Digital collaborations and entrepreneurship – the role of shareconomy and crowdsourcing in the era of smart city

The thesis begins with the classical cooperation and transfers it to the digital world. This work gives a detailed overview of the young fields of research smart city, shareconomy and crowdsourcing and links these fields with entrepreneurship. The core research aim is the finding of connections between the research fields smart city, shareconomy and crowdsourcing and entrepreneurial activities and the specific fields of application, success factors and conditions for entrepreneurs. The thesis consists of seven peer-reviewed publications. Based on primary and secondary data, the existence of entrepreneurial opportunities in the fields of smart city, shareconomy and crowdsourcing could be confirmed. The first part (publications 1-3) of the thesis are literature reviews to secure the fundamental base for further research. This part consists of newly created definitions and an extreme sharpening of the research fields for the near future. In the second part of the thesis (publications 4-7), empirical field work (in-depth interviews with entrepreneurs) and quantitative analyses (fuzzy set/qualitative comparative analysis and binary logistic regression analysis) contribute to the field of research with additional new insights. Summarizing, the insights are multi-layered: theoretical (e.g. new definitions, sharpening of the research field), methodical (e.g. first time application of the fuzzy set/qualitative comparative analysis in the field of crowdfunding) and qualitative (first time application of in-depth interviews with entrepreneurs in the fields of smart city and shareconomy). The global research question could be answered: the link between entrepreneurship and smart city, shareconomy and crowdfunding could be confirmed, concrete fields of application could be identified and further developments could be touched upon. This work strongly contributes to the young fields of research through much-needed basic work, new qualitative approaches, innovative methods and new insights and offers opportunities for discussion, criticism and support for further research.

O uso da imagiologia por termografia na medicina dentária

Introdução: No domínio científico da medicina dentária, a termografia é um dos temas mais recentes e que tem levado á publicação de alguns estudos. A combinação da avaliação funcional, características de fluxo sanguíneo e localização anatómica levou a um aumento de aplicações da termografia no diagnóstico clínico. Objetivo: Este trabalho teve como objetivo uma analise bibliografia existente sobre a termografia e as suas aplicações em medicina e medicina dentária, avaliar a sua utilidade no diagnóstico de patologias da área de atuação médico-dentária. Metodologia: Procedeu-se a uma pesquisa bibliográfica através da identificação de artigos publicados em bases de dados eletrónicas internacionais, PubMed, B-on e Science Direct utilizando palavras-chave e critérios de exclusão e inclusão, que permitiram fazer uma seleção prévia dos artigos a incluir ao longo deste trabalho. Resultados: Após a realização da pesquisa bibliográfica obtiveram-se 30 artigos. A partir da amostra encontrada foram excluídos 93 artigos devido à falta de correspondência do seu conteúdo ao tema proposto. Conclusão: Os resultados sugerem que a termografia é uma técnica de imagem que deteta a distribuição do calor da superfície corporal. A termografia Capta e transforma a radiação infravermelha emitida pela pele humana em imagens que refletem a dinâmica da microcirculação cutânea. A termografia é considerada como um técnica não invasiva, indolor, não ionizante, fornecendo informações quantitativas que permitem que seja uma técnica válida para o diagnóstico clinico complementar.

