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Los problemas ambientales procedentes del sector de la construcción requieren herramientas que ayuden a frenar el consumo de recursos y el impacto ambiental. El análisis del ciclo de vida (ACV) está reconocido como uno de los métodos más válidos para el análisis ambiental, aunque su aplicación es compleja y es necesaria su estandarización para hacerlo operativo. Building Information Modeling (BIM) se define como un modelo 3D que integra información gráfica y datos sobre los materiales y elementos de un modelo. La integración de ACV en plataformas BIM supone una simplificación en el proceso de evaluación del impacto ambiental. Actualmente es escasa la bibliografía y el desarrollo de herramientas de simulación basadas en modelos BIM-ACV. En esta comunicación se analiza el estado actual de estudios que vinculan modelos BIM con ACV y las metodologías seguidas para realizar la vinculación y la obtención de resultados. Se pondrá de manifiesto la necesidad de estandarizar el ACV implementado en plataformas BIM para simplificar el proceso y obtener resultados de impacto ambiental en tiempo real desde la fase de diseño. Se mostrarán varios casos de estudio realizados en el Máster Universitario en Innovación en Arquitectura: Tecnología y Diseño de la Universidad de Sevilla.

[EN] Nitrogen oxides (NOx) and soot emissions are the most important pollutants from direct-injection diesel engines. In particular, soot formation and oxidation determine the net engine-out soot emissions. These phenomena are complex and competing processes during diesel combustion. Despite many researches implicate the mechanisms of soot formation with soot emissions, the enhancement of the late cycle soot oxidation is the dominant mechanism for a reduction of engine-out soot emissions. The mixing process and the in-cylinder bulk temperature are two important parameters in the development of soot oxidation process. The current research compares different engine strategies to enhance the late cycle mixing controlled combustion process and therefore enhance soot oxidation while maintaining similar gross indicated efficiency in a light-duty engine. For this purpose, a simplified methodology has been used, which analyzes the effect of mixing process and in-cylinder bulk gas temperature on soot oxidation during the late cycle combustion. For carrying out this research, theoretical and experimental tools were used. In particular, the experimental measurements were made in a single-cylinder direct-injection light-duty diesel engine varying the swirl ratio and the injection pattern as injection pressure, Start of Energizing (SoE), Energizing Time (ET) and number of injections events. To analyze soot emissions, the combustion luminosity was measured by an optoelectronic probe and the optical thickness parameter (KL) was evaluated by the two-color pyrometry method. The apparent combustion time (ACT-1) was used as mixing time tracer. Results show that an increase in swirl ratio implies an improvement on the mixing process and higher values of average bulk temperature during the late-cycle diffusion combustion. Both phenomena produce an enhancement in the soot oxidation process. In the lowest swirl ratio case, a suitable injection strategy based on multiple injections, provid

[EN] Recent emission legislation in the marine sector has emphasized the need to reduce nitrogen oxides (NOx) emissions as well as sulphur emissions. The fulfilment of emission legislation limits with conventional marine diesel oil (MDO) requires complex and expensive aftertreatment systems and in this framework lean burn pilot ignited dual fuel (diesel and natural gas) is revealed as one of the most suitable engine platforms to decrease pollutant formations at its source and therefore to mitigate aftertreatment system requirements. For this reason, an experimental study has been carried out in an 8.8 l dual fuel single cylinder Wartsila 20DF engine in order to evaluate different diesel equivalence ratio distributions in the combustion chamber and to get a deeper insight into the interaction between the high reactivity (diesel) and the low reactivity (natural gas) fuels during the ignition process. Engine testing has been complemented with diesel spray pattern simulations for a better understanding of local combustion conditions. Results show the importance of local pilot fuel distribution as a way to control combustion phasing and consequently its impact on combustion instability, emissions and knock conditions. Stable combustion with engine-out NOx levels below legislation have been achieved without the need of after-treatment system using appropriate high reactivity fuel (HRF) distribution control. (C) 2017 Elsevier Ltd. All rights reserved.

Es cada vez más frecuente encontrar en las distintas publicaciones científicas de enfermería trabajos relacionados con su historia y con su representación iconográfica. A lo largo de la historia la actividad cuidadora ha tenido reflejo en numerosas obras de arte, especialmente en aquellas de carácter religioso, concretamente católico. Con este trabajo pretendemos aportar una visión de cómo pueden reflejarse e interpretarse cuidados enfermeros en una colección iconográfica que existe en la Iglesia de San Jorge de Sevilla, sede de la Hermandad de la Santa Caridad. Miguel Mañara pretendió a finales del siglo XVII plasmar mediante la pintura y la escultura los cuidados que había que dispensar a los pobres, basándose en las Siete Obras de Misericordia. Hoy en día, más de 350 años después, vamos a intentar presentar como la metodología actual de cuidados, entronca con estos modelos del siglo XVII, que tenían una base religiosa y caritativa. Mediante un estudio descriptivo y retrospectivo repasaremos la situación social, económica y sanitaria de Sevilla en la centuria del XVII. Conoceremos la obra de Miguel Mañara Vicentelo de Leca al frente de la Hermandad de la Caridad, donde dejó el programa iconográfico motivo de este estudio histórico-etnográfico que, con carácter docente, pretendía dar a conocer las siete obras de misericordia. Es en este programa iconográfico donde desentrañaremos acciones de cuidados de esta centuria que hoy tienen un fundamento metodológico basado en Necesidades y Patrones alterados así como Diagnósticos enfermeros de la taxonomía Nanda.

