados por GNC. Para ello se ha aplicado la normativa UNE...
Wettability, polarity and water absorption of Quercus ilex leaves: effect of leaf side and age - Fernandez Fernandez, Victoria; Sancho-Knapik, Domingo; Guzmán Delgado, Paula; Peguero Pina, Jose Javier; Gil Sanchez, Luis; Karabourniotis, George; Khayet, Mohamed; Fasseas, Costas; Heredia-Guerrero, José Alejandro; Heredia, Antonio; Gil Pelegrín, E.
Plant trichomes play important protective functions and may have a major influence on leaf surface wettability. With the aim of gaining insight into trichome structure, composition and function in relation to water-plant surface interactions, we analyzed the adaxial and abaxial leaf surface of Quercus ilex L. (holm oak) as model. By measuring the leaf water potential 24 h after the deposition of water drops on to abaxial and adaxial surfaces, evidence for water penetration through the upper leaf side was gained in young and mature leaves. The structure and chemical composition of the abaxial (always present) and adaxial (occurring only...
Probabilistic meta-analysis of risk from the exposure to Hg in artisanal gold mining communities in Colombia - Miguel García, Eduardo de; Ortega Romero, Marcelo; Gómez San Martín, Amaia; Clavijo, Diana
Colombia is one of the largest per capita mercury polluters in the world as a consequence of its artisanal gold mining activities. The severity of this problem in terms of potential health effects was evaluated by means of a probabilistic risk assessment carried out in the twelve departments (or provinces) in Colombia with the largest gold production. The two exposure pathways included in the risk assessment were inhalation of elemental Hg vapors and ingestion of fish contaminated with methyl mercury. Exposure parameters for the adult population (especially rates of fish consumption) were obtained from nation-wide surveys and concentrations of Hg...
Flammability properties of thermally dried sewage sludge - Fernández Áñez, María de las Nieves; Garcia Torrent, Javier; Medic Pejic, Ljiljana
The treatment and disposal of sewage sludge is becoming an urgent need whereby different technologies were developed and integrated into the waste cycle all over the world. One of the most used technologies is the thermal drying of the sludge. Thermally dried sewage sludge has interesting properties that allow its use as an alternative fuel, but also needs some consideration from the point of view of its safe operation. The aim of this study was the research on the flammability properties of sewage sludge, including ignition sensitivity, explosion severity, thermal sensitivity and thermal stability. Furthermore relationships among those properties and...
Characterization of spontaneous combustuion tendency of dried sewage sludge - Medic Pejic, Ljiljana; Fernández Áñez, María de las Nieves; Montenegro Mateos, Lucía; García Torrent, Javier; Ramírez Gómez, Álvaro
The general purpose of this study was the determination of the safety conditions to avoid the presence of explosive atmospheres in the wastewater industry. Eight Spanish plants located in Madrid, Barcelona and Málaga were considered and several sludge samples were taken in different seasons. The base for the assessment of the spontaneous ignition behaviour of dust accumulations is the experimental determination of the self-ignition temperature under isothermal conditions. Self-ignition temperatures at four volumes were obtained for one sample of sewage sludge, allowing their extrapolation to large storage facilities. A simple test method, based also on an isothermal study of samples,...
Ultrastructure of Plant Leaf Cuticles in relation to Sample Preparation as Observed by Transmission Electron Microscopy - Guzmán Delgado, Paula; Fernandez Fernandez, Victoria; Khayet, Mohamed; García, Maria Luisa; Fernández, Agustín; Gil Sanchez, Luis
The leaf cuticular ultrastructure of some plant species has been examined by transmission electron microscopy (TEM) in only few studies. Attending to the different cuticle layers and inner structure, plant cuticles have been grouped into six general morphological types. With the aim of critically examining the effect of cuticle isolation and preparation for TEM analysis on cuticular ultrastructure, adaxial leaf cuticles of blue-gum eucalypt, grey poplar, and European pear were assessed, following a membrane science approach. The embedding and staining protocols affected the ultrastructure of the cuticles analysed. The solubility parameter, surface tension, and contact angles with water of pure...
From plant surface to plant metabolism: the uncertain fate of foliar-applied nutrients - Fernandez Fernandez, Victoria; Brown, Patrick H.
