Energy optimisation and controllability in complex distillation columns

To extend the knowledge of complex distillation arrangements for the separation of ternary mixtures and make them closer to implementation in industry is the motivation of this thesis work. Some design, operation, and control aspects are analysed, having the conventional distillation arrangements as comparison basis. The DWC is a complex distillation arrangement very attractive in terms of energy and cost savings. However, the DWC require large columns in order to be economically advantageous. Therefore, this arrangement is more attractive when the energy cost is high compared to the trays cost. From rigorous simulations of different separation examples, some synthesis rules have been obtained.Designs that minimise the distillation cost have been given special importance. DWC design procedures reported in the literature were based on only two decision variables. A new procedure that uses three decision variables for design optimisation has been proposed. It has been seen that the use of three decision variables is important to avoid excluding possible optimum designs.The control of the DWC is more complex than the control of the other distillation arrangements because the DWC has more operation degrees of freedom. The approach in this work has been to solve the DWC control by levels: stabilisation, composition control, and optimising control. When the manipulated variables for DWC stabilisation control are the distillate and the bottoms flowrate, which is the most common stabilisation control structure in the literature, the DWC presents high directionality and interaction. Besides, this stabilisation control structure is not appropriate to the DWC because the DWC has typically high reflux ratios. When the manipulated variables for stabilisation control are the reflux flowrate and the boilup, the DWC has better controllability and larger stability margins. Linear analysis tools are useful to select the set of manipulated variables for the DWC composition control. The preferred set of manipulated variables and the controllability of the corresponding control structure depend on the nominal operation. The DWC has two extra operation degrees of freedom that permit an operation optimisation. This optimisation is used to minimise the boilup. At a non-optimal operation, the controllability is improved. Therefore, a trade-off appears between operation optimisation and controllability. Changes in the design of the DWC can be used to improve its controllability. High directionality is a problem associated to DWC that may be improved using a large number of trays. On the other hand, DWC optimal designs have an equilibrated distribution of distillation effort between sections which, if broken, may also present improve the controllability. As found for operation, also for design, leaving optimal conditions permits to improve the controllability. Alternatively, for the composition control of the DWC, Dynamic Matrix Control is analysed. It is found that DMC performs worse than the diagonal feedback control strategy. The DWC extra operation degrees of freedom can be used dynamically for optimising control. Due to a marked directionality found in the response surface, DWC operation may be kept close to optimal operation using only one of the operation degrees of freedom. Optimising control of the DWC through the feedback control of a variable that characterises the optimal operation is possible. Some measurable variables are able to maintain optimal conditions with certain accuracy.The controllability of the DWC is compared to the controllability of other distillation arrangements. In general, the complexity of a distillation arrangement makes its energy efficiency better and its controllability worse. However, important exceptions have been found: - The DWC may give important energy savings as well as the best controllability if it is operated at non-optimal conditions. - When the manipulated variables for stabilisation are internal flows (reflux rates and boilups), the controllability of the DWC is better than the controllability of the other distillation arrangements. The DWC controllability is found to be more interesting for long columns. Therefore, the DWC needs long columns to be really attractive in terms of energy as well as in terms of controllability. In the literature, DWC controllability was misevaluate. In this thesis work, it is seen that, thanks to the arrangement complexity, the DWC may give at the same time energy savings and a good controllability, what makes it very attractive. To know the influence of the non-modelled detail and to obtain experimental results for the DWC is the most important step in the way to DWC implementation in industry

Influència dels hàbits tòxics, estils de vida, condicions ambientals i la vacuna antipneumocòccica en l'aparició de pneumònia adquirida a la comunitat en adults

