Síntese e processamento de pentóxido de nióbio e óxidos mistos de nióbio e titânio nanoparticulados e estudo de suas propriedades fotocatalíticas

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Ciência e Engenharia de Materiais, Florianópolis, 2017.Neste trabalho, inicialmente, foi realizado um estudo detalhado de uma nova rota de síntese via sol-gel coloidal para a obtenção de Nb2O5 e óxidos mistos de Nb2O5:TiO2. Foram controlados parâmetros como temperatura, relação molar H+:Nb5+, H+:(Nb5+:Ti4+) e Nb5+:H2O para determinar as melhores condições de síntese. Os resultados obtidos indicam que a síntese sol-gel coloidal é um método adequado para a obtenção de Nb2O5 e óxidos mistos (Nb2O5:TiO2) tal como sol nanoparticulado estável ou como pó nanométrico. Nanopartículas amorfas com tamanho médio de 20 nm (Nb2O5) e 10 nm (Nb2O5:TiO2) foram obtidas controlando as variáveis da síntese. O processo de tratamento térmico realizado nas nanopartículas de Nb2O5 promoveu a formação de diferentes fases cristalinas (TT e T) com estrutura pseudohexagonal e ortorrômbica, respectivamente, que a temperaturas mais elevadas se transformam em uma mistura de fases ortorrômbica e monoclínica. No caso dos óxidos mistos (Nb2O5:TiO2), a calcinação entre 650 e 800 ºC levou à formação de diferentes fases cristalinas, entre elas TiNb2O7 como principal. Nos dois óxidos (Nb2O5 e Nb2O5:TiO2), a composição da fase cristalina apresentou influência significativa na atividade fotocatalítica. No caso do Nb2O5 puro, o melhor desempenho fotocatalítico foi observado para o material constituído principalmente pela fase TT-Nb2O5, enquanto que, para o óxido misto, o melhor desempenho é encontrado no material constituído principalmente pela fase monoclínica-TiNb2O7. Em uma segunda etapa do trabalho, a fim de avaliar a influência de diferentes métodos de síntese na obtenção de nanopartículas, um novo método hidrotérmico assistido por micro-ondas foi utilizado para preparar nanopartículas de Nb2O5. Os resultados obtidos indicam que o processo por micro-ondas a 180 °C durante 20 min foi suficiente para obter nanopartículas amorfas com um tamanho médio de 40 nm. As nanopartículas obtidas apresentaram um processo similar de cristalização ao observado nas amostras preparadas pela síntese sol-gel, demonstrando também, nesse caso, que a cristalinidade teve efeito significativo na atividade fotocatalítica do material. Em uma terceira etapa deste trabalho, filmes finos foram preparados pelo método de dip-coating. Experimentos fotocatalíticos confirmaram que os filmes finos constituídos pela fase TT-Nb2O5 são promissores para aplicações como catalisadores imobilizados em reações fotoativas.Abstract : A detailed study of a novel synthesis via colloidal sol-gel route for obtaining nanoparticulate Nb2O5 and mixed oxides Nb2O5: TiO2 was investigated in this work. Parameters such as temperature and H+:Nb5+ and H+:(Nb5+: Ti4+), Nb5+: H2O molar ratio were controlled in order to determine the best synthesis conditions. The obtained results indicate that the colloidal sol-gel synthesis is a good alternative for obtaining Nb2O5 and mixed oxides (Nb2O5: TiO2) either as stable nanoparticulate sol or as a nanosized powder. Amorphous nanoparticles with an average size of 20 nm (Nb2O5) and 10 nm (Nb2O5:TiO2) were produced by controlling the synthesis variables. The heat treatment process performed on Nb2O5 nanoparticles promoted the formation of different crystalline phases (TT and T) with pseudo-hexagonal and orthorhombic structures, respectively, that transform at higher temperatures in a mixture of orthorhombic and monoclinic phases. In the case of mixed oxides (Nb2O5: TiO2), the calcination at temperatures between 650 and 800 ºC, led to the formation of different crystalline phases, among them TiNb2O7 as the major one. In the two systems (Nb2O5 and Nb2O5: TiO2), the crystalline phase composition was found to have a significant influence on the photocatalytic activity. In the case of pure Nb2O5, the best photocatalytic performance was observed for the material mainly constituted by the TT-Nb2O5 phase, whereas for the mixed oxide the best performance was found for the material mainly constituted by the monoclinic-TiNb2O7 phase. In a second stage of the work, in order to evaluate the influence of different synthesis methods in obtaining nanoparticles, a new microwave-assisted hydrothermal method was used to prepare nanoparticles of Nb2O5. The results indicate that the microwave procedure at 180 °C for 20 min was enough to obtain amorphous nanoparticles with average sizes of 40 nm. The nanoparticles produced showed a similar crystallization process to those observed in the samples prepared by the sol-gel synthesis, and also in crystallinity had a significant effect on the photocatalytic activity of the material. In a third stage of this work, thin films were prepared by the dip-coating method. Photocatalytic experiments confirmed that the thin films constituted by the TT-Nb2O5 phase are promising for applications as catalysts immobilized in photoactived reactions