Implantes colocados justa cristal versus implantes sub-cristal

Introdução: A posição da colocação do implante relativamente à crista óssea tem sido discutida na comunidade científica como fator influenciador de sucesso ou insucesso. Por outro lado a perda ou preservação óssea está intrinsecamente relacionado com fatores como a seleção do sistema de implante, o tipo de implante e a sua conexão. Objetivo: Este trabalho teve como objetivo a análise da bibliografia existente que compara a colocação de implantes a nível da crista óssea (justa cristal) com a colocação de implantes abaixo da crista óssea (sub-cristal) em sinergismo com outros fatores, de forma que seja percecionada a eficácia e sucesso na seleção efetuada. Metodologia: Procedeu-se a uma pesquisa bibliográfica através da identificação de artigos publicados em bases de dados eletrónicas internacionais, PubMed, B-on e Science Direct utilizando palavras-chave e critérios de exclusão e inclusão, que permitiram fazer uma seleção prévia dos artigos a incluir ao longo deste trabalho. Resultados: Após a realização da pesquisa bibliográfica obtiveram-se 63 artigos. A partir da amostra encontrada foram excluídos 26 artigos devido à falta de correspondência do seu conteúdo ao tema proposto e 14 por se encontrarem repetidos ou sem dados comparativos. Nos 23 artigos aceites encontram-se incluídos estudos animais, elementos finitos, revisões e estudos clínicos. Conclusão: Os resultados sugerem que a colocação de implantes em sub-cristal apresenta-se como uma melhor solução na preservação da crista óssea, no entanto há que levar em conta outros fatores associados diretamente ao implante, nomeadamente, a geometria, superfície não polida do colo assim como o tipo de conexão do pilar ao implante, onde foi encontrada uma relativa evidência de melhor eficácia no que respeita à conexão do tipo “cone Morse”.

Study and investigation of the various reactions of Mazandaran Province shoreline against wind waves

Determining of beach states and study of manner sediment transmission in beach profile, involves the evaluating the actions of hydrodynamic forces dominated over the beaches, in this research through determining the beach states by the help of Hanson and short method, different reactions of Mazandaran’s shoreline against wind waves was studied and investigated. For this reason, First, the kind of hydrodynamic forces dominated over the beaches of this province was studied and beaches of the this province was distinguished as wave–dominated beaches, afterwards eight stations are chosen throughout the shoreline and the waves qualities and the sediments regarding to different depth was evaluated in these stations by using software and laboratory actions. In this way the parameter of dimensionless fall velocity each station was calculated and the beach states and their changes according to time was studied. Finally, the gained information is located in the software area of Arc GIS, and the waves dynamics and the way of erosion and accretion was evaluated in each station. In this research by study of air photographs during a thirty years period we found that was no remarkable changes at shoreline in western and central parts and each type of change depends upon the delta, while eastern part of coast at the location of breakwaters in neighbouring of Farahabad Station, accretion features is quiet evident. In the main results of this research, it became obvious that the beach state in the stations Neca, Farahabad, Larim, Naftchal, Mazandaran university, Babolsar, Noor is dissipative and the beach in Nashtarood station is in intermediate (ridge and runnel) state to the extend that in the dissipation beaches from east to west, the degree of dissipation of the beaches is decreased continuously.

Acessibilidade no ambiente escolar: reflexões com base no estudo de duas escolas municipais de Natal-RN

This work was originated through the results of the analysis of the services for the needs of people with disabilities that were permitted by the physical space of two schools of the municipality of Natal/RN. The general objective/goal was to subsidize the elaboration of alternatives for the planning of environments that could be used by any person. The study used the empirical research through the adoption of a multimethod approach including: (i) technical visits oriented by the NBR 9050, (ii) contact with users that have reduced mobility (visually impaired and wheelchair or crutch users) through escorted travels and interviews, and (iii) interview with school managers. The evidence from the research, even though with significant development of laws that guarantee people with disabilities their right to citizenship, the physical environment of our schools still present with many obstacles that prevent the mobility of people with disabilities which proves their lack of readiness to accommodate them. Therefore, the actions taken to address the accessibility has been the adoption of temporary solutions that makes the adaptation more difficult, adds obstacles and reinforces the undesirable segregation, however still very present in our society. Finally, there is the indication that in order to achieve the spatial configuration that promotes social contact and integration in between the persons with different physical status, it is necessary to completely comprehend the activities developed in each space, from the conception of the equipment to the individual learning needs, having in mind creating environments that stimulates the execution of the tasks in an independent manner without the assistance of others. The inclusion regarding attention to accessibility in the decision making process, directed to the arquitectural and urban project, would decrease the constant need to redevelop and adapt spaces, and should be definitely incorporated as an important component in the production of space

As diretrizes curriculares para a educação ambiental escolar na cidade de Rivera-Uruguai

