997 resultados para viscosity solutions


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Dissertação para obtenção do Grau de Mestre em Biotecnologia

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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

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This paper discusses the development of modular solutions for eco low-cost houses based on a pre-fabricated modular wall system environmentally sustainable, socioeconomically competitive and geared towards developing African nations with a housing deficit. The key point to the research of a modular wall solution is a structural layer complemented with local and materials made by non-specialized workforce. This wall also meets also hydrothermal acoustic and mechanical properties. Thus,the solution also offers good safety and interior comfort conditions to its users while maintaining the flexibility to expand the size of the house. Parameters as dimensions, materials and constructive processes of the existing housing stock were studied. Features such as the family size, typology, different uses, common materials, existing regulations, minimal living conditions, safety and comfort have also been considered to achieve the most efficient solution.

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The main objective of the research work developed in the framework of this PhD thesis was the preparation and development of novel photorheological fluids. This was pursued following two distinct strategies. The first one focused on the synthesis of tripodal compounds functionalized with photodimerizable moieties of cinnamic acid, coumarin and anthracene. Two sets of compounds were prepared, varying the central unit as well as spacers resulting in molecules with different solubilities and molecular weight. All compounds were characterized towards their photochemical properties and all exhibited photoreactivity upon irradiation with ultra-violet light. In particular, both coumarin derivatives exhibited the greatest photopolymerization reactivity, resulting in the formation of dendrimeric nanoparticles or in the increase of viscosity of organic solutions. The second strategy was focused on the careful design of photosensitive ionic liquids, based on the results of several quantitative structure-property relationship studies. Thus, photosensitive ionic liquids were synthesized bearing cinnamic acid or coumarin moieties in the organic cation. Upon irradiation, all compounds exhibited reactivity, which resulted in changes in their physical properties, such as melting point or viscosity. In addition, novel coumarin chromophores with different photophysical and photochemical properties were developed. It is expected that these compounds may find application in the preparation of new photosensitive ionic liquids.

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A producer of 5.4 M bbl/d, totalling almost half of the consumption of the entire European Union, the Gulf of Guinea is a fundamental lifeline and maritime link between Europe, the Americas and Africa. Geographically positioned as a staging post for transit originating in Latin America and coupled with its relatively porous borders, the region is also the perfect stepping stone for contraband heading to European shores. While blessed with an enviable wealth of marine and mineral resources, the region is also plagued by an ever-increasing spectre of maritime piracy; accounting for around 30% of incidents in African waters from 2003 to 2011. It is for these reasons that this research centres around the issues of maritime security in the Gulf of Guinea, with a particular focus on the first two decades of the 21st century. This research looks to examine the overall picture of the present state of play in the area, before going on to provide an analysis of potential regional developments in maritime security. This research begins with the analysis of concepts/phenomena that have played a notable role in the shaping of the field of maritime security, namely Globalisation and security issues in the post-Cold War era. The ensuing chapter then focuses in on the Gulf of Guinea and the issues dominating the field of maritime security in the region. The penultimate chapter presents a SWOT analysis, undertaken as part of this research with the aim of correlating opinions from a variety of sectors/professions regarding maritime security in the Gulf of Guinea. The final chapter builds upon the results obtained from the abovementioned SWOT analysis, presenting a series of potential proposals/strategies that can contribute to the field of maritime security in the region over the coming years. This research draws to a close with the presentation of conclusions taken from this particular investigation, as well as a final overview of the earlier presented proposals applicable to the field of maritime security during the second decade of the 21st century.

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NSBE - UNL

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Unilever Food Solutions new digital CRM1 Platform - What is the combination of tools, processes and content that will help Unilever Food Solutions grow his business? Unilever Food Solutions (UFS) intend to create a new online platform to enable it to communicate with segments of the markets, which have previously been too difficult to reach. Specifically targeted at Chefs and other food professionals, the aim is to create an interactive website, which delivers value to its intended users by providing a variety of relevant content and functions, while simultaneously opening up a potential transactional channel to those same users.

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Schizophrenia has long been considered with pessimism, but the recent interest in the early phase of psychotic disorders has modified this often unjustified perception. Literature has demonstrated the benefit of the development of programs specialised in the treatment of early psychosis, which tend to be developed in many countries. It is however important to match them to local needs as well as to the structure of local health services. This paper reviews elements that justify such a development in Lausanne, Switzerland, and describe its various elements.

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Tutkielman tavoitteena oli suunitella markkina-analyysi ja sitä käyttäen määritellä Danzasin Solutions liiketoimintayksikön mahdollisuuksia laajentaa toimintaansa Suomen terveydenhuolto/ lääke- ja elektroniikka/ telekommunikaatiosektoreilla. Danzas Solutions toimisi logistiikkaintegraattorina toimittamalla kokonaisvaltaisia logistisia ratkaisuja. Tutkimus tehtiin haastattelemalla neljää Danzasin asiakasta. Mahdollisimman laajan ja yleistettävän tuloksen saamiseksi haastateltavat valitiin logistiikan ulkoistamisasteeltaan vaihteleviksi. Tutkimus tehtiin ensin tutkimalla sekundääristä informaatiota markkinoilta ja täydentämällä sitä haastatteluista saadulla kvalitatiivisella primääri informaatiolla ja case yrityksen sisäisellä analyysillä. Painopiste tutkimuksessa oli selvittää yritysten ulkoistamiseen ja logistiikkakumppanin valintaan vaikuttavia kriteereitä. Logistiikkaintegraattorille suurimmat mahdollisuudet löytyvät elektroniikka/ telekommunikaatiosektorilta. Logistiikka tällä sektorilla on vaativaa ja yrityksillä ei ole resursseja hallita sitä itse. Terveydenhuolto/ lääkesektorilla yrityksillä on yleensä muut keinot jakeluketjun hallintaan ja ne eivät tarvitse logistiikkaintegraattorin palveluita.

