This diploma thesis "The effect of CNG fuel combustion on the technical and economic parameters of the vehicle" deals with the use of alternative fuel of compressed natural gas for road vehicles. The thesis is divided into 4 main parts. In the first part there is a literary review, which deals with the history of the use of gaseous fuels in the world and in the Czech lands, as well as the characteristics and construction part of the car modified for CNG operation. The second part is an experimental measurement of performance parameters of two Škoda Octavia Combi III vehicles with a CNG, diesel and petrol engine at dynamometer testing laboratory, which is also described in this chapter. In the third part the results of experimental measurement are processed and commented and both vehicles are compared from the technical and economical point of view. As is evident from the measurement results, in a vehicle that is already equipped with CNG system from manufacturer combustion CNG does not have a negative effect on the engine's performance parameters and even more constant engine operation can be observed. Vehicles with CNG system are also more economical and ecological than vehicles combusting conventional fuels. The last part of this thesis is devoted to a discussion, where the measured results are compared with the results in an expert article dealing with the same topic.

An updated version of the EUV-TEC proxy, describing the total primary ionisation of the upper atmosphere, is calculated from satellite-borne EUV measurements. Regional number densities of the background model atmosphere consisting of four major constituents are taken from the NRLMSISE-00 climatology. Furthermore, a first estimate of a global thermospheric heating rate is calculated from the absorbed energy. For the calculations the Lambert-Beer law is used to describe the decrease of the radiation along their way through the atmosphere. The EUV-TEC proxy is compared against the global mean total electron content (TEC), obtained from vertical TEC maps derived from GPS data. Strong correlations between these indices are found on different time scales. Results show that the EUV-TEC proxy describes the ionospheric variability better than the conventional solar index F10.7, especially at short time scales of days to weeks.

No description available.

Spacecraft formation flying (SFF) offers robust observations of multi-scale ionospheric space weather. A number of hardware-in-the-loop (HIL) SFF simulation testbeds based on Global-Navigation-Satellite-Systems (GNSS) have been developed to support GNSS-based SFF mission design, however, none of these testbeds has been directly applied to ionospheric space weather studies. The Virginia Tech Formation Flying Testbed (VTFFTB), a GNSS-based HIL simulation testbed, has been developed in this work to simulate closed-loop real-time low Earth orbit (LEO) SFF scenarios. The final VTFFTB infrastructure consists of three GNSS hardware signal simulators, three multi-constellation multi-band GNSS receivers, three navigation and control systems, an STK visualization system, and an ionospheric remote sensing system. A fleet of LEO satellites, each carrying a spaceborne GNSS receiver for navigation and ionospheric measurements, is simulated in scenarios with ionospheric impacts on the GPS and Galileo constellations. Space-based total electron density (TEC) and GNSS scintillation index S4 are measured by the LEO GNSS receivers in simulated scenarios. Four stages of work were accomplished to (i) build the VTFFTB with a global ionospheric modeling capability, and (ii) apply the VTFFTB to incubate future ionospheric measurement techniques. In stage 1, a differential-TEC method was developed to use space-based TEC measurements from a pair of LEO satellites to determine localized electron density (Ne). In stage 2, the GPS-based VTFFTB was extended to a multi-constellation version by adding the Galileo. Compared to using the GPS constellation only, using both GPS and Galileo constellations can improve ionospheric measurement quality (accuracy, precision, and availability) and relative navigation performance. Sensitivity studies found that Ne retrieval characteristics are correlated with LEO formation orbit, the particular GNSS receivers and constellation being used, as well as GNSS carrier-to-noise density C/N0. In stage 3, the VTFFTB for dual-satellite scenarios was further extended into a 3-satellite version, and then implemented to develop a polar orbit scenario with more fuel-efficient natural motion. In stage 4, a global 4-dimensioanl ionospheric model (TIE-CGM) was incorporated into the VTFFTB to