A pesquisa trás como estudo, investigar “As Diretrizes curriculares para a Educação Ambiental Escolar na cidade de Rivera-Uruguai”; como uma temática que faz parte de meu quefazer pedagógico como docente na rede pública escolar do município de Rivera. Neste sentido, buscando um maior esclarecimento e compreensão de como vem sendo desenvolvida as ações de Educação Ambiental nas escolas públicas riverenses, faz-se necessário realizar uma analise detalhada sobre as diretrizes curriculares uruguaia, e da Educação Ambiental no currículo de educação escolar do Uruguai. E para verificar como estas diretrizes curriculares, e a Educação Ambiental, materializam-se no âmbito da rede pública de ensino escolar riverense; foi importante conhecer a opinião dos educadores riverenses a cerca dos conteúdos destas diretrizes curriculares e da Educação Ambiental; assim como, as estratégias e metodologias utilizadas por estes educadores para viabilizar a tranversalidade da Educação Ambiental nas ações escolares. E o material coletado, e analisado a partir dos princípios da Educação Ambiental na PNEA brasileira, e de alguns pensadores que vem ao encontro deste eixo temático. Nesse âmbito, para se poder obter um maior esclarecimento acerca das ações de Educação Ambiental realizadas no âmbito escolar riverense, utiliza-se como procedimento metodológico a pesquisa qualitativa, com a entrevista semi-estruturada com questionário aberto, realizada aos coordenadores do Departamento do Meio Ambiente a nível nacional e local, e a quatro educadores da rede pública escolar riverense. A análise e interpretação dos dados coletados nos mostram, que apesar de que Educação Ambiental esteja contemplada no currículo escolar como linha transversal, perpassando todas as áreas e campos disciplinares que constitui o programa de educação escolar, nos parâmetros atuais em que se encontra o sistema de ensino uruguaio, fica claro de que a Educação Ambiental remete-se apenas ao ponto de vista ecológico, totalmente desconexa da realidade objetiva e material dos seus sujeitos.

THE FEASIBILITY OF USING WEB-BASED TECHNOLOGY FOR THE MANAGEMENT OF DREDGING PROJECTS

The research investigates the feasibility of using web-based project management systems for dredging. To achieve this objective the research assessed both the positive and negative aspects of using web-based technology for the management of dredging projects. Information gained from literature review and prior investigations of dredging projects revealed that project performance, social, political, technical, and business aspects of the organization were important factors in deciding to use web-based systems for the management of dredging projects. These factors were used to develop the research assumptions. An exploratory case study methodology was used to gather the empirical evidence and perform the analysis. An operational prototype of the system was developed to help evaluate developmental and functional requirements, as well as the influence on performance, and on the organization. The evidence gathered from three case study projects, and from a survey of 31 experts, were used to validate the assumptions. Baselines, representing the assumptions, were created as a reference to assess the responses and qualitative measures. The deviation of the responses was used to evaluate for the analysis. Finally, the conclusions were assessed by validating the assumptions with the evidence, derived from the analysis. The research findings are as follows: 1. The system would help improve project performance. 2. Resistance to implementation may be experienced if the system is implemented. Therefore, resistance to implementation needs to be investigated further and more R&D work is needed in order to advance to the final design and implementation. 3. System may be divided into standalone modules in order to simplify the system and facilitate incremental changes. 4. The QA/QC conceptual approach used by this research needs to be redefined during future R&D to satisfy both owners and contractors. Yin (2009) Case Study Research Design and Methods was used to develop the research approach, design, data collection, and analysis. Markus (1983) Resistance Theory was used during the assumptions definition to predict potential problems to the implementation of web-based project management systems for the dredging industry. Keen (1981) incremental changes and facilitative approach tactics were used as basis to classify solutions, and how to overcome resistance to implementation of the web-based project management system. Davis (1989) Technology Acceptance Model (TAM) was used to assess the solutions needed to overcome the resistances to the implementation of web-base management systems for dredging projects.

