No description available.

No description available.

Magister Pharmaceuticae - MPharm / The objective was to prepare new solid phases, i.e. co-crystal forms, of two sulfa antibiotic drugs (sulfamethoxazole and sulfasalazine) with trimethoprim and fourteen potential co-formers with GRAS status. Trimethoprim was chosen for its synergistic effects with both sulfa drugs and the other co-formers were selected in an attempt to improve the physicochemical properties of the antibiotics. A variety of co-crystallization techniques, including solvent assisted grinding, slow evaporation, slurry method and solidification of the melt were used to obtain these results. From these methods, three new solid phases were successfully isolated for the sulfamethoxazole antibiotic, viz. sulfamethoxazole-benzoic anhydride (SMZ-BAN) co-crystal by the slurry method, amorphous sulfamethoxazole-trimethoprim (SMZ-TMP) form by solidification of the melt and amorphous sulfamethoxazole-oxalic acid (SMZ-OA) by slow evaporation. For the sulfasalazine antibiotic, co-crystallization experimentation produced, sulfasalazine-trimethoprim salt (SSZ-TMPs) by slow evaporation, sulfasalazine-trimethoprim co-crystal (SSZ-TMP) by solvent assisted grinding and sulfasalazine-nicotinamide co-crystal (SSZ-NC) by solidification of the melt. Of these six compounds subjected to single crystal X-ray analysis, only one of their structures was elucidated i.e. the salt, SSZ-TMPs. Different techniques that were used to assess the thermal behaviour of the products included hot stage microscopy, differential scanning calorimetry and thermogravimetric analysis. FTIR provided information on the purity of the compounds and the suggested host-guest interaction sites. X-ray powder diffraction supported the determination of the new phase comparative to the parent compounds. Finally dissolution testing was carried out for successful candidates with encouraging recommendations for future work.

Long span flat slab systems with internal spherical void formers have been used in Europe for a decade now. Cobiax® is the brand name of a successful system, recently introduced in South Africa. It is a bi-axial reinforced concrete flat slab system, with a grid of internal spherical void formers. The main advantage is the possibility of long spans due to the significant reduction in own weight, as well as the fast construction sequence with the use of flat slab formwork systems. Design requirements of SANS 10100:2000 are affected. Vertical shear capacity is a concern due to loss of aggregate interlock. Research in Germany proved a factor of 0.55 to be a conservative shear resistance reduction factor for Cobiax slabs. Theoretical and preliminary laboratory South African research suggests that a greater factor of 0.85 might be used when considering the shear capacity of the steel cages. These cages’ vertical legs also cross the cold joint caused by the two concrete pours required for Cobiax slabs, and proved to provide sufficient horisontal shear resistance if the correct cage diameters are used. Laboratory tests in Germany supported by theoretical calculations further showed reduced deflections for Cobiax slabs. Although stiffness and own weight are reduced due to the voids, Cobiax slabs had smaller absolute deflections than solid slabs with the same thickness. Cobiax research factors are safe to apply to SANS 10100-01:2000. The economy of Cobiax slabs was tested against that of coffer and post-tensioned slabs. Different span lengths and loads were considered. Based on 2007 material costs in South Africa, Cobiax slabs subject to the same loads and span lengths will be slightly more expensive than that of coffer slabs and post-tensioned slabs when considering only direct slab construction costs. Cobiax will be most appropriate where a flat soffit is required for high multi-storey buildings, requiring large spans with a light load application. Copyright / Dissertation (MEng)--University of Pretoria, 2010. / Civil Engineering / unrestricted

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Among the three common gas hydrate structures, structure-H (sH) hydrate has been regarded as forming only in the laboratory since it was first reported in 1987. However, natural gas hydrate samples obtained from the Cascadia margin showed that sH hydrate can form naturally. Not only was the sH hydrate found in natural samples, but it was also discovered that n-alkanes such as n-pentane and n-hexane, considered to have too large molecular size to be sH hydrate formers, can act as co-guests of sH hydrates in mixtures with other sH hydrate formers. In this study, thermodynamic measurements and spectroscopic analysis of powder X-ray diffraction and 13C solid-state NMR methods, were performed for synthetic hydrate samples in order to identify the accommodation of n-alkanes with five or more carbon atoms. In addition, some new hydrate guests were found to form sH hydrates. From the present results, it is clear that, so far, our understanding of gas hydrates and guest enclathration needs to be revised and expanded in order to explain new findings.