Reactivity Controlled Compression Ignition (RCCI) is one of the most promising premixed combustion modes, aimed at reducing simultaneously engine emissions and fuel consumption. In this work, the global energy balance (GEB) of a single-cylinder engine operating with dual-fuel and RCCI modes is analysed. The methodology used allows determining the energy degradation from the energy release during the combustion to the final work output, thus evaluating the performance of such combustion mode. The weight of each GEB term is analysed using two references: the injected and the burned fuel energies, thus decoupling the combustion and thermal processes. The analysis is performed by evaluating the effect of some key parameters: low/high reactivity fuel ratio, injection timing and EGR rate. The results show that increasing the low reactivity fuel leads to a better shape of the heat release rate, with a reduction of heat transfer and exhaust losses, thus improving the thermal efficiency about 1% with respect to a conventional Diesel combustion. Injection timing swept shows that a suitable optimization leads to further thermal efficiency increase up to 4%, while EGR has a limited effect. It is also concluded that there is still room for further improvement by reducing incomplete combustion losses.

Reactivity Controlled Compression Ignition concept offers an ultra-low nitrogen oxide and soot emissions with a high thermal efficiency. This work investigates the capabilities of this low temperature combustion concept to work on the whole map of a medium duty engine proposing strategies to solve its main challenges. In this sense, an extension to high loads of the concept without exceeding mechanical stress as well as a mitigation of carbon oxide and unburned hydrocarbons emissions at low load together with a fuel consumption penalty have been identified as main Reactivity Controlled Compression Ignition drawbacks. For this purpose, a single cylinder engine derived from commercial four cylinders medium-duty engine with an adapted compression ratio of 12.75 is used. Commercial 95 octane gasoline was used as a low reactivity fuel and commercial diesel as a high reactivity fuel. Thus, the study consists of two different parts. Firstly, the work is focused on the development and evaluation of an engine map trying to achieve the maximum possible load without exceeding a pressure rise rate of 15 bar/CAD. The second part holds on improving fuel consumption and carbon oxide and unburned hydrocarbons emissions at low load. Results suggest that it is possible to achieve up to 80% of nominal conventional diesel combustion engine load without overpassing the constraints of pressure rise rate (below 15 bar/CAD) and maximum pressure peak (below 190 bar) while obtaining ultra-low levels of nitrogen oxide and soot emissions. Regarding low load challenges, it has developed a particular methodology sweeping the gasoline-diesel blend together with intake temperature or exhaust gas recirculation maintaining constant the combustion phasing and ultra-low nitrogen oxide and soot emissions. As a result a drastic decrease carbon oxide and unburned hydrocarbons emissions is obtained with a slight fuel consumption improvement.

This work investigates the effects of the piston bowl geometry on RCCI (Reactivity Controlled Compression Ignition) heat transfer and combustion losses and its repercussion on the engine efficiency. For this purpose, three piston geometries with compression ratio 14.4:1 have been studied and compared by means of computational modeling. In addition, the engine operating conditions proposed at low, medium and high load were also validated experimentally in a heavy-duty single-cylinder engine adapted for dual fuel operation. The engine speed was kept constant at 1200 rev/min during the research. Results suggest that heat flux through the piston surface represent the major portion of the heat transfer energy. Thus, the comparison of the three geometries demonstrates that reduced piston surface area and reduced charge motion, are the key factors to improve the gross indicated efficiency over the different engine loads. Moreover, it is found that a shallow piston geometry with a smooth transition from the center to the squish region, with a 16% reduced surface area, strongly improves the gross work at low load. However, this gain diminishes due to increased combustion losses as engine load increases. Finally, an intermediate geometry was confirmed as the best balanced piston geometry for RCCI operation over the three different loads.