significantly improve the modelling fidelity of multi-scale ionospheric space weather. Equatorial and polar space weather structures (e.g. plasma bubbles, tongues-of-ionization) were successfully simulated in 4-dimensional ionospheric scenarios on the enhanced VTFFTB. The dissertation has demonstrated the VTFFTB is a versatile GNSS-based SFF mission incubator to study ionospheric space weather impacts and develop next-generation multi-scale ionospheric observation missions. / Doctor of Philosophy / Spacecraft formation flying (SFF) is a space mission architecture with a group of spacecraft flying together and working as a team. SFF provides new opportunities for robust, flexible and low-cost observations of various phenomena in the ionized layer of Earth's atmosphere (called the ionosphere). Several hardware SFF simulation platforms based on Global Navigation Satellite Systems (GNSS) have been established to develop GNSS-based SFF missions, however, none of these platforms has ever directly used on-board GNSS receivers to study the impact of space weather on ionospheric density structures. The Virginia Tech Formation Flying Testbed (VTFFTB), a hardware simulation infrastructure using multiple GNSS signals, has been built in this work to emulate realistic SFF scenarios in low altitude orbits. The overall VTFFTB facility comprises three GNSS hardware signal emulators, three GNSS signal receivers, three navigation and control components, a software visualization component, and an ionospheric measurement component. Both Global-Positioning-System (GPS) and Galileo (the European version GNSS) are implemented in the VTFFTB. The objectives of this work are to (i) develop the VTFFTB with a high-fidelity ionospheric modeling capability, and (ii) apply the VTFFTB to incubate future ionospheric measurement techniques with GNSS receivers in space. A fleet of two or three spacecraft, each having a GNSS receiver to navigate and sense the ionosphere is emulated in several space environments. The electron concentration of the ionosphere and the GNSS signal fluctuation are measured by the GNSS receivers from space in simulated scenarios. These measurements are advantageous to study the location, size and structure of irregular ionospheric phenomena nearby the trajectory of spacecraft fleet. The culmination of this study is incorporation of an external global ionospheric model with temporal variations into the VTFFTB infrastructure to model a variety of realistic ionospheric structures and space weather impacts. Equatorial and polar space weather phenomenon were successfully simulated on the VTFFTB to verify a newly developed space-borne electron density measurement technique in the 3-dimensional ionosphere. Overall, it was successfully demonstrated that the VTFFTB is a versatile GNSS-based SFF mission incubator to study multiple kinds of ionospheric space weather impacts and develop next-generation space missions for ionospheric measurements.

The Global Navigation Satellite System (GNSS) is significantly advantageous to absolute and relative navigation for spacecraft formation flying. Ionospheric remote sensing, such as Total Electron Content (TEC) measurements or ionospheric irregularity studies are important potential Low Earth Orbit (LEO) applications. A GNSS-based Hardware-in-the-loop (HIL) simulation testbed for LEO spacecraft formation flying has been developed and evaluated. The testbed infrastructure is composed of GNSS simulators, multi-constellation GNSS receiver(s), the Navigation & Control system and the Systems Tool Kit (STK) visualization system. A reference scenario of two LEO spacecraft is simulated with the initial in-track separation of 1000-m and targeted leader-follower configuration of 100-m along-track offset. Therefore, the feasibility and performance of the testbed have been demonstrated by benchmarking the simulation results with past work. For ionospheric remote sensing, multi-constellation multi-frequency GNSS receivers are used to develop the GNSS TEC measurement and model evaluation system. GPS, GLONASS, Galileo and Beidou constellations are considered in this work. Multi-constellation GNSS TEC measurements and the GNSS-based HIL simulation testbed were integrated and applied to design a LEO satellite formation flying mission for ionospheric remote sensing. A scenario of observing sporadic E is illustrated and adopted to demonstrate how to apply GNSS-based spacecraft formation flying to study the ionospheric irregularities using the HIL simulation testbed. The entire infrastructure of GNSS-based spacecraft formation flying simulation and ionospheric remote sensing developed at Virginia Tech is capable of supporting future ionospheric remote sensing mission design and validation. / Master of Science