The efficient production of hydrogen hydrates is a major goal in the attempt to exploit those materials as an alternative means for storing hydrogen. Up to now, a few processes have been reported in the literature which yield less than 1 wt% of hydrogen stored into clathrate hydrate or semi-clathrate forms. One main obstacle to the entrapment of sensible amounts of hydrogen (i.e., up to 4 wt% ) into a clathrate matrix appears to be of a kinetic origin, in that the mass transfer of hydrogen gas into clathrate structures is drastically limited by the (relatively) macroscopic scale of the gas-liquid or gas-ice interfaces involved. In this communication, we present a novel process for an enhanced production of binary hydrates of hydrogen and other hydrate-forming gases, which is characterized by the use of nanotechnology for reducing the size of hydrate particles down to a few nanometers. This drastic reduction of particle size, down to three orders of magnitude smaller than that obtainable by macroscopic methods, allows to reduce the kinetic hindrance to hydrate formation. This process has a huge potential for increasing the amount of hydrogen stored, as it has provided ca. 1 wt% of hydrogen, with THF as a co-former. The present process also allows to use several non-water soluble coformers; first reports of hydrogen/cyclopentane and hydrogen/tetrahydrothiophene hydrates are presented.

The primary intention with this Doctoral thesis is to fillin the knowledge gaps and raise the level of understandingregarding the different metal dusting mechanisms in general andexplain the process in detail for high alloyed materials.Considerable effort is put into identifying the driving forcesand elucidating the diffusional processes in metal dusting. The results are based on a series of long-term laboratory exposures of stainless steels and high-performance commercial alumina-forming Fe- and Ni-base alloys in synthesis gasmixtures, plus a separate shorter study on ultra pure iron. ANi-base alloy was also investigated after a two years field exposure in a methanol plant. Post exposure metallographic examinations and analysis aswell as thermodynamic calculations were made in order toidentify and describe the operating metal dusting mechanisms.Two main mechanisms were previously used to explain metaldusting, one on the basis of decomposition of metastable carbides (Type I) the other on graphite formation (TypeII). A new metal dusting mechanism has been identified in this Thesis which appears on high alloyed steels and Ni-base alloys,an active corrosion induced by carbon and oxygen, denoted TypeIII. Both the mechanisms and the type of corrosion products were consistent with the thermodynamic conditions of the material under the influence of a carbon and oxygen gradient.It was shown that this mechanism not only accelerates the metaldusting process, in fact, it determines the overall metaldusting kinetics on stainless steels and Ni-base alloys. Another feature, which may occur at temperatures where metalbulk and even static grain boundary diffusion is too slow forexplaining the metal dusting corrosion process, was identifiedon a Ni-base alloy. It involves a fast growing cellular structure with discontinuous precipitated carbides whichprovides fast metal dusting kinetics by the Type IIImechanism. A Type IV metal dusting mechanism, continued fragmentationby graphitization until nano-sized particles are formed andcatalyse carbon nanotube formation is also described. Thesteady state process and the driving force for metal dusting onpure iron was identified and described. With these additional processes it is now possible to extendour understanding of the metal dusting processes to a widerange of engineering alloys. / QC 20100825