The present work pursues a twofold objective. On the one hand, the effect of fuel properties on soot formation has been analysed, under different engine operating conditions. On the other hand, sensitivity and performance of the three optical techniques has been evaluated, identifying their main advantages and drawbacks in the framework of the current study. LEM has been considered as the reference technique, as the measurement principle can be implemented without important limitations associated to the other two. Results highlight that larger molecules produce more soot than the smaller ones, with both reactivity and soot formation changing with the proportion of the heavier fraction. Despite describing similar trends, LEM and 2C do not provide the same KL values, with the pyrometry reaching some sort of saturation when increasing flame soot. A detailed analysis confirms that 2-Colar measurements are strongly biased by soot and temperature distribution inside the flame. Nevertheless, it could still be a good option for low sooting conditions. On the other hand, an attempt to calibrate LII signal by means of LEM measurements has been reported. This approach should make it possible to obtain additional information on the soot spatial distribution. However, inconsistencies have been identified which stem from the inherent limitations of LII technique in highly sooting conditions. (c) 2015 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

The more and more stringent emissions regulations, together with the greater fuel economy demanded by vehicle users, impose a clear objective to researchers and engine manufacturers: look for the maximum efficiency with the minimum pollutant emissions levels. The conventional diesel combustion is a highly efficient process, but also leads to high levels of NOx and soot emissions that require using aftertreatment systems to reduce the final levels released to the environment. Since these systems incur in higher costs of acquisition and operation of the engine, the scientific community is working on developing alternative strategies to reduce the generation of these pollutants during the combustion process itself. The literature shows that the new combustion modes based on promoting low temperatures during this process, offer high efficiency and very low NOx and soot levels simultaneously. However, after years of investigation, it can be concluded that these techniques cannot be applied in the whole engine operating range due to, among others, factors like the low control of the combustion process. In recent years, it has been demonstrated that the dual-fuel combustion technique allows to overcome this limitation thanks to the additional degree of freedom provided by the capacity of modulating the fuel reactivity depending on the engine operating conditions. This characteristic, together with the near-zero NOx and soot levels obtained with this technique, has encouraged the scientific community to deeply investigate the dual-fuel combustion. In this sense, former works confirm the advantages previously described, concluding that still exist some limitations to be tackled, as well as some margin for improving the potential of this combustion concept. The general objective of the present Doctoral Thesis is to contribute to the understanding of the dual-fuel combustion mode, with the particular aim of exploring different ways to improve its efficiency. For this purpose, Las cada vez más restrictivas normativas anticontaminantes, junto con la demanda de motores con menor consumo de combustible por parte de los usuarios, imponen un claro objetivo a investigadores y fabricantes de motores: la búsqueda de la máxima eficiencia con los mínimos niveles de emisiones contaminantes. La combustión diésel convencional ofrece una alta eficiencia, pero a su vez da lugar a elevadas emisiones de NOx y hollín que requieren del uso de sistemas de postratamiento para reducir los niveles finales emitidos al ambiente. Dado que estos sistemas incurren en mayores costes de adquisición y operación del motor, la comunidad científica está trabajando en el desarrollo distintas estrategias para reducir la generación de estos contaminantes durante el propio proceso de combustión. La literatura demuestra que los nuevos modos de combustión basados en promover bajas temperaturas durante este proceso, ofrecen simultáneamente una elevada eficiencia y muy bajos niveles de NOx y hollín. Sin embargo, tras años de investigación, se puede llegar a la conclusión de que estas técnicas no pueden ser aplicadas en todo el rango de operación del motor debido a, entre otros, factores como el escaso control sobre el proceso de combustión. En los últimos años, se ha demostrado que la técnica de combustión dual-fuel permite superar esta limitación gracias al grado de libertad adicional que supone la capacidad de modular la reactividad del combustible en función de las condiciones de operación del motor. Esta característica, junto con los casi nulos niveles de NOx y hollín que proporciona, ha despertado un gran interés sobre la comunidad científica. En este sentido, trabajos precedentes confirman las ventajas que este modo de combustión ofrece, demostrando a su vez que aún existen una serie de limitaciones por abordar, así como cierto margen por explotar para mejorar el potencial de este concepto. La presente Tesis Doctoral plantea como objetivo general el contribuir a la comprens, Les cada vegada més restrictives normatives anticontaminants, juntament amb la demanda de motors amb menor consum de combustible per part dels usuaris, imposen un clar objectiu a investigadors i fabricants de motors: la cerca de la màxima eficiència amb els mínims nivells d'emissions contaminants. La combustió dièsel convencional ofereix una alta eficiència, però al seu torn dóna lloc a elevades emissions de NOx i sutge que requereixen de l'ús de sistemes de postractament per a reduir els nivells finals emesos a l'ambient. Aquests sistemes incorren en majors costos d'adquisició i operació del motor, per la qual cosa de forma paral·lela, la comunitat científica està treballant en el desenvolupament de diferents estratègies per a reduir la generació d'aquests contaminants durant el propi procés de combustió. La literatura demostra que les noves tècniques de combustió basades a promoure baixes temperatures durant aquest procés, ofereixen simultàniament una elevada eficiència i molt baixos nivells de NOx i sutge. No obstant açò, després d'anys de recerca, es pot arribar a la conclusió que aquestes tècniques no poden ser aplicades en tot el rang d'operació del motor a causa de, entre uns altres, factors com l'escàs control sobre el procés de combustió. En els últims anys, s'ha demostrat que la tècnica de combustió dual-fuel permet superar aquesta limitació gràcies al grau de llibertat addicional que suposa la capacitat de modular la reactivitat del combustible en funció de les condicions d'operació del motor. Aquesta característica, juntament amb els quasi nuls nivells de NOx i sutge que proporciona, ha despertat un gran interès sobre la comunitat científica. En aquest sentit, treballs precedents confirmen els avantatges que aquesta tècnica de combustió ofereix, demostrant al seu torn que encara existeixen una sèrie de limitacions per abordar, així com cert marge per explotar per a millorar el potencial d'aquest concepte. La present Tesi Doctoral planteja com a objectiu