La maîtrise de l’additivation est l’un des enjeux majeurs de la formulation des lubrifiants, notamment pour l’industrie automobile. La formulation d’une huile est toutefois très complexe en raison du nombre important d’additifs et des nombreuses interactions possibles entre additifs, notamment entre les additifs de surface. Les phosphites organiques et les polysulfures organiques ont déjà montré leur efficacité en tant qu’additifs de surface. Toutefois malgré leur usage répandu dans les formulations des lubrifiants automobiles, peu d’études traitent des interactions pouvant avoir lieu entre ces deux types de composés. Ce travail de thèse a pour objectif la compréhension des mécanismes d’interaction (antagonisme/synergie) pouvant exister entre les phosphites organiques et les polysulfures organiques. Pour cela, une approche originale sur la lubrification par la phase gazeuse s’est avérée très pertinente. Le couplage du Tribomètre à Environnement Contrôlé (TEC) avec les systèmes d’analyses de surface XPS/Auger a permis d’analyser les tribofilms générés in situ et d’éviter ainsi toute contamination et/ou oxydation du tribofilm avant analyse. Les molécules choisies sont les additifs de lubrification industriels (polysulfures tertaires) à faibles poids moléculaires ou alors des molécules à faible poids moléculaires ayant les mêmes fonctions chimiques que les additifs usuels : trimethyl phosphite (TMPi), dimethyl phosphite (DMPi). L’étude des réactions des tribochimiques des molécules phosphorés a permis de mettre en évidence le rôle ambivalent du DMPi qui se comporte à la fois comme un phosphite pour former un phosphure de fer et comme un phosphate. Le mécanisme formation du phosphure de fer a peu être étayé par la réalisation de calculs ab initio sur l’adsorption dissociative du TMPi sur une surface de fer. Les TPS étudiés génèrent quant à eux des tribofilms à base disulfure de fer. Les mélanges binaires réalisés en phase gazeuse ont permis de mettre en évidence l’importance des rapports de concentrations des vapeurs introduites et du mode d’introduction des molécules dans le tribomètre. Les résultats obtenus en tribologie en phase gazeuse ont été corroborés par des essais complémentaires en phase liquide. / Mastering the addivation is one of the biggest issues for the lubricants formulation, especially in the automobile industry. However automotive lubricants are very complex systems due to the numerous additives mixed with base oils. Many interactions can occur between additives, especially between surface additives. Organic phosphites and organic polysulphides have already demonstrated their effectiveness as surface additives. However, despite their widespread use in the formulations of automotive lubricants, few studies deal with the interactions taking place between these two types of compounds. The aim of this study is to understand the interactions, antagonistic or synergetic effect between these kinds of additives using Gas Phase Lubrication (GPL) approach. A Environmental Controlled Tribometer (TEC) was used as a tool to simulate the interaction between organophosphate additives and polysulfurous additives. In situ surface analysis was performed in the tribofilm formed during friction using of X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy(AES) in order to avoid any oxidation or air contamination. The molecules selected for the study can be same as the additive like the TPS molecules which are widely used as lubricant additives. Howeverto simulate the phosphite chemical function of phosphite additives, we need to select smaller molecule having the same chemical function. These molecules are dimethyl phosphite (DMPi), trimethylphosphate (TMPi) for simulating the phosphite chemical function and organic polysulphides (TPS44and TPS32). The study of the tribochemical reactions of organic phopshites allowed to clearly characterise the ambivalence of DMPi, which can react like a phosphite and induce iron phosphide formation or react like a phosphate. Ab initio numerical simulation on TMPi dissociative adsorption was carried out to identify the reactions pathways leading to iron phosphide formation. The tribochemical reaction of TPS44 on metallic iron surface leads to the formation of iron disulphidebased tribofilm. The binary vapours mixtures studied by GPL allowed to clearly identify the importance of the vapour concentration ratio between phosphite and polysulphide. Liquid phase experiments were also carried out to confirm the trend observed in GPL approach.