Consultable des del TDXTítol obtingut de la portada digitalitzadaJustificació: encara que la pneumònia adquirida a la comunitat (PAC) és una malaltia clàssica i àmpliament estudiada, avui dia continua essent una important causa de morbimortalitat i es continua tenint un coneixement limitat dels factors que l'afavoreixen. La PAC es pot considerar una malaltia d'alta incidència, té un maneig clínic controvertit, una mortalitat important (especialment en els vells) i un cost elevat. Si a això s'hi afegeix l'aparició de resistències bacterianes als antibiòtics sembla lògic que en l'abordatge d'aquesta malaltia cada cop prengui més força la perspectiva de la prevenció. Objectius: conèixer els factors de risc d'adquirir una PAC, a la població major de 14 anys, relacionats amb els hàbits tòxics o estils de vida modificables, les condicions ambientals, laborals i de l'ahitatge, així com conèixer l'efecte de la vacuna antipneumocòccica en la prevenció de la PAC en la població major de 14 anys. Metodologia: per donar resposta a aquests objectius es va dissenyar un estudi observacional de tipus cas-control, de base poblacional, multicèntric i coordinat amb una base poblacional de 860.000 persones majors de 14 anys. Aquesta era la població necessària per, en un any, detectar 1.500 casos de PAC. Van participar 64 centres d'atenció primària de Catalunya, Andorra, València i les Illes Balears. Tots els casos de PAC diagnosticats a la població d'estudi durant el període novembre 1999 - novembre 2000 segons uns estrictes criteris clínics, radiològics i evolutius van ser inclosos. Per cada cas es va seleccionar un control aparellat per edat, sexe i centre d'atenció primària segons un procés de mostreig aleatori a partir del padró municipal. A tots ells, se'ls va administrar un extens qüestionari de factors de risc de PAC que feia referència al consum de tabac, alcohol, exposicions laborals, condicions de vida i de l'habitatge, vacunes, així com antecedents mèdics i comorbiditats. Resultats: Durant el període d'estudi es van identificar i reclutar 1.336 casos de PAC (participació 97 %) i 1.326 controls (participació 63 %), amb una edat mitjana de 57 anys i un lleuger predomini del sexe masculí (53 %). La incidència acumulada observada va ser de 1,6 casos/1.000 habitants any amb una clara relació estacional, de manera que la incidència el mes de gener era casi sis vegades superior a la dels mesos de juliol i agost. Pel que fa a la comorbiditat es va observar una associació estadísticament significativa entre la PAC i la infecció respiratòria de vies altes durant l'últim mes, la insuficiència cardíaca, la bronquitis crònica i el càncer, però no amb la diabetis, l'accident vascular cerebral ni la insuficiència renal crònica. Es va observar una associació estadísticament significativa entre el consum de tabac i la PAC independent de les esmentades comorbiditats, així com una relació dosi resposta entre la PAC i la intensitat de l'hàbit, la seva durada i la quantitat total de paquets fumats. Pel que fa al consum passiu de tabac es va observar una important interacció entre aquesta exposició i l'edat, de manera que en les persones de menys de 60 anys el consum passiu de tabac no tenia cap efecte (OR=1,0), mentre que en les de 60 anys o més s'observa un efecte significatiu (OR=1,52) amb una fracció atribuïble poblacional del 10%. En relació al consum d'alcohol es va observar un efecte significatiu només en els homes i quan el consum era superior als 80 g/dia (OR=2,34) sense que s'observi un increment del risc en consums inferiors encara que es facin diàriament. Altres variables associades a la PAC van ser l'exposició laboral a pols (OR=1,65), animals, vísceres o excrements (OR=1,78) i canvis sobtats de temperatura (OR=3,27), conviure més de 10 persones a la llar (OR=2,20), conviure o treballar amb nens de menys de 15 anys (OR=1,48) o tenir animals domèstics (OR=1,37). Les anàlisis multivariades en les que s'ajusta l'efecte de les vacunes per la comorbiditat mostren un efecte protector i estadísticament significatiu tant de la vacuna de la grip (OR=0,76) com de la vacuna antipneumocòccica (OR=0,55). Conclusions: Aquest estudi identifica diversos factors de risc modificables de PAC, el que ha de permetre dissenyar mesures preventives encaminades a disminuir la seva incidència. A més, aporta nova evidència científica sobre l'efectivitat de la vacuna de la grip i la antipneumocòccica en la prevenció de la PAC.Context: Although community-acquired pneumonia (CAP) is a well-known and widely studied disease, morbimortality is high and knowledge of the factors that favor CAP limited. CAP is a disease with high incidence, cost and mortality (especially among the elderly) and disputed clinical management. If to all this one adds antibiotic-resistant bacteria it is hardly surprising that the prevention perspective of the disease is gaining importance. Objectives: to determine the risk factors of acquiring CAP that are related to toxic habits or modifiable lifestyles, environmental, working and living conditions, as well as the effect of the antipneumococcal vaccine in preventing CAP, in a population of over 14 years of age. Methods: A population-based, multicenter, coordinated, observational, case-control study was designed with a population base of 860,000 people of over 14 years of age. This was the population needed to detect 1,500 cases of CAP in one year. Sixty-four primary health care clinics in Catalonia, Andorra, Valencia and the Balearic Islands participated in the study. All cases of CAP, diagnosed according to strict clinical, radiological and evolutional criteria between November 1999 and November 2000, were included in the study. A control matched by age, sex and primary health care clinic was selected for each case, following a random sampling process from the town census. All participants were given a detailed questionnaire on the risk factors of CAP which covered tobacco and alcohol use, occupational exposures, living and housing conditions, vaccines, and medical history and comorbidities. Results: During the study period, 1,336 cases of CAP were identified and enrolled (97% participation) and 1,326 controls were selected (63% participation) with an average age of 57 years and a slight predominance of men (53%). The accumulated incidence observed was of 1.6 cases/1,000 inhabitants/year with a marked seasonal relation reflected by the incidence in January being nearly 6 times greater than the incidence in July or August. With regard to comorbidity, a significant association was found between CAP and upper respiratory infections within the previous month, cardiac insufficiency, chronic bronchitis, and cancer, but not with diabetes, stroke, or chronic renal insufficiency. A significant association was found between smoking and CAP, independent of the above-mentioned comorbidities, and a dose-response relation between CAP and the intensity and duration of the smoking habit and the total number of packets smoked. With regard to passive smoking, a clear interaction between exposure and age was observed, there being no effect on people under 60 years of age (OR=1.0) but a significant effect was observed in people over 60 years (OR=1.52) with a population attributable fraction of 10%. Regarding alcohol consumption, a significant effect was observed for men only and when consumption was greater than 80 g/day (OR=2.34), no increased risk being observed for lower consumption even when daily. Other variables associated with CAP were occupational exposure to dust (OR=1.65), animals, offal, or excrements (OR=3.27) and sharp changes in temperature (OR=3.27), living with more than 10 people in the home (OR=2.20), living or working with children under 15 years of age (OR=1.48), or having pets (OR=1.37). Multivariate analysis where the effect of vaccines was adjusted for comorbidities showed a significant protector effect for both the influenza vaccine (OR=.76) and the antipneumococcal vaccine (OR=.55). Conclusions: This study identified several modifiable risk factors of CAP which should allow preventative measures to be designed to reduce incidence. New scientific evidence on the effectiveness of the influenza and antipneumococcal vaccines in the prevention of CAP has also been presented