New combustion modes for internal combustion engines represent one of the main fields of investigation for emissions control in transportation Industry. However, the implementation of lean fuel mixture condition and low temperature combustion in real engines is limited by different unsolved practical issues. To achieve an appropriate combustion phasing and cycle-to-cycle control of the process, the laser plasma ignition system arises as a valid alternative to the traditional electrical spark ignition system. This paper proposes a methodology to set-up and optimize a laser induced plasma ignition system that allows ensuring reliability through the quantification of the system effectiveness in the plasma generation and positional stability, in order to reach optimal ignition performance. For this purpose, experimental tests have been carried out in an optical test rig. At first the system has been optimized in an atmospheric environment, based on the statistical analysis of the plasma records taken with a high speed camera to evaluate the induction effectiveness and consequently regulate and control the system settings. The same optimization method has then been applied under engine-like conditions, analyzing the effect of thermodynamic ambient conditions on the plasma induction success and repeatability, which have shown to depend mainly on ambient density. Once optimized for selected engine conditions, the laser plasma induction system has been used to ignite a direct injection Diesel spray, and to compare the evolution of combustion with that of a conventional auto-ignited Diesel spray.

[ES] Estudio experimental de diferentes mezclas diesel gasolina en un motor de encendido por compresión para la reducción de CO2 de manera conjunta con emisiones de NOx y hollín despreciables. Para ello el alumno realizará trabajo de campo y posteriormente procesará y analizará dichos resultados.

Proyecto confidencial (Riunet)

This work investigates the capabilities of the dual-mode reactivity controlled compression ignition/conventional diesel combustion engine operation to cover the full operating range of a EURO VI medium-duty diesel engine with compression ratio of 17.5:1. This concept is based on covering all the engine map switching between the reactivity controlled compression ignition and the conventional diesel, combustion operating modes. Specifically, the benefits of reactivity controlled compression ignition combustion are exploited whenever possible according to certain restrictions, while the conventional diesel combustion operation is used to cover the zones of the engine map in which the reactivity controlled compression ignition operation is limited. The experiments were conducted using a single-cylinder research diesel engine derived from the multi-cylinder production engine. In addition, considering the mandatory presence of biofuels in the future context of road transport and the ability of ethanol to be blended with gasoline, the low reactivity fuel used in the study is a blend of 20% ethanol by volume with 80% of 95 octane number gasoline. Moreover, a diesel containing 7% of biodiesel has been used as high reactivity fuel. Firstly, a reactivity controlled compression ignition mapping is performed to check the operational limits of the concept in this engine platform. Later, based on the results, the potential of the dual-mode concept is discussed. Results suggest that, under the constraints imposed, reactivity controlled compression ignition combustion can be utilized between 25% and 35% load. In this region of the map, reactivity controlled compression ignition can provide up to 2% increased gross indicated efficiency than conventional diesel combustion, but led to lower efficiency at low engine speeds. In addition, it was demonstrated that the regeneration periods of the diesel particulate filter during dual-mode operation can be reduced more than twice, which enta

Life Cycle Assessment (LCA) is globally recognized as one of the most complete methods for environmental assessment of buildings. Literature assumes that its applications in the building sector are prejudiced regarding complexity and difficulty. However, simplification is necessary, since it can facilitate LCA application in buildings. Moreover, growing interest on reducing environmental impact in the building sector, as well as the relevance of single-family houses on CO2 emissions have become key points on the wide spread of LCA. Therefore, this paper presents a research study about simplification in LCA recent studies applied to singlefamily houses. The review focuses on 20 cases that were analyzed according to ISO 14040, ISO 14044, EN 15978, and EN 15804 standards. The main objective was to identify the simplification strategies assumed in each paper, to clarify and to help to promote further developments on LCA. This paper examines system boundary definition, data sources, life cycle phases included, and environmental impact indicator calculated in case studies. Results show the variety of simplifications identified. They affect physical model definition, life cycle scenario definition and communication of results. In most cases, the functional unit was the complete building, the life cycle scenario definition included production, use and demolition phases, and the most considered environmental impact indicator was GWP. Finally, new challenges and recommendations were defined in order to establish common criteria to develop simplification strategies that allow results comparability in LCA of single-family houses.