Made available in DSpace on 2016-07-27T13:45:08Z (GMT). No. of bitstreams: 1 RENATA LUIZA DA COSTA.pdf: 2917273 bytes, checksum: 4dd40424e715c57ca47117456e37f7f9 (MD5) Previous issue date: 2015-08-24 / This research aimed at identifying and examining ways of teacher mediation in technical courses of e-Tec Network, which is part of the federal Technical Professional Educational system, and its effectiveness regarding the formation objectives mandated by the educational legislation as well as in their curriculum and pedagogic standards in the sense of reaching an education based on scientific, technological, socio-cultural and historical foundations. The analysis carried out on Technical Professional Education in Brazil identify not only the dualism of professional formation once it separates the technical from human formation, but also the intertwining of market interests enhanced by the induction of international organizations, and the technicist tendency of reducing the processes of didactic mediation to merely instrumental procedures. The critical reflection upon these problems (FRIGOTTO, 2001, 2010; FRIGOTTO e CIAVATTA, 2003; KUENZER, 2006, 2009, 2010; EVANGELISTA, 2013; SHIROMA, 2013) raise questions about the efficacy of teachers mediation processes which take place in pedagogic practices of e-Tec Network, its correspondence with the professional profile proposed by the legislation and pedagogic projects, and in the ways of articulating technical and human formation. Thus, this study centres on pedagogic-didactic questions and their direct relation with the political and directive issues for Technical Professional Education, having as theoretical framework the fundamentals of the relation between human emancipation processes and the forms of teaching organization, within the Cultural-Historical Theory (VYGOTSKY, 1931, 2007; DAVYDOV, 1988, 1999; LIBÂNEO, 2004, 2012a, 2012b, 2014; BERNARDES, 2012) as well as the fundamentals of the Educative Intervention Theory (LENOIR, 2011, 2014a). As references about distance education, we based on Toschi (2004, 2011, 2012), Alonso (2011, 2012) and Preti (2000, 2002, 2003, 2005), in order to search for theoretical frameworks that defend the qualitative accuracy of distance courses beyond the democratization of access.The empirical research was conducted in three federal technical education schools, which deal with e-Tec Network, being two federal institutes (IF) and one Federal Center of Technological Education (CEFET). In these schools, we attended online lessons and collected tasks, assessments and lesson plans from seven different subjects. We also conducted interviews with tutors, teachers, coordinators and students from four courses, envolving multiple aspects of the online teacher mediation processes. The data analysis results can point out that the teacher mediation taken online is held mostly in an instrumental order, once it reproduces similar types of traditional teaching methods. The forms of teaching organization and tasks dont include activities that mobilize cognitive operations toward reflection and analyses, nor forms of pedagogic interaction between teacher and students, consolidating practices that bring few contributions to the integral human formation of the students in its personal, social and professional dimension. As a result, the procedures for assessing learning come to verify memorization, repetition, and the performance in technical abilities. Therefore, we conclude that online professional formation developed in the analyzed courses is incoherent with the one stated in official documents and in the pedagogic projects of the aforementioned institutions. On the contrary, it strengthen the existing structural duality and points out to the occurrence of very limited and modest pedagogic-didactic practices which configures itself as a technical