Searching for knowledge in the belly of the beast: diversity, social equity and the African graduate student mother's experience in US higher education

Diversity has become a buzz word in public discourse and in educational circles. Higher education institutions in the US have increasingly used this word as a cornerstone of their mission statements and have made increasing efforts to attract students from different backgrounds. As part of the increase in diversity efforts among US colleges, is a significant rise in the number of international students. Attracting international students has become a priority for U.S. universities regardless of size or location. This study examines the intersection between the structure of American educational environment and the blended identities of African Graduate Student Mothers. Within the context of contemporary diversity efforts in US educational institutions, this study examines both the structural environments and the socio-cultural constructs that affect the experiences of African graduate student mothers. Based on a qualitative research interview design, a total of nineteen African graduate student mothers at a Mid-Western University in the US were interviewed individually and in groups over a six weeks period. Results from this study show that apart from the difficult and often dehumanizing treatment African student mothers endure from immigration and consular officials in their various countries and ports of entry, they often find themselves at the margins of their various programs and departments with very little support if any. This is because most of them enroll into graduate programs after arriving as dependants of their spouses; a process that does not allow them to negotiate for departmental commitments and support prior to their arrival. Not only do these women face racial discrimination from white professors, staff and fellow students, but they also experience discrimination and hostilities from African Americans and other minority groups who see them as threats to the limited resources that are often set aside for minority groups in such institutions.

Finding the idea of home

La notion de chez-soi est porteuse d’un imaginaire foisonnant et génère un grand intérêt dans notre culture et société. Bien qu’elle soit une considération importante pour la plupart d’entre nous, l’architecte occupe une position privilégiée qui lui permette d’agir sur le chez-soi de manière significative et tangible. La présente recherche explore le concept du chez-soi tel qu’étudié par les architectes et non-architectes de manière à comprendre son impact sur la création du lieu et sur la construction des environnements domestiques en Amérique du nord. Un regard porté sur les connotations entre espace et lieu, à travers la temporalité, les comportements et les perspectives sociales, supporte l’épistémologie du chez-soi comme un élément important des théories et pratiques de design contemporain. Le démantèlement hypothétique d’un espace en ses composantes suppose que les dispositifs architecturaux peuvent être modelés de manière à ce qu’ils opèrent un transfert depuis la maison, en tant qu’élément physique, vers le domaine psychologique du chez-soi. Afin d’élargir la maniabilité des éléments constitutifs du bâtiment et de son environnement, six thèmes sont appliqués à trois champs de données. Les six thèmes, qui incluent l’entre-deux, la limite, la voie, le nœud, le détail et la représentation, illustrent des moments architecturaux déterminants, potentiellement présents à l’intérieur et à l’extérieur du projet domestique et qui transforment les comportements physiques et psychiques. Depuis la pratique normalisée du logement social et abordable au Canada, une analyse de photographies de maisons abordables existantes, du discours critique sur cette typologie et de projets de recherche-création conduits par des étudiants en architecture, révèle le caractère opérationnel de la notion de chez-soi et consolide les valeurs de communauté et de frontière. L’objectif premier de la recherche est d’avancer la production de connaissances en architecture par l’exploration de la notion de chez­soi dans l’enseignement, la recherche et le design. L’approche fonctionnaliste vis-à-vis le < penser > en design, place l’usager au centre de l’environnement domestique, soutient la proposition que le chez­soi donne sens et utilité au logement, et renforce la responsabilité éthique de l’architecte à faire de cette notion une partie intégrante de la réalité quotidienne.

Da bancada ao Bureau: análise do desenvolvimento da biotecnologia no Nordeste Brasileiro sob o enfoque de Sistema Regional de Inovação