Laser-Stimulated Fluorescence in Paleontology

Fluorescence using ultraviolet (UV) light has seen increased use as a tool in paleontology over the last decade. Laser-stimulated fluorescence (LSF) is a next generation technique that is emerging as a way to fluoresce paleontological specimens that remain dark under typical UV. A laser’s ability to concentrate very high flux rates both at the macroscopic and microscopic levels results in specimens fluorescing in ways a standard UV bulb cannot induce. Presented here are five paleontological case histories that illustrate the technique across a broad range of specimens and scales. Novel uses such as back-lighting opaque specimens to reveal detail and detection of specimens completely obscured by matrix are highlighted in these examples. The recent cost reductions in medium-power short wavelength lasers and use of standard photographic filters has now made this technique widely accessible to researchers. This technology has the potential to automate multiple aspects of paleontology, including preparation and sorting of microfossils. This represents a highly cost-effective way to address paleontology's preparatory bottleneck.published_or_final_versio

A Comprehensive Analysis of Electric Dipole Moment Constraints on CP-violating Phases in the MSSM

We analyze the constraints placed on individual, flavor diagonal CP-violating phases in the minimal supersymmetric extension of the Standard Model (MSSM) by current experimental bounds on the electric dipole moments (EDMs) of the neutron, Thallium, and Mercury atoms. We identify the four CP-violating phases that are individually highly constrained by current EDM bounds, and we explore how these phases and correlations among them are constrained by current EDM limits. We also analyze the prospective implications of the next generation of EDM experiments. We point out that all other CP-violating phases in the MSSM are not nearly as tightly constrained by limits on the size of EDMs. We emphasize that a rich set of phenomenological consequences is potentially associated with these generically large EDM-allowed phases, ranging from B physics, electroweak baryogenesis, and signals of CP-violation at the CERN Large Hadron Collider and at future linear colliders. Our numerical study takes into account the complete set of contributions from one- and two-loop EDMs of the electron and quarks, one- and two-loop Chromo-EDMs of quarks, the Weinberg 3-gluon operator, and dominant 4-fermion CP-odd operator contributions, including contributions which are both included and not included yet in the CPsuperH2.0 package. We also introduce an open-source numerical package, 2LEDM, which provides the complete set of two-loop electroweak diagrams contributing to the electric dipole moments of leptons and quarks.Comment: 23 pages, 11 figures; v2: references added, minor change