course of questionable quality and far from the conditions of integral human formation of students. / A presente pesquisa se propôs identificar e analisar os processos de mediação docente nos cursos técnicos de nível médio online, especificamente os cursos integrantes da Rede e-Tec da esfera federal, buscando verificar os propósitos, as ações educativas, os fatores e as condições essenciais correspondentes a essas ações e objetivos, especialmente, o grau de atenção dado ao processo de ensino-aprendizagem, no sentido de promover uma formação baseada em fundamentos científico-tecnológicos, sócio-históricos e culturais. Análises sobre a Educação Profissional Técnica no Brasil identificam um dualismo nessa formação separando a formação técnica da formação humana, a vinculação aos interesses do mercado acentuada pela indução dos organismos internacionais e a tendência tecnicista de reduzir os processos de mediação didática a procedimentos meramente instrumentais. A reflexão crítica em torno desses problemas (FRIGOTTO, 2001, 2010; FRIGOTTO e CIAVATTA, 2003; KUENZER, 2006, 2009, 2010; EVANGELISTA, 2013; SHIROMA, 2013) leva a indagações sobre a efetividade dos processos de mediação docente que ocorrem nas práticas pedagógicas da Rede e-Tec e sua correspondência com o perfil de profissional preconizado na legislação e nos projetos pedagógicos em relação à articulação entre as formações técnica e humana. Desse modo, este estudo centra-se em questões pedagógico-didáticas em sua relação direta com as políticas e diretrizes para a Educação Profissional Técnica, tendo como referência teórica os fundamentos da relação entre processos de emancipação humana e as formas de organização do ensino na perspectiva da Teoria Histórico-Cultural (VYGOTSKY, 1931, 2007; DAVYDOV, 1988, 1999; LIBÂNEO, 2004, 2012a, 2012b, 2014; BERNARDES, 2012) e aportes da Teoria da Intervenção Educativa (LENOIR, 2011, 2014a). Como referência de educação a distância, nos apoiamos, principalmente, nas pesquisas de Toschi (2004, 2011, 2012), Alonso (2011, 2012) e Preti (2000, 2002, 2003, 2005), tendo em vista a busca por referenciais teóricos que defendem o rigor qualitativo dos cursos a distância para além da democratização do acesso. A pesquisa de campo foi realizada em três escolas de educação técnica da rede federal que implantaram a Rede e-Tec. Nessas escolas, foram observadas aulas no modo online e coletadas tarefas, avaliações e planos de aula de sete diferentes disciplinas. Foram realizadas, também, entrevistas com tutores, professores, coordenadores e alunos de quatro cursos, envolvendo múltiplos aspectos dos processos de mediação docente online. Os resultados da análise dos dados indicam que a mediação docente online é, na maior parte dos casos, de tipo instrumental, reproduzindo modalidades de ensino análogas aos procedimentos de ensino tradicionais e atendendo às demandas neoliberais. As formas de organização do ensino e as tarefas não incluem atividades de mobilização de operações cognitivas voltadas à reflexão e análise, nem formas de interação pedagógica entre alunos e professor, consolidando práticas que pouco contribuem para a formação integral dos alunos em suas dimensões pessoal, social e profissional articuladas. Com isso, os procedimentos de acompanhamento da aprendizagem se reduzem à verificação da memorização, repetição e do desempenho repetitivo de habilidades técnicas. Portanto, a formação profissional a distância desenvolvida nos cursos analisados é contraditória à preconizada nos documentos oficiais e nos projetos pedagógicos das instituições analisadas. Ao contrário, acentua a dualidade estrutural já existente e aponta para a ocorrência de práticas pedagógico-didáticas bastante limitadas e modestas indicando propiciar um ensino técnico qualitativamente questionável e distante de condições de formação integral dos alunos.