The application of agrochemical sprays to the aerial parts of crop plants is an important agricultural practice world-wide. While variable effectiveness is often seen in response to foliar treatments, there is abundant evidence showing the beneficial effect of foliar fertilizers in terms of improving the metabolism, quality, and yields of crops. This mini-review is focused on the major bottlenecks associated with the uptake and translocation of foliar-applied nutrient solutions. A better understanding of the complex scenario surrounding the ultimate delivery of foliar-applied nutrients to sink cells and organs is essential for improving the effectiveness and performance of foliar fertilizers.
Molecular Dynamics Simulations of Couette flow - Martín Bautista, Juan A.; Meneghini, Julio; Theofilis, Vassilios
The first steps towards developing a continuum-molecular coupled simulations techniques are presented, for the purpose of computing macroscopic systems of confined fluids. The idea is to compute the interface wall-fluid by Molecular Dynamics simulations, where Lennard-Jones potential (and others) have been employed for the molecular interactions, so the usual non slip boundary condition is not specified. Instead, a shear rate can be imposed at the wall, which allows to obtain the properties of the wall material by means of an iterative method. The remaining fluid region will be computed by a spectral hp method. We present MD simulations of a...
A theoretical study on the formation of iodine oxide aggregates and monohydrates - Fernandez Pacios, Luis; Galvez, O.; Martin, J. C. Gomez; Gomez, P. C.; Saiz-lopez, A.
Biotic and abiotic emissions of molecular iodine and iodocarbons from the sea or the ice surface and the intertidal zone to the coastal/polar marine boundary layer lead to the formation of iodine oxides, which subsequently nucleate forming iodine oxide particles (IOPs). Although the link between coastal iodine emissions and ultrafine aerosol bursts is well established, the details of the nucleation mechanism have not yet been elucidated. In this paper, results of a theoretical study of a range of potentially relevant aggregation reactions of different iodine oxides, as well as complexation with water molecules, are reported. Thermochemical properties of these reactions...
Composición química de extractos de bambú (Guadua angustifolia) - Arrabal Miguel, Carlos; Cortijo Martinez, Manuel; Montoya Arango, J.A.
Se presenta la composición química de los extractos de bambú (Guadua angustifolia). Se realizó un muestreo aleatorio en el Jardín Botánico de la Universidad Tecnológica de Pereira (Colombia) de guaduas maduras y sobremaduras, combinando diafragma, nudo y entrenudo con cepa, basa y sobrebasa, obteniendo un total de 54 muestras. Las muestras se cortaron para obtener discos de unos 2-3 cm de altura, separando nudos, diafragmas y entrenudos. Las muestras trituradas se tamizan y se pesan alícuotas de 3-5 gramos para la extracción. Las extracciones se realizaron por ultrasonidos, con Soxhlet y con extractor Randall con los disolventes éter de petróleo...
Remediation of crude oil contaminated soils by means of bitumen emulsions - Viñas Sánchez, María Teresa; Páez, A.
Effective remediation of contaminated sites with oils, heavy metals and other chemical agents is one of the most important environmental problems all over the world.
Contaminated soils by petroleum from different sites and origins, might contaminate groundwater aquifers and then be spread by rain. Many years and the requirement of
remedial techniques may be needed to remediate them. However, previous experiences show the uselessness of these methods for the solution of all problems. As any case of soil contamination is different, specific studies with relevant factors at financial aspects, legal
limits and waste and soil characteristics are needed. In this work, a study...
Optimization of Pumping System in Solar Pumped Laser. - Peng, Xu; Suhui, Yang; Changming, Zhao; Haiyang, Zhang; Yanlei, Qian; Jiayin, Hao; Tao, He; Wang, Huaxin
The coupling between solar light radiation and laser rod medium in a solar pumped laser affects the efficiency of the laser. To optimize the pumping system, simulation of the two-stage pumping system with a Fresnel lens and conic pumping cavity is carried out with Tracepro software. According to the power density distribution along the axis at focal place of the Fresnel lens, the diameter and position of the pumping cavity window and the distance of the window from the Fresnel lens are optimized. The power density distributions along the laser rod axis of different cavity lengths and different cavity tapers...