Microfluidic synthesis and assembly of reactive polymer beads to form new structured polymer materials

Monodisperse and size-controlled polymer particles were produced without surfactant or wash-coat from O/W monomer emulsions and ‘‘on the fly’’ polymerization under UV irradiation in a very simple needle/tubing system. The effect of the viscosity of the continuous phase on the size of final particles was investigated. The capillary number ratio was found to be relevant to predict the size of the droplets. A relation between dimensionless numbers predicts particle diameter as a function of the needle inner diameter and both velocity and viscosity ratios of continuous and dispersed phases. A functional comonomer was incorporated in the monomer phase so as to obtain polymer microparticles bearing reactive groups on their surface. Polymer beads necklaces were thus formed by linking polymer particles together

Co-axial capillaries microfluidic device for synthesizing size- and morphology-controlled polymer core-polymer shell particles

An easy assembling-disassembling co-axial capillaries microfluidic device was built up for the production of double droplets. Uniform polymer core-polymer shell particles were synthesized by polymerizing the two immiscible monomer phases composing the double droplet. Thus poly(acrylamide) core-poly(tripropylenglycol-diacrylate) shell particles with controlled core diameter and shell thickness were simply obtained by adjusting operating parameters. An empirical law was extracted from experiments to predict core and shell sizes. Additionally uniform and predictable non-spherical polymer objects were also prepared without adding shape-formation procedures in the experimental device. An empirical equation for describing the lengths of rod-like polymer particles is also presented