Submitted by admin tede (tede@pucgoias.edu.br) on 2018-11-08T19:09:17Z No. of bitstreams: 1 GUENTHER CARLOS FEITOSA DE ALMEIDA.pdf: 3010694 bytes, checksum: f25311137c9833299ddb3801f3287fb0 (MD5) / Made available in DSpace on 2018-11-08T19:09:17Z (GMT). No. of bitstreams: 1 GUENTHER CARLOS FEITOSA DE ALMEIDA.pdf: 3010694 bytes, checksum: f25311137c9833299ddb3801f3287fb0 (MD5) Previous issue date: 2018-08-17 / The Rede e-Tec Brasil, regulated by Decree n. 7,589, October 26, 2011, offers professional education on distance mode. This program was formulated in the disputes around the Brazilian professional formation of the 21st century. Currently, the Rede e-Tec Brasil is part of the National Program of Access to Technical Education and Employment (PRONATEC), which offers professional education in public institutions and in National Learning Services (Sistema S). The main objective of this research was analyze which conceptions of education and work are in dispute in the public policy of professional and technological distance education (Rede e-Tec Brasil) in a professional education institution. The specific objectives were: a) to understand the delineations, the mediations and the contradictions present in the formation of the contemporary worker; b) analyze the conceptions of work and education in the official documents that regulate the policy of e-Tec Brasil Network nationally; c) to elucidate, in the documents that organize the courses offered by e-Tec Brazil Network in the institution researched, in what way the fundamental relationship between work and education is presented; d) unveil how the managers responsible for e-Tec Brazil Network in the institution and the students of the courses taught characterize the relationship between work and education. Thus, the research problem was formulated: Which are the conceptions of work and education are present and are the protagonists of disputes in the public policy for the training of distance workers (Rede e-Tec Brasil) of a professional education institution? The guiding axes of the theoretical reference were: a) capital crisis, production organization and distance worker training with support in Antunes (2009a, 2011b, 2013); Alves, G. (2011); Harvey (2011, 2013); Silva Júnior and Martins (2013), Duarte (2008); b) structural duality in Brazilian professional education in Cunha's writings (2000a, 2000b, 2005); Manfredi (2002); Caires and Oliveira (2016); Frigotto (2001); Ciavatta and Ramos (2011); Silva, M. R. (2010); c) polytechnic training of the worker with contribution of Saviani (2007a, 2008); Frigotto (2001, 2010a, 2011); Moura and Lima Filho (2017); Lima Filho (2015); Kuenzer (1991); Rummert (1998); Ciavatta and Ramos (2011); Ramos (2002). Thus, an investigation anchored in Marx's historical-dialectical materialism was proposed, understanding that social reality is the consequence of human activity, and that professional education policies are the result of the performance of historical subjects in a Brazilian capitalist society. The approach of the research is qualitative, having as methodological procedures the documentary analysis, interviews with managers and discussion groups with students. From the empirical data analysis, four categories emerged: a) The configuration of Rede e-Tec Brazil; b) the management of the market in the training of workers; c) the emptied content of the workers training; d) ruptures and continuities in the formation of the worker. It is concluded, therefore, that the organization of this EaD policy distanced itself from the polytechnical training, since the Rede e-Tec Brasil reproduced the fragmentation of the educational work and the knowledge of the professional education, with the presence of a market-oriented education , lightened and aimed at adapting subjects to flexibilization, informality, entrepreneurship and efficiency; the reduction of education and work to the practical experimentation of the making of a profession; the reaffirmation of structural duality in education materialized by the fragmentation between knowledge of work, science and culture. It is also concluded that, in the institutional context, some specific actions of articulation between work, science and culture were verified. / A Rede e-Tec Brasil, regulamentada pelo Decreto n.