Nitrous oxide emissions from European agriculture - an analysis of variability and drivers of emissions from field experiments - Rees, R.M.; Agustín, J.; Alberti, G.; Ball, B.C.; Boeckx, P.; Cantarel, A.; Castaldi, S.; Chirinda, N.; Chojnicki, B.; Giebels, M.; Gordon, H.; Grosz, B.; Horváth, László; Juszczak, R.; Klemedtsson, A. Kasimir; Klemedtsson, L.; Medinets, S.; Machon, A.; Mapanda, F.; Nyamangara, J.; Olesen, J.E.; Reay, D.; Sánchez Martín, Laura; Sanz Cobeña, Alberto; Smith, K.A.; Somerby, A.; Sommer, M.; Soussana, J.F.; Stenberg, M.; Topp, C.F.E.; Van Cleemput, O.; Vallejo García, Antonio; Watson, C.A.; Wuta, M.
Nitrous oxide emissions from a network of agricultural experiments in Europe were used to explore the relative importance of site and management controls of emissions. At each site, a selection of management interventions
were compared within replicated experimental designs in
plot-based experiments. Arable experiments were conducted
at Beano in Italy, El Encin in Spain, Foulum in Denmark,
Logarden in Sweden, Maulde in Belgium
CE1, Paulinenaue in Germany, and Tulloch in the UK. Grassland experiments
were conducted at Crichton, Nafferton and Peaknaze in the
UK, Godollo in Hungary, Rzecin in Poland, Zarnekow in
Germany and Theix in France. Nitrous oxide emissions were
measured at each site over a period of...
Modeling iron-catecholates binding to NGAL protein - Gomez Casado, Cristina; Roth Walter, Franziska; Jensen Jarolim, Erika; Díaz Perales, Araceli; Fernandez Pacios, Luis
Neutrophil gelatinase associated lipocalin (NGAL) protein is attracting a great interest because of its antibacterial properties played upon modulating iron content in competition against iron acquisition processes developed by pathogenic bacteria that bind selective ferric iron chelators (siderophores). Besides its known high affinity to enterobactin, the most important siderophore, it has been recently shown that NGAL is able to bind Fe(III) coordinated by catechols. The selective binding of Fe(III)-catechol ligands to NGAL is here studied by using iron coordination structures with one, two, and three catecholate ligands. By means of a computational approach that consists of B3LYP/6-311G(d,p) quantum calculations for...
CO2 capture by absorption into aqueous tertiary amine solution - Clemente Jul, María del Carmen; Cebamanos, Carlos; Chen, Jian
The aim of this research is to obtain the absorption rate of CO2 into aqueous solution of N,N- di methyl ethanolamine and into aqueous solution of Triethylene diamine and to demonstrate the importance of absorption of CO2 in nowadays by discussing global warming and greenhouse effect. It is also discussed the current situation of China focusing in the latest steps this country has recently made. In the experimental part of this work, the two tertiary amine solutions will absorb CO2 in a Lewis type cell, measuring the pressure change during the reactions take place. The temperature will be between 35...
The potential of organic fertilizers and water management to reduce N2O emissions in Mediterranean climate cropping systems. A review. - Aguilera, Eduardo; Lassaletta, Luis; Sanz Cobeña, Alberto; Garnier, Josette; Vallejo Garcia, Antonio
Environmental problems related to the use of synthetic fertilizers and to organic waste management have led to increased interest in the use of organic materials as an alternative source of nutrients for crops, but this is also associated with N2O emissions. There has been an increasing amount of research into the effects of using different types of fertilization on N2O emissions under Mediterranean climatic conditions, but the findings have sometimes been rather contradictory. Available information also suggests that water management could exert a high influence on N2O emissions. In this context, we have reviewed the current scientific knowledge, including an...
Evaluación del uso de paneles solares como elemento de sombreo en invernaderos - Serrano Burillo, Irene; Muñoz-García, Miguel Angel; Alonso Garcia, M. Carmen; Vela, Nieves
El objetivo principal de este trabajo experimental, es evaluar el uso de paneles solares como opción de elemento de sombreo en viveros, tanto de gran escala como de pequeña superficie. Esta opción podría elegirse tanto en el caso de no disponer de red de suministro eléctrico cercano así como en el caso de preferir no depender de una fuente de energía eléctrica exterior. Como hecho novedoso, se ha elegido paneles solares flexibles de capa fina y poco peso, que serían situados en la cubierta del invernadero. Dicha elección permite que los paneles se adapten a la forma de la cubierta,...