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 515
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,...
Heterogeneity of atmosfpheric ammonia at the landscape scale and consequences for environmental impact assessment. - Vogt, Esther; Dragosit, U.; Braban, Christine F.; Theobald, Mark Richard; Dore, Anthony; Van Dikj, N.; Sim Tang, J.; MacDonald, Chris; Murray, Scott; Rees, Robert M.; Sutton, Mark A.
We examined the consequences of the spatial heterogeneity of atmospheric ammonia (NH3) by measuring and modelling NH3 concentrations and deposition at 25 m grid resolution for a rural landscape containing intensive poultry farming, agricultural grassland, woodland and moorland. The emission pattern gave rise to a high spatial variability of modelled mean annual NH3 concentrations and dry deposition. Largest impacts were predicted for woodland patches located within the agricultural area, while larger moorland areas were at low risk, due to atmospheric dispersion, prevailing wind direction and low NH3 background. These high resolution spatial details are lost in national scale estimates at...
Nitrogen deposition alters nitrogen cycling and reduces soil carbon content in low-productivity semiarid Mediterranean ecosystems. - Ochoa Hueso, Raúl; Maestre, Fernando T.; Rios, Asuncion de los; Valea, Sergio; Theobald, Mark Richard; Vivanco, Marta G.; Manrique, Esteban; Bowker, Mathew A.
Anthropogenic N deposition poses a threat to European Mediterranean ecosystems. We combined data from an extant N deposition gradient (4.3–7.3 kg N ha−1 yr−1) from semiarid areas of Spain and a field experiment in central Spain to evaluate N deposition effects on soil fertility, function and cyanobacteria community. Soil organic N did not increase along the extant gradient. Nitrogen fixation decreased along existing and experimental N deposition gradients, a result possibly related to compositional shifts in soil cyanobacteria community. Net ammonification and nitrification (which dominated N-mineralization) were reduced and increased, respectively, by N fertilization, suggesting alterations in the N cycle....
Airplane materials compatibility with blends of fossil kerosene JET A1 with biokerosenes from babassu, palm kernel and coconut oils - Al-lal Baeza, Ana María; Llamas Lois, Alberto; Canoira López, Laureano; Bolonio, David; Sanz-pérez, F; Lapuerta, M
The aviation companies are facing some problems that argue in favor of biofuels: Rising cost of traditional fuel: from 0.71 USD/gallon in May 2003 to 3.09 USD/gallon in January 2012. Environmental concerns: direct emissions from aviation account for about 3 % of the EU’s total greenhouse gas emissions. The International Civil Aviation Organization (ICAO) forecasts that by 2050 they could grow by a further 300-700 %. On December 20th 2006 the European Commission approved a law proposal to include the civil aviation sector in the European market of carbon dioxide emission rights (European Union Emissions Trading System, EUETS)
Aplicación de los sistemas de separación hidráulica y magnética al reciclado de los residuos de construcción y demolición - Rodríguez-Avello Sanz, Ángel; Gómez-Limón , Dulce; Peña Narciso, Christian; Fueyo, Luis
En el presente estudio se analizan las últimas técnicas aplicadas al reciclaje de los residuos de construcción y demolición (RCD), en los que además de los sistemas clásicos de estrio manual y mecánico, trituración y clasificación granulométrica se introducen los equipos de separación hidráulica (clasificadores de banda y tornillos sin fin) y los de pulsación por corriente turbulenta de acción diferencial (Jig). De igual forma los áridos reciclados ganan en calidad cuando se someten a procesos de separación magnética en los cuales las fracciones cerámicas (ladrillos) responden de forma positiva teniendo en cuenta los componentes férricos de las arcillas en...
Bioaccessibility of heavy metals and risk assessment in urban gardens of Madrid - Ortega Romero, Marcelo; Mingot Marcilla, Juan; García Martínez, María Jesús; Miguel García, Eduardo de; Izquierdo, Miguel; Gómez, Amaya
Human health problems and solutions. Urban gardening has spread worldwide in recent years as it enhances food security and selfsupply and promotes community integration. However urban soils are significantly enriched in trace elements relative to background levels. Exposure to the soil in urban gardens may therefore result in adverse health effects depending on the degree of contact during gardening, infant recreational activities and ingestion of vegetables grown in them. In order to evaluate this potential risk, 36 composite samples were collected from the top 20 cm of the soil of 6 urban gardens in Madrid. The aqua regia (pseudototal) and...