<div> Design rules and application spaces for closed-shell conjugated polymers have been well established in the field of organic electronics, and this has allowed for significant breakthroughs to occur in myriad device platforms [e.g., organic field-effect transistors (OFETs) and organic light-emitting devices (OLEDs)]. Conversely, organic electronic materials that are based on the emerging design motif that includes open-shell stable radicals have not been evaluated in such detail, despite the promise these materials show for charge transfer, light-emission, and spin manipulation platforms. Moreover, recent results have demonstrated that the materials performance of hybrid systems will allow for future applications to harness both of these platform design archetypes to generate composites that combine the performance of current state-of-the-art conjugated polymer systems with the novel functions provided by open-shell species. Thus, establishing the underlying physical phenomena associated with the interactions between both classes of materials is imperative for the effective utilization of these soft materials.</div><div><br></div><div> In the first part of this work, Förster resonance energy transfer (FRET) is demonstrated to be the dominant mechanism by which energy transfer occurs from a common conjugated polymer to various radical species using a combination of experimental and computational approaches. Specifically, this is determined by monitoring the fluorescence quenching of poly(3hexylthiophene) (P3HT) in the presence of three radical species: (1) the galvinoxyl; (2) the 2phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl (PTIO); and (3) the 4-hydroxy-2,2,6,6tetramethylpiperidine-1-oxyl (TEMPO) radicals. Both in solution and in the solid-state, the galvinoxyl and PTIO radicals show quenching on par with that of a common fullerene electronaccepting derivative. Conversely, the TEMPO radical shows minimal quenching at similar concentrations. Using both ultrafast transient absorption spectroscopy and computational studies, FRET is shown to occur at a significantly faster rate than other competing processes. These findings suggest that long-range energy transfer can be accomplished in applications when radicals that can act as FRET acceptors are utilized, forming a new design paradigm for future applications involving both closed- and open-shell soft materials.</div><div><br></div><div> Following this, addition of the galvinoxyl radical to P3HT is shown to alter the thin film transistor response from semiconducting to conducting. This is accompanied by a modest enhancement in electrical conductivity. This interaction is not seen with either the TEMPO or PTIO radicals. While an increase in charge carrier concentration is observed, the interaction is not otherwise consistent with a simple charge-transfer doping mechanism, due to the mismatched reduction and oxidation potentials of the two species. Additionally, no freeze-out of charge carriers is observed at reduced temperatures. It is also not due to parallel conduction through the radical fraction of the bulk composite, as the radical species is non-conductive. Hole mobility is enhanced at lower concentrations of the radical, but it decreases at higher concentrations due to the reduced fraction of conductive material in the polymer bulk. Despite the increase in mobility at lower concentrations, the activation energy for charge transport is increased by the presence of the radical. This suggests that the radical is not improving the charge transport through filling of deep trap states or by reducing the activation energy for the charge transport reaction; however, the galvinoxyl radical is likely filling shallow trap states within the P3HT for the composite thin film.</div><div><br></div><div> Finally, a novel analysis technique for polymer relaxation is investigated through dielectric spectroscopy of model polyalcohols. An understanding of relaxation phenomena and the physics of amorphous solids in general remains one of the grand open challenges in the field of condensed matter physics. This problem is particularly relevant to organic electronics as many organic electronic materials are found in the amorphous state, and their physical relaxation can lead to undesirable effects such as hysteresis and instability. Current procedures describe relaxation phenomena in terms of empirical functions, but the physical insights provided by this representation are limited. The new approach instead represents the dielectric response as a spectrum of Debye processes. Rather than varying the spectral strength at fixed time points as traditional spectral analysis implicitly does, this approach instead varies the characteristic time of each spectral element while the strength remains fixed. This allows the temperature dependence on relaxation time of each spectral element to be determined, and the <i>α</i>- and <i>β</i>-relaxation are interpreted in light of this analysis. </div><div> </div>