Modeling a high temperature PEM fuel cell focusing on its thermal behavior

The aim of this work is to develop a Computational Fluids Dynamics model using COMSOL Multiphysics, focusing on the thermal behaviour of a real HT-PEMFC . Energy management is the main concern as a better refrigeration system is needed for the studied system. Using the model simulations at high current conditions can be done without exposing the real stack to temperatures above 180ºC, and therefore, to degradation. Simulations are performed in order to compare different refrigeration designs.Postprint (published version

L'alumnat protagonista de l'aprenentatge pel desenvolupament de competències transversals

Podeu consultar la Vuitena trobada de professorat de Ciències de la Salut completa a: http://hdl.handle.net/2445/66524La siguiente comunicación presenta y analiza la experiencia realizada, en la asignatura de Sociología y Historia de la Actividad Física y el Deporte (6ECTS) del Grado en Ciencias de la Actividad Física y el Deporte, para abordar competencias transversales instrumentales (principalmente: habilidades en la gestión de la información y el manejo de la informática; la toma de decisiones; el conocimiento de idiomas y la comunicación oral y escrita), interpersonales (principalmente: capacidad crítica y autocrítica, trabajo en equipo) y sistémicas (principalmente: habilidades de investigación, capacidad creativa y habilidad para trabajar de forma autónoma). El objetivo principal era mejorar los déficits de nuestros estudiantes reflejados en el estudio sobre la inserción laboral de la población titulada de las universidades catalanas publicado el año 2011 (AQU, 2011). En la experiencia participaron cuatro grupos clase de 40 alumnos..

Análisis del discurso de género en las matrices curriculares de las Ciencias de la Actividad Física y el Deporte

En este trabajo se pretende analizar cómo se ha introducido la perspectiva de género en el currículum universitario, y más específicamente, en el grado de Ciencias de la Actividad Física y el Deporte. Para ello se ha realizado un análisis de contenido y de discurso de 763 guías docentes procedentes de 16 universidades españolas. Los resultados ponen de relevancia como la construcción del conocimiento, y las diversas formas como se puede transmitir conlleva distintas implicaciones para la mayor o menor transformación de las relaciones de género. Las aportaciones de este estudio pueden ser útiles para el diseño de propuestas pedagógicas que pretenden incluir la perspectiva de género y fomentar la transformación social desde la formación universitariaThis paper aims to analyze how gender perspective has been introduced in the higher education curriculum, specifcally in the Physical Activity and Sport Sciences degree. Content analysis and discourse analysis of 763 syllabuses from 16 Spanish public universities were carried out. Findings reveal that construction of knowledge and the several ways it can be conveyed have distinct implications on changing gender relations. The article contributes to the design of new pedagogical proposals that aim to include the gender perspective and promote social changes from higher education.En este trabajo se pretende analizar cómo se ha introducido la perspectiva de género en el currículum universitario, y más específcamente, en el grado de Ciencias de la Actividad Física y el Deporte. Para ello se ha realizado un análisis de contenido y de discurso de 763 guías docentes procedentes de 16 universidades españolas. Los resultados ponen de relevancia como la construcción del conocimiento, y las diversas formas como se puede transmitir conlleva distintas implicaciones para la mayor o menor transformación de las relaciones de género. Las aportaciones de este estudio pueden ser útiles para el diseño de propuestas pedagógicas que pretenden incluir la perspectiva de género y fomentar la transformación social desde la formación universitariaEste trabalho tem como objetivo analisar a introdução da perspectiva de gênero no currículo universitário e, mais especificamente, no grau de Ciências da Atividade Física e do Desporto. Para isso, foi realizada uma análise de conteúdo e discurso de 763 guias de ensino de 16 universidades espanholas. Os resultados mostram como a construção do conhecimento, e as várias maneiras de transmissão trazem implicações diferentes para o grau de transformação das relações de gênero. As contribuições deste estudo podem ser úteis para a concepção de propostas educativas que visam incluir a perspectiva de gênero e promover a transformação social do ensino universitári