º 7.589, 26 de outubro de 2011, oferta educação profissional a distância. Esse programa foi formulado nas disputas em torno da formação profissional brasileira do século XXI. Atualmente, a Rede e-Tec Brasil está vinculada ao Programa Nacional de Acesso ao Ensino Técnico e Emprego (PRONATEC), que oferece educação profissional em instituições públicas e em Serviços Nacionais de Aprendizagem (Sistema S). Quanto ao objetivo geral, esta investigação analisou quais concepções de educação e trabalho se encontram em disputa na política pública de educação profissional e tecnológica a distância (Rede e-Tec Brasil) em uma instituição de educação profissional. Já os objetivos específicos foram: a) compreender os delineamentos, as mediações e as contradições presentes na formação do trabalhador contemporâneo; b) analisar as concepções de trabalho e educação nos documentos oficiais que regulamentam nacionalmente a política da Rede e-Tec Brasil; c) elucidar, nos documentos que organizam os cursos ofertados pela Rede e-Tec Brasil na instituição pesquisada, de que maneira se apresenta a relação fundamental entre trabalho e educação; d) desvendar como os gestores responsáveis pela Rede e-Tec Brasil na instituição e os estudantes dos cursos ministrados caracterizam a relação entre trabalho e educação. Desse modo, o problema de pesquisa foi assim formulado: Quais concepções de trabalho e educação estão presentes e protagonizam disputas na política pública de formação dos trabalhadores a distância (Rede e-Tec Brasil) de uma instituição de educação profissional? Como eixos orientadores do referencial teórico, estes foram: a) crise do capital, organização da produção e formação do trabalhador a distância com apoio em Antunes (2009a, 2011b, 2013); Alves, G. (2011); Harvey (2011, 2013); Silva Júnior e Martins (2013), Duarte (2008); b) dualidade estrutural na educação profissional brasileira nos escritos de Cunha (2000a, 2000b, 2005); Manfredi (2002); Caires e Oliveira (2016); Frigotto (2001); Ciavatta e Ramos (2011); Silva, M. R. (2010); c) formação politécnica do trabalhador com aporte de Saviani (2007a, 2008); Frigotto (2001, 2010a, 2011); Moura e Lima Filho (2017); Lima Filho (2015); Kuenzer (1991); Rummert (1998); Ciavatta e Ramos (2011); Ramos (2002). Propôs-se assim uma investigação ancorada no materialismo histórico-dialético de Marx, compreendendo que a realidade social é fruto da atuação dos seres humanos, sendo as políticas de educação profissional resultado da atuação de sujeitos históricos em uma sociedade capitalista, a brasileira. A abordagem da pesquisa é qualitativa, tendo como procedimentos metodológicos a análise documental, entrevistas com gestores e grupos de discussão com estudantes. Da análise dos dados empíricos, emergiram quatro categorias: a) a Rede e-Tec Brasil em sua configuração; b) a regência do mercado sobre a formação dos trabalhadores; c) o esvaziamento do conteúdo da formação do trabalhador; d) rupturas e continuidades na formação do trabalhador. Conclui-se, portanto, que a organização desta política de EaD se distanciou da formação politécnica, visto que a Rede e-Tec Brasil reproduziu a fragmentação do trabalho educativo e do conhecimento da educação profissional, havendo a presença de uma educação voltada para o mercado, aligeirada e que visa adequar os sujeitos à flexibilização, à informalidade, ao empreendedorismo e à eficiência; a redução da educação e do trabalho à experimentação prática do fazer de uma profissão; a reafirmação da dualidade estrutural na educação materializada pela fragmentação entre conhecimentos do trabalho, das ciências e da cultura. Conclui-se ainda que, no âmbito institucional, foram constatadas algumas ações específicas de articulação entre trabalho, ciência e cultura.

This PhD thesis presents investigations of perovskite-related compounds in systems of interest for applications in components in solid oxide fuel cells. The compound compositions derive from substitutions in the parent compounds LaCoO3, LaCrO3 and SrFeO3. Novel phases La2Co1+z(MgxTi1-x)1-zO6 were synthesized and investigated with regard to structure, thermal expansion, electronic and magnetic properties. The study focused on the composition lines La2Co(MgxTi1-x)O6 (z=0), where the oxidation state of Co nominally changes from +2 (x=0.0) to +3 (x=0.5), and La2Co1+z(Mg0.5Ti0.5)1-zO6, with a varying fraction of Co3+ ions. XANES data show that the Co ions in the system have discrete oxidation states of +2 and +3. The TEC increases with increasing x due to an increasing contribution from spin state transitions of the Co3+ ions. Novel compounds La2Cr(M2/3Nb1/3)O6 with M=Mg, Ni, Cu were synthesized and characterized with respect to structure and magnetic properties. XRPD and NPD data indicate Pbnm symmetry; however, SAED patterns and HREM images indicate a P21/n symmetry for M=Mg, and Cu. The magnetic measurements results were rationalized using the Goodenough-Kanamori rules. Oxygen-deficient phases with x≥0.63 in SrxY1-xFeO3-δ and Sr0.75Y0.25Fe1-yMyO3-δ (M=Cr, Mn, Ni and y=0.2, 0.33, 0.5), were synthesized and characterized with respect to structure, oxygen content, thermogravimetry, TEC, conductivity and magnetic properties. Powder patterns of phases agree with cubic  perovskite structures. NPD data for x=0.75 reveal anisotropic displacement for the O atom, related to local effects from Fe3+/Fe4+ ions. SAED patterns for x=0.75 reveal the presence of an incommensurate modulation. The compounds start to lose oxygen in air at ~ 400°C. The TEC up to ~400°C for x=0.75 is ~10.5 ppm/K and increase to ~17.5 ppm/K at higher temperatures. The conductivity for x=0.91 is 164 S/cm at 400°C. Partial substitution of Fe by Cr, Mn or Ni does not increase the conductivity or decrease TEC.