During the last decades natural polymers have become more and more frequent to replace traditional inorganic stabilizers in building materials. The purpose of this research is to establish a comparison between the most conventional building material solutions for load-bearing walls and a type of biomaterial. This comparison will focus on load-bearing walls as used in a widespread type of twentieth century dwelling construction in Europe and still used in developing countries nowadays. To carry out this analysis, the structural and thermal insulation characteristics of different construction solutions are balanced. The tool used for this evaluation is the life cycle assessment throughout the whole lifespan of these buildings. This research aims to examine the environmental performance of each material assessed: fired clay brick masonry walls (BW), concrete block masonry walls (CW), and stabilized soil block masonry walls (SW) stabilized with natural fibers and alginates. These conventional and new materials are evaluated from the point of view of both operational and embodied energy.

Como enfoque global, se ha considerado que en la realización del lenguaje cooperan simultáneamente distintos órganos del cuerpo con sus correspondientes funciones; por tanto, el lenguaje es objeto de análisis desde diversas áreas científicas. Lo que nos ha inducido a abordar en nuestro trabajo algunos detalles significativos de distintos ámbitos de estudio. El objetivo principal ha sido analizar por qué la lectura de las noticias, en los medios audiovisuales, difieren ostensiblemente del lenguaje natural. Esa diferencia es percibida no sólo por la extraña entonación y segmentación errada de unidades fonológicas o sintácticas o por la acentuación impropia de palabras átonas, sino también por las diferentes características en los parámetros de la fonación. Para ello era preciso conocer los más importantes mecanismos del lenguaje espontáneo y, a partir de ese conocimiento, examinar qué elementos sufren alteración o desaparecen en el acto de la lectura con respecto al habla natural. La lectura es un acto en el que no intervienen los mecanismos biológicos innatos del ser humano, habitualmente presentes en el habla. En el habla, el pensamiento genera la palabra. Sin embargo, en la lectura, la palabra está ya escrita y por tanto no hay un proceso simultaneo con el pensamiento. Además, el mensaje que recibe el lector a través del grafismo y de los formatos en que se inscriben, constituye un elemento diferenciador del proceso natural. Los indicadores que recibe el lector son: elemento plano del papel y elemento lineal sin curvas de la escritura; formas que se transmiten instintivamente en la fonación. Y aunque en la lectura intervienen los órganos de fonación, no así otros muchos componentes de la movilidad corporal del habla como los brazos, las manos y los músculos del rostro, que son los que dirigen el sentido de la entonación y del ritmo..., As a global approach, it has been considered that in the fulfilment of language different organs of the body with their corresponding functions cooperate simultaneously; therefore language is an object of analysis from different scientific domains. This has led us to address our work using some significant aspects from different fields of study. The main objective has been to analyse why news reading -in audiovisual media- differs ostensibly from natural language. This difference is not only perceived due to the strange intonation and mistaken segmentation of phonologic and syntactic units or due to the inappropriate emphasis of atonic words, but also due to the different characteristics of the phonation parameters. For this, it was necessary to know the most important mechanisms of spontaneous language, and, starting from this knowledge, to examine which elements suffer alteration or disappear in the act of reading with respect to natural speech. Reading is an act in which human innate biological mechanisms –commonly present in speech- do not intervene. In speech, thought generates the word. However, in reading, the word is already written therefore there is no simultaneous process with thought. Besides, the message that the reader receives through the graphic and the format in which it is inscribed, constitute a differentiating element of the natural process. The indicators that the reader receives are: plane element of the paper and the lineal without bends element of writing; forms that are instinctively transmitted in phonation. And even though the phonation organs intervene in reading, they do not do so many components of body mobility of speech such as arms, hands and the muscles of the face, which are the ones that direct the sense of intonation and rhythm...

Already entered in the XXI century "new technologies of information and communication" are hardly "new". Beyond the continuous generation of new technological tools, many more associated with technological dazzle than a real contribution to innovation, there have been few certainties and many promises which, from the advent of Internet in the civilian world, were generated. One of the areas where special Internet has generated excitement has been in the media. In the media field, which is the segment to which we dedicate this research, extreme market liberalization has meant an increasing concentration of media, such as will be discussed at greater length in Chapter IV. According to figures from the Association of Journalists of Chile, 90% of printed newspapers are controlled by two groups; one radio station signals concentrated twenty and 50% of the advertising pie, while increasing arrival of the financial sector to television is observed...