The starting point of the present work consisted of investigating the development of biotechnology in the Northeast region of Brazil from the perspective of a Regional Innovation System (RIS). The theoretical framework adopted relied on the approaches and concepts presented by the Neo-Schumpeterian perspective. This framework was chosen because, by means of the Innovation System concept, this literature allows us to analyze the relationships and configurations of actors, as well as the role of the state and of social, science and technology, and economic policies in the studied region. The analysis considered four selected dimensions: physical infrastructure, human capital, scientific production, and funding. These variables were chosen because they allow us to verify the possibilities and limitations of developing a biotechnology RIS in the Northeast of Brazil, and these elements would help in answering the question behind this dissertation. The location of the physical infrastructure was determined by means of bibliographic and documental research and interviews with heads of institutions that do biotechnology research. Regarding human capital, the analysis focused on resource training in biotechnology, highlighting graduate courses and research groups in the area. To measure knowledge production, we delimited scientific collaboration among researchers in the field of biotechnology as the focus of this category. For the funding dimension, information was gathered from reports available at the websites of national and state funding agencies. The data was analyzed through method triangulation, involving quantitative and qualitative research stages. To back the analyses, we revisited the integration policies in the area of Science, Technology and Innovation. Our analysis has shown that these policies play a crucial role in the development of biotechnology in the region being studied. The data revealed that the physical infrastructure is concentrated in only three states (Bahia, Ceará, and Pernambuco). In this regard, the Northeast Biotechnology Network (Renorbio) stands out as a strategic actor, enabling states with poor infrastructure to develop research through partnerships with institutions located in another state. We have also verified that the practices involving human resource training and knowledge production are factors that enable the emergence of a regional system for biotechnology in the studied region. As limitations, we have verified the low immersion level of regional actors, the heterogeneity of socioeconomic indicators, the lack of financial resources, and a low innovation culture in the business sector. Overall, we have concluded that the development of a Regional Innovation System in Biotechnology, based on the current regional dynamics, depends on an effective change in the behavior of the social agents involved, both in the national and regional dimensions as well as in the public and private spheres

Physiological Effects of Alcohol on Crayfish Escape Circuitry

Alcohol is one of the oldest and most widely used drugs on the planet, but the cellular mechanisms by which it affects neural function are still poorly understood. Unlike other drugs of abuse, alcohol has no specific receptor in the nervous system, but is believed to operate through GABAergic and serotonergic neurotransmitter systems. Invertebrate models offer circuits of reduced numerical complexity and involve the same cell types and neurotransmitter systems as vertebrate circuits. The well-understood neural circuits controlling crayfish escape behavior offer neurons that are modulated by GABAergic inhibition, thus making tail-flip circuitry an effective circuit model to study the cellular mechanisms of acute alcohol exposure. Crayfish are capable of two stereotyped, reflexive escape behaviors known as tail-flips that are controlled by two different pairs of giant interneurons, the lateral giants (LG) and the medial giants (MG). The LG circuit has been an established model in the neuroscience field for more than 60 years and is almost completely mapped out. In contrast, the MG is still poorly understood, but has important behavioral implications in social behavior and value-based decision making. In this dissertation, I show that both crayfish tail-flip circuitry are physiologically sensitive to relevant alcohol concentrations and that this sensitivity is observable on the single cell level. I also show that this ethyl alcohol (EtOH) sensitivity in the LG can be changed by altering the crayfish’s recent social experience and by removing descending inputs to the LG. While the MG exhibits similar physiological sensitivity, its inhibitory properties have never been studied before this research. Through the use of electrophysiological and pharmacological techniques, I show that the MG exhibits many similar inhibitory properties as the LG that appear to be the result of GABA-mediated chloride currents. Finally, I present evidence that the EtOH-induced changes in the MG are blocked through pre-treatment of the potent GABAA receptor agonist, muscimol, which underlines the role of GABA in EtOH’s effects on crayfish tail-flip circuitry. The work presented here opens the way for crayfish tail-flip circuitry to be used as an effective model for EtOH’s acute effects on aggression and value-based decision making.

A Gestão de Recursos Humanos na Guarda Nacional Republicana e o Empenhamento Organizacional

