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Archivo Digital UPM (90,587 recursos)
This is an institutional repository providing access to the research output of the institution. Primarily contains thesis.

Materia = Química

Mostrando recursos 1 - 11 de 11

1. 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...

2. 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...

3. 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...

4. 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....

5. The aggressiveness of pig slurry to cement mortars - Massana Guitart, Jordi; Guerrero Bustos, Ana; Antón Fuentes, Rebeca; Garcimartin Molina, Miguel Angel; Sanchez Espinosa, Elvira
The aim was to measure the behaviour of various mortars employed in livestock media in central Spain and to analyse the aggressiveness of pig slurry to cement blended with fly ash mortars. To achieve this, mortar specimens were immersed in ponds storing pig slurry. Mortar specimens, of 40 ? 40 ? 160 mm, were made from four types of cement commonly used and recommended for rural areas. The types were a sulphate-resistant Portland cement and three cements blended in different proportions with fly ash and limestone filler. After 3, 6, 12, 24, 36, 48 and 60 months of exposure, three...

6. Propiedades de nanocompuestos de matriz termoestable con nuevos organosilicatos laminares - Calvo del Valle, Silvia; Salom Coll, Catalina; González Prolongo, Margarita; Arribas Arribas, Carmen; García del Cid, A.; Masegosa Fanego, Rosa María
En este trabajo se han preparado nanocompuestos de matriz polímero termoestable del tipo poliéster insaturado y epoxídica utilizando como refuerzo nanosilicatos laminares que se han modificado específicamente para mejorar la interacción con la matriz. En concreto se han modificado montmorillonitas con cationes orgánicos reactivos con la matriz de poliéster insaturado. Asimismo se han silanizado montmorillonitas comerciales orgánicamente modificadas con el objetivo de formar enlaces químicos con la matriz epoxídica. En ambos nanocompuestos se han estudiado las propiedades termo- mecánicas pudiendo comprobar la efectividad de los nuevos organosilicatos.

7. Preliminary approach to neutron instrument selecction at ESSB-Bilbao based on experience at ISIS molecular spectroscopy group - Vicente Bueno, Jesús Pedro de
Collaborative efforts between the Neutronics and Target Design Group at the Instituto de Fusión Nuclear and the Molecular Spectroscopy Group at the ISIS Pulsed Neutron and Muon Source date back to 2012 in the context of the ESS-Bilbao project. The rationale for these joint activities was twofold, namely: to assess the realm of applicability of the low-energy neutron source proposed by ESS-Bilbao - for details; and to explore instrument capabilities for pulsed-neutron techniques in the range 0.05-3 ms, a time range where ESS-Bilbao and ISIS could offer a significant degree of synergy and complementarity. As part of this collaboration, J.P....

8. Advanced Computational Design of Intermediate band Photovoltaic Material V Substituted MgIn2S4 - Aguilera Bonet, Irene; Palacios Clemente, Pablo; Sánchez Noriega, Kefrén; Wahnón Benarroch, Perla
An intermediate-band material based on thiospinel semiconductor MgIn2S4 is presented. This material is proposed as high efficiency photovoltaic material for intermediate-band solar cells. We analyze V substitution for In in the parent compound MgIn2S4 and the formation of the V d-states intermediate band. For the proper characterization of the width and position of this band inside the band gap, the standard one-shot GW method within the plasmon-pole approximation is applied. The electronic properties thus obtained are discussed and compared to those studied with Density Functional Theory (DFT), and the advantages and the limitations of the two methods are discussed. In...

9. Theoretical optoelectronic analysis of MgIn2S4 and CdIn2S4 thiospinels: Effect of transition-metal substitution in intermediate-band formation - Aguilera Bonet, Irene; Palacios Clemente, Pablo; Sánchez Noriega, Kefrén; Wahnón Benarroch, Perla
We analyzed and compared two families of intermediate-band materials derived from indium thiospinels: MgIn2S4, having an inverse spinel structure, and CdIn2S4, a direct spinel. First-principles studies of the electronic structures of these two parent semiconductors were carried out to understand the nature of their band gaps. Optical properties were also analyzed and we found good agreement with experiments. As derivatives of these semiconductors, alloys where transition metals (M=Ti and V) substitute for In atoms at octahedral sites are presented as a class of intermediate-band materials. First, the effect of the substitution on structural parameters is assessed. Then, electronic structures are...

10. Optimización de la eliminación de nutrientes en los circuitos de una depuradora convencional - Castillo González, Isabel del
Esta investigación se basa en reducir los niveles de nutrientes del agua residual, huyendo de los métodos de depuración convencionales, y se lleva a cabo bajo dos vertientes. En la primera se analiza el estado y flujo de los compuestos de nitrógeno y fósforo en siete tipos de depuradoras distintas. La segunda fase se dirige a estudiar sistemas de eliminación de nutrientes por vía química, utilizando sales inorgánicas de hierro y aluminio, polímeros orgánicos y el tratamiento conjunto con oxido de magnesio y ácido fosfórico a ph básico. Estos reactivos se han aplicado a distintas dosis sobre aguas con distintas...

11. Desarrollo de una aplicación a la detección de aromas para una nariz electrónica del tipo microbalanzas de cristal de cuarzo (QCM) para su adaptación a la determinación de calidad de frutas - Correa Hernando, Eva Cristina
Los compuestos aromáticos influyen en el olor de la fruta, siendo responsables de la calidad organoléptica del producto. En este trabajo se ha estudiado la utilidad de un procedimiento instrumental, una nariz electrónica, en la determinación de la calidad aromática de manzanas y peras. Los estudios realizados han permitido establecer que: 1.- La estabilidad y reproducibilidad de la respuesta de los sensores es baja, debido a las perturbaciones externas e internas. 2.- La detección de las distintas fuentes de variación que afectan a la señal registrada por los sensores, permite llevar a cabo un procesado de datos basado en la aplicación...


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