This work evaluates the potential of some new biomass-derived fuels as candidates for compression ignition operation. Thus, fundamental spray characteristics related to fuel vaporization and fuel/air mixing process for 2-Methyltetrahydrofuran, Di-n-butyl ether and 1-octanol has been studied and compared with conventional EN590 Diesel fuel. For this purpose, OH⁄ chemiluminescence and shadowgraphy measurements in a high pressure chamber as well as 1D simulations with a spray model have been carried out at different operating conditions representative of the NEDC driving cycle. Finally, measured soot emissions in the single-cylinder engine were presented and discussed. Results from the high pressure chamber presented very good agreement in terms of liquid length and vapor penetration with simulation results. Thus, some analytical expressions related to macroscopic spray characteristics have been proposed and validated experimentally for all four fuels. Finally, the single-cylinder engine results confirmed the relevant role of soot formation on final emissions for 1-octanol and 2-MTHF. In addition, DNBE showed greater soot oxidation potential than diesel and other TMFB candidates.

This experimental work investigates the effects of piston bowl geometry on RCCI performance and emissions at low, medium and high engine loads. For this purpose three different piston bowl geometries with compression ratio 14.4:1 have been evaluated using single and double injection strategies. The experiments were conducted in a heavy-duty single-cylinder engine adapted for dual fuel operation. All the tests were carried out at 1200 rev/min. Results suggest that piston geometry has great impact on combustion development at low load conditions, more so when single injection strategies are used. It terms of emissions, it was proved that the three geometries enables ultra-low NOx and soot emissions at low and medium load when using double injection strategies. By contrast, unacceptable emissions were measured at high load taking into account EURO VI limitations. Finally, the application of a mathematical function considering certain self-imposed constraints suggested that the more suitable piston geometry for RCCI operation is the stepped one, which has a modified transition from the center to the squish region and reduced piston surface area than the stock geometry.

According to recent studies, the manufacturing and construction of the structural elements of buildings (for example, columns, beams and load-bearing walls) represent the largest proportion of embodied impacts. Some of these reports highlight the need to analyse the materials and techniques used today in order to make the building sector more sustainable. This paper presents the results of embodied energy and global warming potential, using life cycle assessment (LCA) methodology, for load-bearing walls, being these one of the most common types of structures for buildings. This study analyses through an eco-design tool new options for materials used in the construction of structural load-bearing walls. The research aims to examine the environmental performance of each material alternative assessed: fired clay brick masonry (FC), concrete block masonry (CB), reinforced concrete-based wall (RC), and stabilized soil block masonry (SS); stabilized with natural fibers and alginates. These conventional and new materials – especially those with a low level of embodied energy, such as earth blocks – are evaluated from the point of view of their environmental consequences.

El presente subproyecto denominado: “estudio de la influencia del uso del etanol como combustible de baja reactividad en el concepto dual fuel en MEC” se situa dentro de un proyecto nacido de la participación entre el Departamento de Máquinas y Motores Térmicos de la Universitat Politècnica de València con la empresa privada Volvo Trucks, cuyo propósito es disminuir los contaminantes en los motores de encendido por compresión sin reducir la eficiencia de los mismos para cumplir con la normativa de contaminación europea EURO 6. En el presente sub-proyecto se detalla como de forma experimental y través de los ciclos de ensayo según la norma Euro VI; A25, A50 y A75 y usando la estrategia del sistema de inyección “Dual-Fuel” de dos combustibles a bajo régimen, diésel como combustible de alta reactividad y gasolina con varias concentraciones de etanol, se logra una diminución de los contaminantes producidos por la combustión, respetando la normativa vigente (Euro V) y futura (Euro VI), a la vez que se evita la penalización de la eficiencia producida por una normativa de contaminación más estricta y la mejora en el consumo del motor.

This work investigates the effects of the direct injection timing and blending ratio on RCCI performance and engine-out emissions at different engine loads using four low reactivity fuels: E10-95, E10-98, E20-95 and E85 (port fuel injected) and keeping constant the same high reactivity fuel: diesel B7, (direct injected). The experiments were conducted using a heavy-duty single-cylinder research diesel engine adapted for dual-fuel operation. All the tests were carried out at 1200 rpm. To assess the blending ratio effect, the total energy delivered to the cylinder coming from the low reactivity fuel was kept constant for the different fuel blends investigated by adjusting the low reactivity fuel mass as required in each case. In addition, a detailed analysis of the air/fuel mixing process has been developed by means of a 1-D in-house developed spray model. Results suggest that notable higher diesel amount is required to achieve a stable combustion using E85. This fact leads to higher NOx levels and unacceptable ringing intensity. By contrast, EURO VI NOx and soot levels are fulfilled with E20-95, E10-98 and E10-95. Finally, the higher reactivity of E10-95 results in a significant reduction in CO and HC emissions, mainly at low load.