Considerada um dos elementos basilares para uma cabal e completa prossecução dos objetivos das instituições, a avaliação de desempenho permite valorizar o elemento distintivo das organizações, o ser humano. É neste contexto holístico, centrado na necessidade objetiva de incrementar o empenhamento organizacional, que a Guarda Nacional Republicana procura, através da aplicação do seu Regulamento de Avaliação de Mérito, avaliar o desempenho dos seus militares, no sentido de verificar em que medida estes contribuem para os fins últimos definidos para a instituição. Deste modo, torna-se evidente a importância de, concomitantemente, investigar de que forma este sistema de avaliação é aceite, interiorizado e percebido pelos militares da instituição e compreender se esse sistema de avaliação se assume como uma mais-valia objetiva na promoção do empenho operacional, permitindo o desenvolvimento da carreira dos mais capazes e orientados para a tarefa institucional. Assim, considerando a unicidade que se encontra adjudicada à categoria profissional de Oficiais, únicos elementos do sistema avaliativo que são, cumulativamente, avaliados e avaliadores, a presente pesquisa, através da aplicação de um questionário a uma amostra de 294 Oficiais, procura saber qual é a representação social que estes têm do sistema de avaliação em vigor na Guarda Nacional Republicana. Abstract: Seen as an essential element for a complete and exact prosecution of the institution’s aims, the evaluation of the performance allows the recognition of the organization’s distinctive element, the human being. It’s in this holistic context, centralized around the objective need to increment the organizational commitment, that the Guarda Nacional Republicana tries to evaluate the performance of its militaries, through the application of its Merit Assessment Regulations, as a manner of verifying the way these contribute to the defined aims of the institution. Therefore, it is of evident importance the investigation that, concomitantly, analyses how the evaluation system is accepted, interiorized and understood by the militaries of the institution, along with understanding how much that same evaluation system comes as an objective advantage on the promotion of the operational performance, allowing the development of the career of the more capable and guided for the institutional mission. According to this, and considering the unity that is adjudicated to the professional category of Officials, the only elements of the evaluation system that are both evaluated and evaluators, this research, through the use of a set of questions made to a sample of 294 Officials, tries to discover the social representation that they have of the evaluation system that is now applied in the Guarda Nacional Republicana.

Los niños de edad escolar, en el conflicto del fenómeno del divorcio

El presente trabajo se desarrolló con la intención de analizar la influencia del fenómeno del divorcio en el desarrollo de los niños y niñas de edad escolar. Se considera un tema de actualidad e importancia debido al incremento de la tasa de divorcios en el Ecuador durante los últimos cinco años. Se realizó una investigación documental a través de la cual se hizo una sistematización de aspectos teóricos sobre el tema donde se analizaron los postulados de los principales autores, así como fueron presentadas investigaciones con abordajes similares sobre la temática, las cuales constituyen antecedentes de obligada referencia.

Base de dados relacional de controlos de segurança da informação

No desenvolvimento deste Trabalho de Investigação Aplicada, pretende-se responder à questão: Quais os requisitos necessários a implementar numa base de dados relacional de controlos de segurança da informação para Unidades, Estabelecimentos ou Órgãos militares do Exército Português? Deste modo, para se responder a esta questão central, houve necessidade de subdividir esta em quatro questões derivadas, sendo elas: 1. Quais as principais dimensões de segurança da informação ao nível organizacional? 2. Quais as principais categorias de segurança da informação ao nível organizacional? 3. Quais os principais controlos de segurança da informação a implementar numa organização militar? 4. Quais os requisitos funcionais necessários a implementar numa base de dados de controlos de segurança da informação a implementar numa organização militar? Para responder a estas questões de investigação, este trabalho assenta numa investigação aplicada, com o objetivo de desenvolver uma aplicação prática para os conhecimentos adquiridos, materializando-se assim numa base de dados. Ainda, quanto ao objetivo da investigação, este é descritivo, explicativo e exploratório, uma vez que, tem o objetivo de descrever as principais dimensões, categorias e controlos da segurança da informação, assim como o objetivo de explicar quais são os requisitos funcionais necessários a implementar numa base de dados de controlos de segurança da informação. Por último, tem ainda o objetivo de efetuar um estudo exploratório, comprovando a eficácia da base de dados. Esta investigação assenta no método indutivo, partindo de premissas particulares para chegar a conclusões gerais, isto é, a partir de análise de documentos e de inquéritos por entrevista, identificar-se-ão quais são os requisitos funcionais necessários a implementar, generalizando para todas as Unidades, Estabelecimentos ou Órgãos militares do Exército Português. No que corresponde ao método de procedimentos, usar-se-á o método comparativo, com vista a identificar qual é a norma internacional de gestão de segurança de informação mais indicada a registar na base de dados. Por último, como referido anteriormente, no que concerne às técnicas de investigação, será usado o inquérito por entrevista, identificando os requisitos necessários a implementar, e a análise de documentos, identificando as principais dimensões, categoriasou controlos necessários a implementar numa base de dados de controlos de segurança da informação. Posto isto, numa primeira fase da investigação, através da análise de documentos, percecionam-se as principais dimensões, categorias e controlos de segurança da informação necessários a aplicar nas Unidades, Estabelecimentos ou Órgãos militares do Exército Português, por forma a contribuir para o sucesso na gestão da segurança da informação militar. Ainda, através de entrevistas a especialistas da área de segurança da informação e dos Sistemas de Informação nas unidades militares, identificar-se-ão quais os requisitos funcionais necessários a implementar numa base de dados de controlos de segurança da informação a implementar numa organização militar. Por último, numa segunda fase, através do modelo de desenvolvimento de software em cascata revisto, pretende-se desenvolver uma base de dados relacional, em Microsoft Access, de controlos de segurança da Informação a fim de implementar em Unidades, Estabelecimentos ou Órgãos militares do Exército Português. Posteriormente, após o desenvolvimento da base de dados, pretende-se efetuar um estudo exploratório com vista a validar a mesma, de modo a comprovar se esta responde às necessidades para a qual foi desenvolvida.