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Ce travail présente une étude de cas post-catastrophe à San Cristobal, Guatemala, où un important glissement de terrain du nom «Los Chorros» (8-10 millions de m3 de roche) affecte depuis 2009 diverses communautés et une des routes principales du pays. Les gestionnaires des risques, sur la base de leur propre évaluation, ont décidé de répondre d'une manière qui ne correspond pas aux intérêts de la population affectée. Les communautés locales ont évalué le risque de catastrophe et ont établi une autre solution suivant une conception du risque différente. Les conflits sociaux et la concurrence entre les différents acteurs du territoire, pour la définition des priorités et des solutions, révèlent les aspects sous-jacents de la société, utiles pour identifier et comprendre ce qui constitue le risque de catastrophe dans un contexte donné. Ce conflit montre que le risque de catastrophe n'est pas univoque mais un concept complexe, constitué par un grand nombre de composants. En termes de gouvernance, il met également en évidence la confrontation des savoirs et la tension qui peut exister entre les différentes approches du risque. Depuis une approche où le risque de catastrophe est considéré comme une construction sociale (les vulnérabilités étant historiquement générées par des processus sociaux, politiques, économiques et culturels), ce travail évalue d'autres modes d'interprétation, de traitement et d'intervention qui peuvent aider à améliorer les méthodes d'évaluation et de gestion des risques. Enfin, la proposition de gestion qui découle de l'exemple guatémaltèque invite à une autre manière de concevoir la gestion des risques en intégrant les différentes conceptions du risque et en visant une coordination stratégique entre les acteurs des politiques publiques, les échelles d'intervention, les experts en charge des différents aléas et la société civile, afin d'obtenir une solution acceptable pour tous les acteurs impliqués dans un territoire. -- This work analyses a post-disaster case study from San Cristobal, Guatemala where a large landslide named "Los Chorros (8 millions cubic meters of rock) affects several communities and one of the country's main west-east access highways. Risk managers, starting from their own assessment, decided to respond in a way that does not correspond to the interests of the afected population. Local communities assessed the risk disaster situation and establised another solution from a different conception of risk. These social conflict and competition for priorities and solutions for risk management reveal that disaster risk is not unequivocal but a complex and holistic concept, constituted by a large set of components. From a social constructivism approach, where disaster risk is considered as the results of social, political, economic and historic process, this thesis evaluates other modes of interpreting, shaping and managing risk that can help improve methods of risk assessment and management. Studying the logic of action of actors, who mobilize to establish a solution, enables to identify as to what constitutes a disaster. For this reason, the study focus, in particular, on the analysis of practices (practical science) implemented by all actors in San Cristobal Altaverapaz. Finally, it puts into perspective the risk management in terms of an integrative approach for policy experts that find compromise between different conceptions of risk in order to obtain a solution acceptable to all those involved.

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This dissertation is based on four articles dealing with modeling of ozonation. The literature part of this considers some models for hydrodynamics in bubble column simulation. A literature review of methods for obtaining mass transfer coefficients is presented. The methods presented to obtain mass transfer are general models and can be applied to any gas-liquid system. Ozonation reaction models and methods for obtaining stoichiometric coefficients and reaction rate coefficients for ozonation reactions are discussed in the final section of the literature part. In the first article, ozone gas-liquid mass transfer into water in a bubble column was investigated for different pH values. A more general method for estimation of mass transfer and Henry’s coefficient was developed from the Beltrán method. The ozone volumetric mass transfer coefficient and the Henry’s coefficient were determined simultaneously by parameter estimation using a nonlinear optimization method. A minor dependence of the Henry’s law constant on pH was detected at the pH range 4 - 9. In the second article, a new method using the axial dispersion model for estimation of ozone self-decomposition kinetics in a semi-batch bubble column reactor was developed. The reaction rate coefficients for literature equations of ozone decomposition and the gas phase dispersion coefficient were estimated and compared with the literature data. The reaction order in the pH range 7-10 with respect to ozone 1.12 and 0.51 the hydroxyl ion were obtained, which is in good agreement with literature. The model parameters were determined by parameter estimation using a nonlinear optimization method. Sensitivity analysis was conducted using object function method to obtain information about the reliability and identifiability of the estimated parameters. In the third article, the reaction rate coefficients and the stoichiometric coefficients in the reaction of ozone with the model component p-nitrophenol were estimated at low pH of water using nonlinear optimization. A novel method for estimation of multireaction model parameters in ozonation was developed. In this method the concentration of unknown intermediate compounds is presented as a residual COD (chemical oxygen demand) calculated from the measured COD and the theoretical COD for the known species. The decomposition rate of p-nitrophenol on the pathway producing hydroquinone was found to be about two times faster than the p-nitrophenol decomposition rate on the pathway producing 4- nitrocatechol. In the fourth article, the reaction kinetics of p-nitrophenol ozonation was studied in a bubble column at pH 2. Using the new reaction kinetic model presented in the previous article, the reaction kinetic parameters, rate coefficients, and stoichiometric coefficients as well as the mass transfer coefficient were estimated with nonlinear estimation. The decomposition rate of pnitrophenol was found to be equal both on the pathway producing hydroquinone and on the path way producing 4-nitrocathecol. Comparison of the rate coefficients with the case at initial pH 5 indicates that the p-nitrophenol degradation producing 4- nitrocathecol is more selective towards molecular ozone than the reaction producing hydroquinone. The identifiability and reliability of the estimated parameters were analyzed with the Marcov chain Monte Carlo (MCMC) method. @All rights reserved. No part of the publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of the author.