PROFESSIONAL SKILLS DEMANDED OF ACCOUNTANTS: ADEQUACY OF THE ACTIVITIES DEVELOPED DURING TRAINING PERIODS

Esta pesquisa teve como objetivo geral investigar se o estágio curricular e/ou extracurricular colabora para o desenvolvimento das competências, ou seja, conhecimento, vivência de práticas operacionais e atitudes demandadas pelo mercado de trabalho aos futuros profissionais da área de contabilidade. Esta pesquisa se faz respeitável por haver poucas análises no campo contábil abordando o desenvolvimento de competências profissionais. Para efetivação desta pesquisa, foi realizado um estudo de campo com 160 estudantes do curso de Ciências Contábeis de seis estabelecimentos de ensino superior da Região Metropolitana de Recife, com o auxílio de um questionário aplicado diretamente a graduandos de Ciências Contábeis que faziam ou já tinham feito estágio na área contábil, ou em áreas afins. As descobertas da pesquiva demonstraram que as organizações estão escolhendo estagiários para auxiliar nos campos relativos ao curso, pois 70% dos graduandos confirmaram desenvolver ou desenvolveram durante algum estágio funções relacionadas com sua área de formação. Os dados obtidos pela pesquisa evidenciam os conhecimentos contemplados como os "totalmente adquiridos". São eles: administração fiscal (13%), tesouraria (8%), planejamento financeiro (4%) e custos (4%), ou seja, conhecimentos relacionados à experiência da atividade contábil e áreas afins. Os resultados da pesquisa de campo confirmam: os alunos entrevistados possuem maior argúcia de desenvolvimento durante os estágios através de atitudes. Os dados dessa pesquisa sugerem a contribuição da atividade de estágio curricular e/ou extracurricular, desenvolvimento das competências profissionais exigidas pelo mercado de trabalho, pelo menos na percepção dos alunos de graduação do curso de ciências contábeis.This research aimed to investigate whether the general curricular and / or extracurricular activities contribute to competence development, ie, knowledge, experience, operational practices and attitudes demanded by the labor market for future accounting professionals. This research is respected for having few book reviews in the field addressing the development of professional skills. For the realization of this research a field study was conducted with 160 students studying accounting in six higher educational institutions in the metropolitan area of Recife, by the application of a questionnaire directly to the Accounting graduates who did or had done a curricular or extracurricular training program in accounting or related areas. The findings showed that organizations are choosing to trainees to assist in fields related to their course, since 70% of the students confirmed that they were developing or developed during their training period functions related to their area of study. The data obtained from the study highlight the knowledge referred to as "fully acquired". They include: fiscal administration (13%), treasury (8%), financial planning (4%) and cost analysis (4%), ie, knowledge related to the experience of accounting activity and related areas. The survey results from the field confirm: students interviewed have more astuteness for development during the training period through their attitudes. Likewise, the data from this study suggest the contribution of curricular and / or extracurricular activity, for the development of professional skills required by the labor market, at least in the perception of the undergraduate students of the course in accounting.

Accidental Outcomes Guide Punishment in a “Trembling Hand” Game

How do people respond to others' accidental behaviors? Reward and punishment for an accident might depend on the actor's intentions, or instead on the unintended outcomes she brings about. Yet, existing paradigms in experimental economics do not include the possibility of accidental monetary allocations. We explore the balance of outcomes and intentions in a two-player economic game where monetary allocations are made with a “trembling hand”: that is, intentions and outcomes are sometimes mismatched. Player 1 allocates $10 between herself and Player 2 by rolling one of three dice. One die has a high probability of a selfish outcome, another has a high probability of a fair outcome, and the third has a high probability of a generous outcome. Based on Player 1's choice of die, Player 2 can infer her intentions. However, any of the three die can yield any of the three possible outcomes. Player 2 is given the opportunity to respond to Player 1's allocation by adding to or subtracting from Player 1's payoff. We find that Player 2's responses are influenced substantially by the accidental outcome of Player 1's roll of the die. Comparison to control conditions suggests that in contexts where the allocation is at least partially under the control of Player 1, Player 2 will punish Player 1 accountable for unintentional negative outcomes. In addition, Player 2's responses are influenced by Player 1's intention. However, Player 2 tends to modulate his responses substantially more for selfish intentions than for generous intentions. This novel economic game provides new insight into the psychological mechanisms underlying social preferences for fairness and retribution

Dual Erb B Inhibition in Oesophago-gastric Cancer (DEBIOC): A phase I dose escalating safety study and randomised dose expansion of AZD8931 in combination with oxaliplatin and capecitabine chemotherapy in patients with oesophagogastric adenocarcinoma

Background: AZD8931 has equipotent activity against epidermal growth factor receptor, erbB2, and erbB3. Primary objectives were to determine the recommended phase II dose (RP2D) of AZD8931 + chemotherapy, and subsequently assess safety/preliminary clinical activity in patients with operable oesophagogastric cancer (OGC). Methods: AZD8931 (20 mg, 40 mg or 60 mg bd) was given with Xelox (oxaliplatin + capecitabine) for eight 21-day cycles, continuously or with intermittent schedule (4 days on/3 off every week; 14 days on/7 off, per cycle) in a rolling-six design. Subsequently, patients with OGC were randomised 2:1 to AZD8931 + Xelox at RP2D or Xelox only for two cycles, followed by radical oesophagogastric surgery. Secondary outcomes were safety, complete resection (R0) rate, six-month progression-free survival (PFS) and overall survival. Results: During escalation, four dose-limiting toxicities were observed among 24 patients: skin rash (1) and failure to deliver 100% of Xelox because of treatment-associated grade III-IV adverse events (AEs) (3: diarrhoea and vomiting; vomiting; fatigue). Serious adverse events (SAE) occurred in 15 of 24 (63%) patients. RP2D was 20-mg bd with the 4/3 schedule. In the expansion phase, 2 of 20 (10%) patients in the Xelox + AZD8931 group and 5/10 (50%) patients in the Xelox group had grade III–IV AEs. Six-month PFS was 85% (90% CI: 66%–94%) in Xelox + AZD8931 and 100% in Xelox alone. Seven deaths (35%) occurred with Xelox + AZD8931 and one (10%) with Xelox. R0 rate was 45% (9/20) with Xelox + AZD8931 and 90% (9/10) with Xelox-alone (P = 0.024). Conclusion: Xelox + AZD8931 (20 mg bd 4/3 days) has an acceptable safety profile administered as neoadjuvant therapy in operable patients with OGC. (Trial registration: EudraCT 2011-003169-13, ISRCTN-68093791)