This work investigates the effect of low reactivity fuel characteristics and blending ratio on low load RCCI (reactivity controlled compression ignition) performance and emissions using four different low reactivity fuels: E10-95, E10-98, E20-95 and E85 (port fuel injected) while keeping constant the same high reactivity fuel: diesel B7 (direct injected). The experiments were conducted using a heavy-duty single-cylinder research diesel engine adapted for dual fuel operation. All tests were carried out at 1200 rev/min and constant CA50 of 5 CAD ATDC. For this purpose, the premixed energy was equal for the different blends and the EGR (exhaust gas recirculation) rate was modified as required, keeping constant the rest of engine settings. In addition, a detailed analysis of air/fuel mixing process has been developed by means of a 1-D spray model. Results suggest that in-cylinder fuel reactivity gradients strongly affect the engine efficiency at low load. Specifically, a reduced reactivity gradient allows an improvement of 4.5% in terms of gross indicated efficiency when the proper blending ratio is used. In addition, EURO VI NOx and soot emission levels are fulfilled with a strong reduction in CO and HC compared with the case of the higher reactivity gradient among the low and high reactivity fuel.

The efficiency and CO2 are one of the main concerns of automotive manufacturers. There are several strategies under investigation to solve this problem. In the present work, the research effort has been focused on improving knowledge of in-cylinder heat transfer and its impact on engine efficiency. In particular, soot radiation was studied since it can be considered a significant source of the efficiency losses in modern diesel engines. Considering previous studies, the portion of total chemical energy released during combustion lost due to radiation heat transfer varies widely from 0.5% up to 10%, depending on engine parameters and combustion process. Thus, the main objective of this work was to evaluate the amount of energy lost to soot radiation relative to the input fuel chemical energy during the combustion event under different operating conditions in a completely controlled environment provided by an optical engine. Under these simplified conditions, two-color method was applied by using high speed imaging pyrometer with cameras (two dimensional results) and optoelectronic pyrometer (zero dimensional results). Once a detailed comparison between both diagnostics was performed, optoelectronic pyrometer was used to characterize radiant energy losses in a fully instrumented 4-cylinder direct-injection lightduty diesel engine. In particular swirl ratio, 'EGR and combustion phasing effects on radiation heat transfer were evaluated.

[ES] El objetivo general de este trabajo es el de evaluar de forma cualitativa y cuantitativa el efecto de la ley de combustión en el rendimiento del motor. Con el propósito de clarificar y ordenar el proceso se pueden fijar tres objetivos parciales: 1. Caracterizar el efecto de la ley de combustión en el rendimiento en diferentes condiciones de operación, y seguidamente, identificar y justificar posibles tendencias. 2. Evaluar cómo repercute el cambio de la ley de combustión en otros parámetros de control importantes para el motor, que deben ser controlados y en algunos casos limitados por sus posibles consecuencias. 3. Combinar los objetivos anteriores para explorar el potencial de mejora respecto a las condiciones de referencia, manteniendo una serie de limitaciones desde el punto de vista mecánico, de las emisiones y del ruido en el motor. Estudiar cuál es la influencia de la ley de liberación de calor sobre el rendimiento nos aportará información muy útil sobre posibles formas de optimización del rendimiento en la combustión. Esto puede ser muy interesante para la actual industria automovilística que busca constantemente la máxima eficiencia de sus motores, mediante la reducción del consumo y las emisiones.

Fuel reactivity controlled compression ignition (RCCI) concept has arisen as a solution to control premixed combustion (PCI) strategies, which avoids soot and NOx formation by promoting a lean air fuel mixture and low temperature combustion. Thus, this study is focused on investigating the effects of different engine operating variables over combustion, to be able to suggest suitable strategies for extending the RCCI operation from low to full load, in a HD single-cylinder research engine. Different strategies are implemented at low, medium and high load, varying fuel and air reactivity, by means of parametrical studies. Performance and emissions results are analyzed combining engine testing with 3D-CFD modeling. Based on those results, an overlimit function is used to select the best engine settings for each operating point. Finally, engine emissions and performance results from that RCCI operation are compared with conventional Diesel combustion (CDC). Results suggest that double injection strategies should be used for RCCI operation from low to mid load. However, from high to full load operation, single injection strategies should be used, mainly to avoid excessive in-cylinder pressure gradients. In addition, it is confirmed the suitability of RCCI combustion to overcome the soot NOx trade-off characteristic of CDC, from 6 to 24 bar of BMEP, while improving fuel consumption.

Consulta en la Biblioteca ETSI Industriales (Riunet), [ES] Este primer capítulo consta de cinco partes al margen de esta introducción: marco tecnológico actual, justificación y motivación, características del proyecto, viabilidad y estructura del proyecto. En la primera se hace un recorrido general por el marco tecnológico actual en el sector de los motores de encendido por compresión, así como una breve descripción de cómo se ha llegado a la situación actual. En el segundo apartado se justifica la necesidad de llevar a cabo el presente proyecto mientras que en el tercero se ofrece una breve descripción de las características de este proyecto. El cuarto apartado analiza la viabilidad del proyecto. Por último, en el apartado de estructura del proyecto se describen de una manera general los distintos documentos que van a formar parte de este proyecto.