The development of materials for advanced applications requires innovative macromolecules with well-defined structures and the inherent ability to be tailored in a straightforward manner. Dendrimers, being a subgroup of the dendritic polymer family, possess properties which fulfill such demands. They have a highly branched architecture with a high number of functional groups and are one of the most well-defined types of macromolecules ever synthesized. However, despite their well-defined nature and high functional density, traditional dendrimers commonly lack diverse chemical functionalities. Therefore, this thesis focuses on the synthesis of more complex dendritic materials to extend their tailoring capacity by introduction of dualfunctionalities for multipurpose actions. It covers the synthesis of dualfunctional dendrimers, dendritic modification of linear poly(ethylene glycol) polymers and cellulose surfaces, and the synthesis of linear dendritic hybrids. The building blocks enabling this synthesis, AB2C monomers, were also developed during this work. The orthogonal nature between click groups (azide, alkyne and alkene) and hydroxyl groups have efficiently been utilized for postfunctionalization by robust click chemistry and traditional esterification reactions. Furthermore, linear dendritic hybrids were synthesized, merging the properties of linear and dendritic macromolecules. The dendritic frameworks were tailored towards the production of bone fracture adhesives, novel biofunctional dendritic hydrogels, biosensors and micellar drug delivery vehicles. / Utveckling av material för avancerade applikationer kräver innovativa makromolekyler med väldefinierade strukturer och som kan skräddarsys på ett enkelt sätt. Dendrimerer är en undergrupp av dendritiska polymerer vars egenskaper uppfyller dessa krav. De har en mycket förgrenad arkitektur med många funktionella grupper och är en av de mest väldefinierade befintliga syntetiska makromolekylerna. Trots dess väldefinierade karaktär och höga funktionalitet saknar ofta traditionella dendrimerer multipla kemiska funktionaliteter. Denna avhandling fokuserar därför på syntesen av mer komplexa dendritiska material för att förbättra deras kapacitet att skräddarsys, detta görs genom att introducera fler funktionaliteter som kan utnyttjas för multipla ändamål . Avhandlingen redogör för syntesen av difunktionella dendrimerer, dendritiska modifikationer av polyetylenglykol och cellulosaytor samt syntes av traditionella dendritiska hybrider. Byggstenarna som möjliggör syntesen, AB2C monomerer, framställdes också under detta arbete. Den ortogonala karaktären mellan klick grupper (azid, alkyn och alkene) och hydroxylgrupper har utnyttjats effektivt för funktionaliseringar genom användande av robust ”Click”-kemi och traditionella esterifikationsreaktioner. Vidare tillverkades de linjära dendritiska hybrider för att kombinera egenskaperna hos både linjära och traditionella dendritiska polymerer i en och samma makromolekyl. Samtliga dendritiska strukturer skräddarsyddes för applikationer så som benlimmer, biofunktionella dendritiska hydrogeler, biosensorer och läkemedels-bärande miceller. / <p>QC 20130830</p>