PERCEPÇÃO DOS SERVIÇOS GERADOS PELA CONTABILIDADE EM ENTIDADES NORDESTINAS DE UTILIDADE PÚBLICA FEDERAL

Este artigo aborda a percepção dos gestores de entidades, detentoras de declaração de utilidade pública federal, localizadas no Nordeste brasileiro, relativo aos serviços gerados pela contabilidade. Inicialmente, foi realizado um levantamento no sítio do Ministério da Justiça, visando identificar quantas instituições no Nordeste possuem o título de utilidade pública federal. A pesquisa revelou a existência de 1.518 (Um mil quinhentos e dezoito) entidades, adotando como referência: outubro de 2011. Desta totalidade, somente 52 (cinquenta e duas) disponibilizaram suas prestações de contas, referentes ao exercício 2009, no sítio do Ministério público, no link cidadania. Em seguida, foi realizada uma pesquisa de opinião com os gestores de 35 (trinta e cinco) das 52 (cinquenta e duas) instituições, através de um questionário. Dentre as descobertas da investigação, verificou-se que 24 entidades possuem contabilidade interna. Conforme levantamento, os entrevistados informaram que os financiadores são bastante exigentes, principalmente o Governo. Constata-se que prestação de contas é o melhor serviço contábil, tomando como base, a relação dos prestados pela contabilidade para utilização dos usuários externos. Já a elaboração do orçamento para projetos foi o serviço mais bem avaliado, caso comparado com a utilização do mesmo para fins de controle

Tirésias: um modelo para acessibilidade ubíqua orientado à deficiência visual

Observa-se hoje um crescimento do número de dispositivos móveis disponíveis no mercado. Esses aparelhos estão cada vez mais ao alcance da população, seja pelo valor, cada vez mais acessível, bem como pela facilidade de uso. Apesar disso, esses dispositivos não estão preparados para atender pessoas com determinados tipos de deficiência, principalmente quando se trata de problemas visuais. O presente trabalho tem por objetivo propor um modelo de acessibilidade para dispositivos móveis, orientado ao suporte de pessoas que possuam algum nível de deficiência visual. Também são descritos cenários onde o modelo pode ser aplicado e o protótipo que foi desenvolvido para validá-los. Por fim, são apresentados os resultados obtidos após a execução dos cenários propostos

An isogeometric method for the Reissner-Mindlin plate bending problem

We present a new isogeometric method for the discretization of the Reissner-Mindlin plate bending problem. The proposed scheme follows a recent theoretical framework that makes possible to construct a space of smooth discrete deflections $W_h$ and a space of smooth discrete rotations \Rots_h such that the Kirchhoff contstraint is exactly satisfied at the limit. Therefore we obtain a formulation which is natural from the theoretical/mechanical viewpoint and locking free by construction

Higgs production in CP-violating supersymmetric cascade decays: probing the `open hole' at the Large Hadron Collider

A benchmark CP-violating supersymmetric scenario (known as 'CPX-scenario' in the literature) is studied in the context of the Large Hadron Collider (LHC). It is shown that the LHC, with low to moderate accumulated luminosity, will be able to probe the existing `hole' in the $m_{h_1}$-$\tan\beta$ plane, which cannot be ruled out by the LEP data. We explore the parameter space with cascade decay of third generation squarks and gluino with CP-violating decay branching fractions. We propose a multi-channel analysis to probe this parameter space some of which are background free at an integrated luminosity of 5-10 fb$^{-1}$. Specially, multi-lepton final states (3\l,\, 4\l and like sign di-lepton) are almost background free and have $5\sigma$ reach for the corresponding signals with very early data of LHC for both 14 TeV and 7 TeV center of mass energy.Comment: 24 pages, 9 figures, references added as in the journal versio