Síntese enzimática de ésteres de açúcar: surfactantes e polímeros como novos materiais ambientalmente seguros

Sugar esters are substances which possess surfactant, antifungical and bactericidal actions and can be obtained through two renewable sources of raw materials: sugars and vegetable oils. Their excellent biodegradability, allied to lhe fact that they are non toxic, insipid, inodorous, biocompatible, no-ionic, digestible and because they can resist to adverse conditions of temperature, pH and salinity, explain lhe crescent use of these substances in several sections of lhe industry. The objective of this thesis was to synthesize and characterize surfactants and polymers containing sugar branched in their structures, through enzymatic transesterification of vinyl esters and sugars, using alkaline protease from Bacillus subtilis as catalyst, in organic medium (DMF).Three types of sugars were used: L-arabinose, D-glucose and sucrose and two types of vinyl esters: vinyl laurate and vinyl adipate. Aiming to reach high conversions from substrates to products for a possible future large scale industrial production, a serie of variables was optimized, through Design of Experiments (DOE), using Response Surface Methodology (RSM).The investigated variables were: (1) enzyme concentration; (2) molar reason of substrates; (3) water/solvent rale; (4) temperature and (5) time. We obtained six distinct sugar esters: 5-0-lauroyl L-arabinose, 6-0-lauroyl D-glucose, 1'-O-lauroyl sucrose, 5-0-vinyladipoyl L-arabinose, 6-0-vinyladipoyl D-glucose and 1 '-O-vinyladipoyl sucrose, being lhe last three polymerizable. The progress of lhe reaction was monitored by HPLC analysis, through lhe decrease of sugar concentration in comparison to lhe blank. Qualitative analysis by TLC confirmed lhe formation of lhe products. In lhe purification step, two methodologies were adopted: (1) chromatographic column and (2) extraction with hot acetone. The acylation position and lhe chemical structure were determined by 13C-RMN. The polymerization of lhe three vinyl sugar esters was possible, through chemical catalysis, using H2O2 and K2S2O8 as initiators, at 60°C, for 24 hours. IR spectra of lhe monomers and respective polymers were compared revealing lhe disappearance of lhe vinyl group in lhe polymer spectra. The molar weights of lhe polymers were determined by GPC and presented lhe following results: poly (5-0-vinyladipoyl L-arabinose): Mw = 7.2 X 104; PD = 2.48; poly (6-0-vinyladipoyl D-glucose): Mw = 2.7 X 103; PD = 1.75 and poly (1'-O-vinyladipoyl sucrose): Mw = 4.2 X 104; PD = 6.57. The six sugar esters were submitted to superficial tension tests for determination of the critical micelle concentrations (CMC), which varied from 122 to 167 ppm. Finally, a study of applicability of these sugar esters, as lubricants for completion fluids of petroleum wells was' accomplished through comparative analysis of lhe efficiency of these sugar esters, in relation to three commercial lubricants. The products synthesized in this thesis presented equivalent or superior action to lhe tested commercial products