Submitted by RAQUEL POZZENATO SILAZAKI null (rpsilazaki@hotmail.com) on 2017-03-28T12:55:47Z No. of bitstreams: 1 Dissertação Final de Mestrado Raquel Pozzenato Silazaki.pdf: 3326993 bytes, checksum: 7ca4f075b1b0870ddc917c44afeade90 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-03-29T20:33:40Z (GMT) No. of bitstreams: 1 silazaki_rp_me_prud.pdf: 3326993 bytes, checksum: 7ca4f075b1b0870ddc917c44afeade90 (MD5) / Made available in DSpace on 2017-03-29T20:33:40Z (GMT). No. of bitstreams: 1 silazaki_rp_me_prud.pdf: 3326993 bytes, checksum: 7ca4f075b1b0870ddc917c44afeade90 (MD5) Previous issue date: 2017-02-10 / Este estudo desenvolveu-se no interior da linha de pesquisa “Formação dos Profissionais da Educação, Políticas Educativas e Escola Pública” do Programa de Pós-Graduação em Educação da Faculdade de Ciências e Tecnologia, UNESP/Presidente Prudente. Investigou as ações voltadas à formação continuada e à atuação dos Coordenadores Pedagógicos do Ensino Fundamental I, do Sistema Municipal de Ensino de Araçatuba-SP, especificamente das Escolas de Tempo Integral e de Atividades Complementares. A análise focaliza as concepções acerca da formação desses profissionais, compreendidos por nós como formadores de professores da Educação Básica (RINALDI, 2009) e sobre os desafios pertinentes à sua prática neste complexo processo de implementação de um ‘novo modelo de escola’ ainda em construção no município. Esta pesquisa derivou da proposta “A Formação de Professores e a Escola de Tempo Integral: políticas, práticas e desafios” (FAPESP 2014/14750-4). Adotou a abordagem qualitativa de pesquisa em educação a partir de uma matriz teórica interpretativa (PACHECO, 1995), por meio da qual buscou-se compreender o processo de aprendizagem profissional dos Coordenadores Pedagógicos em exercício nessas escolas, a partir de sua participação em um curso de formação continuada, que considerou os seus conhecimentos, atuação e suas demandas cotidianas. Desenvolveu-se via pesquisa bibliográfica, documental e pela coleta de dados, por meio do trabalho empírico, pautada na perspectiva construtivo-colaborativa (COLE; KNOWLES, 1993) de pesquisa-intervenção. Participaram 7 Coordenadores, de 5 escolas. A coleta de dados ocorreu a partir do desenvolvimento do curso, na modalidade de aperfeiçoamento, de 180 horas e certificação pela Pró-Reitoria de Extensão Universitária (PROEX) da UNESP. A técnica e os instrumentos de pesquisa utilizados foram: o grupo dialogal, o questionário e a filmagem. A análise de dados foi orientada pela análise de conteúdo e evidenciou o papel ativo dos sujeitos da pesquisa na produção de conhecimentos. Como resultados alcançados constatamos um contexto de escolas marcado por desafios de natureza administrativa e pedagógica. Não há processos formativos oferecidos aos Coordenadores, via sistema municipal, centrados nas concepções da Educação Integral e da Escola de Tempo Integral e que os auxiliem nas necessidades formativas emanadas na escola. Portanto, é necessária a formação que os sustente no desempenho do papel de formador de professor e no fortalecimento de sua identidade profissional, que se mostrou fragilizada. Para que esses profissionais se percebam e se reconheçam como formadores de professores da/na Educação Básica é necessário aprimorar seu campo de atuação, criando mecanismos de interação coletiva e colaborativa que os auxilie na detecção dos problemas que surgem nas práticas educativas. Constatou-se a precarização das condições de trabalho (falta de profissionais/infraestrutura) para o atendimento dos alunos em novos tempos e espaços educativos; a precarização documental e legal acerca da Educação Integral e da Escola de Tempo Integral. Propomos a revisão dessas questões, bem como a consolidação de uma Política Pública de Estado no município para as escolas com jornada ampliada, como também uma Política de Formação Continuada voltada aos Coordenadores, que possuem a função legalmente constituída, mas ainda carecem de maior reconhecimento profissional e de valorização que os assegure em seus processos de desenvolvimento profissional. / This study was developed within the research line “Education Professionals Formation, Educational Policies and the Public School”, of the Post-Graduate Program in Education of the Faculdade de Ciências e Tecnologia da Universidade Estadual Paulista UNESP/Presidente Prudente’s campus. Investigated the actions directed to the continued formation and to the performance of the Pedagogical Coordinators in Elementary Schools from the Public-School System in Araçatuba City, specifically, the full-time and complementary activity public schools. The analysis rests on the conceptions about the formation of these professionals, understood by us as teacher’s formers in basic education (RINALDI, 2009), and on relevant challenges to its practice in this complex process of implementing a 'new school model' still under construction in the city. It is a derivative project of the proposal “Teacher’s Formation and the Full Time School: Policies, Practices and Challenges" (FAPESP 2014/14750-4). Adopts qualitative research in education from an interpretative theoretical matrix (PACHECO, 1995), which we seek to understand the professional learning process of pedagogical coordinators acting in this schools, from their participation in a continuing education program considering its performance, knowledge and everyday demands. It was developed through bibliographical, documentary and data collection research, through empirical work, guided by the constructive-collaborative perspective (COLE; KNOWLES, 1993), of intervention research. Participated 7 pedagogical coordinators from 5 schools. The data collection was through the development of a continuous training course, in the modality of improvement, lasting 180 hours and certification by the Pro-Rectory of University Extension (PROEX) of UNESP. The technique and the research instruments used in this process were: the dialog group, the questionnaire and the filming. The data analysis was guided by the content analysis and evidenced the active role of the subjects of this research in the production of knowledge. As results achieved we find a school context marked by administrative and pedagogical challenges. There are no training processes offered to the Coordinators, through the Municipal Education System, focusing on the concepts of Full-time Education and the Full-Time Schools and that help them with the training needs emanated in the school. Therefore, it is necessary a training that supports them in the role of teacher’s trainers and in the strengthening of their professional identity, which has been weakened. In order for these professionals to perceive and recognize themselves as teacher’s trainers of the Basic Education, it is necessary to improve their field of action, seeking mechanisms of collective and collaborative interaction to expand their capacities in the detection of problems that arise in educational practices. It was observed the precariousness of working conditions (lack of professionals and infrastructure) for the care of students in new times and educational spaces; the documentary and legal precariousness about Full-time Education and the Full-Time Schools. We propose a revision on these subjects, as well as the consolidation of a Public Policy of State in the municipality for the schools with extended hours, as well as a Policy of Continuous Formation aimed to Coordinators, who have the legally constituted function, but still need more professional recognition and valuation that assures them in their professional development processes.