[EN] The Master Thesis presented here deals with the drawbacks concerning the low combustion efficiency associated to the gasoline PPC and RCCI combustion modes at some engine operating conditions. Despite the fact that both combustion concepts are included into the LTC (Low Temperature Combustion) strategies, this work can be split into two different researches. In the first one, the investigation is focused on evaluating the use of double injection strategies coupled with the spark assistance as a method to improve the engine-out emissions and efficiency on the gasoline PPC combustion mode. In the second one, the work is based on the RCCI low load combustion efficiency optimization while maintaining near zero NOx and soot levels. To carry out this research, both experimental (single cylinder engine, transparent engine, high speed cameras, among others) and theoretical (combustion diagnosis codes, CFD 1D and 3D computational codes) tools have been used, [ES] El presente Trabajo de Fin de Máster aborda la problemática relacionada con la baja eficiencia de combustión que presentan los conceptos de combustión PPC gasolina y RCCI, en determinadas condiciones de operación. Aun encontrándose ambos conceptos de combustión dentro del marco de las estrategias de combustión LTC (Low Temperature Combustion), el trabajo se puede dividir en dos investigaciones diferenciadas. En una primera parte, la investigación se centra en evaluar el uso de estrategias de inyección doble combinadas con la asistencia por bujía como método de mejora sobre las emisiones y eficiencia del concepto de combustión PPC gasolina. En una segunda parte, el trabajo se focaliza en la optimización de la eficiencia de combustión del concepto RCCI en baja carga manteniendo niveles de emisiones de NOx y hollín cercanos a cero. Para ello, se ha combinado tanto el uso de herramientas experimentales (motor monocilíndrico, motor óptico de investigación, cámaras rápidas…) como herramientas teóricas (códigos de diagnóstico de la combustión, herramientas de cálculo computacional CFD 1D y 3D).

This work investigates the potential of RCCI concept to achieve ultra-low NOx and soot emissions over a wide range of engine speed and loads. For this purpose, a detailed experimental methodology has been defined and applied in a heavy-duty single-cylinder engine fueled with diesel and gasoline. In addition, to assess the influence of the engine compression ratio on RCCI capabilities two different compression ratios, 14.4:1 and 11:1, have been tested. Results suggest that a low compression ratio allows to fulfill all the self-imposed constraints (maximum cylinder pressure rise rate of 25 bar/CAD, NOx < 0.4 g/kW h and soot* < 0.01 g/kW h) from idle to full load and engine speeds from 900 to 1800 rpm. However, the use of higher compression ratio requires a delayed injection strategy to avoid excessive knocking levels, which results in unacceptable soot emissions at loads higher than 50%, even when gasoline fractions around 90% are used.

Already entered in the XXI century "new technologies of information and communication" are hardly "new". Beyond the continuous generation of new technological tools, many more associated with technological dazzle than a real contribution to innovation, there have been few certainties and many promises which, from the advent of Internet in the civilian world, were generated. One of the areas where special Internet has generated excitement has been in the media. In the media field, which is the segment to which we dedicate this research, extreme market liberalization has meant an increasing concentration of media, such as will be discussed at greater length in Chapter IV. According to figures from the Association of Journalists of Chile, 90% of printed newspapers are controlled by two groups; one radio station signals concentrated twenty and 50% of the advertising pie, while increasing arrival of the financial sector to television is observed...

Como enfoque global, se ha considerado que en la realización del lenguaje cooperan simultáneamente distintos órganos del cuerpo con sus correspondientes funciones; por tanto, el lenguaje es objeto de análisis desde diversas áreas científicas. Lo que nos ha inducido a abordar en nuestro trabajo algunos detalles significativos de distintos ámbitos de estudio. El objetivo principal ha sido analizar por qué la lectura de las noticias, en los medios audiovisuales, difieren ostensiblemente del lenguaje natural. Esa diferencia es percibida no sólo por la extraña entonación y segmentación errada de unidades fonológicas o sintácticas o por la acentuación impropia de palabras átonas, sino también por las diferentes características en los parámetros de la fonación. Para ello era preciso conocer los más importantes mecanismos del lenguaje espontáneo y, a partir de ese conocimiento, examinar qué elementos sufren alteración o desaparecen en el acto de la lectura con respecto al habla natural. La lectura es un acto en el que no intervienen los mecanismos biológicos innatos del ser humano, habitualmente presentes en el habla. En el habla, el pensamiento genera la palabra. Sin embargo, en la lectura, la palabra está ya escrita y por tanto no hay un proceso simultaneo con el pensamiento. Además, el mensaje que recibe el lector a través del grafismo y de los formatos en que se inscriben, constituye un elemento diferenciador del proceso natural. Los indicadores que recibe el lector son: elemento plano del papel y elemento lineal sin curvas de la escritura; formas que se transmiten instintivamente en la fonación. Y aunque en la lectura intervienen los órganos de fonación, no así otros muchos componentes de la movilidad corporal del habla como los brazos, las manos y los músculos del rostro, que son los que dirigen el sentido de la entonación y del ritmo...