A escola como espaço formador de professores: um estudo sobre interações e possibilidades do exercício da docência

A experiência de uma escola localizada na periferia da Baixada Fluminense em que os desafios do cotidiano mobilizam os docentes para a construção coletiva do PPP (Projeto Político Pedagógico), suscitou a realização desse trabalho. A presente pesquisa investigou as possíveis relações que se estabelecem entre a formação continuada construída na escola e a mobilização dos saberes dos docentes, como caminho para elaboração de um PPP emancipador. Tem-se como referencial teórico: 1- As contribuições de Nóvoa sobre a escola como lócus privilegiado de formação docente, construtor de novos entendimentos acerca dos processos educativos e da profissionalização docente, 2- As análises de Contreras sobre a autonomia docente e a necessidade da reflexão dos docentes sobre o sentido político que orienta as suas ações 3- O reconhecimento da elaboração de saberes pelos docentes na constituição de seu trabalho e a necessidade de uma nova epistemologia da profissão com foco na interação humana em acordo a Tardif. Buscou-se desvelar a concepção de formação continuada presente, apreender os significados deste processo pelos professores desta escola e suas repercussões no trabalho docente. Tratou-se de um estudo de caso de cunho etnográfico aplicado à Educação, de abordagem metodológica qualitativa, estruturado em pesquisa bibliográfica, observações das reuniões de formação continuada, análise documental, relatos orais e entrevistas semi-estruturadas individuais. Indagou-se aos professores sobre as características da proposta de formação continuada da escola, sua organização, gestão e os efeitos sobre o trabalho cotidiano. As análises permitiram constatar alguns elementos que definem as características dessa escola: busca pela gestão democrática, trabalho interativo docente e as repercussões desses processos na constituição do PPP, pautados no compromisso com os alunos e a comunidade. Dessa forma, destaca-se a importância de se considerar a escola como lócus significativo de formação continuada, pois é a instância onde os professores constroem, reconstroem, mobilizam, manifestam e interagem vários saberes que permitirão a especificidade, a significação e a atribuição dos sentidos de sua ação docente, passando a constituir sua profissionalidade

Caracterização e pirólise de arenitos asfálticos oriundos da Formação Pirambóia, Bacia do Paraná: avaliação da viabilidade para produção de óleo

Neste trabalho, algumas caracterizações químicas foram realizadas em arenitos asfálticos da região de Piracicaba-SP, Formação Piramboia da Bacia do Paraná, para verificar seu potencial de produção de óleo. Para isso, as amostras obtidas da região foram submetidas a avaliação por termogravimetria, teor de umidade, teor de cinzas, teor de material orgânico por extração, pirólise, análise elementar e fracionamento em coluna. Por TGA observou-se que a 500 C praticamente todo material orgânico presente sofreu pirólise. A extração colaborou para se obter a classificação das amostras quanto ao teor de material orgânico, apresentando entre 4 e 13%, sendo que pelos teores encontrados a amostra AM06 é considerada de alto potencial produtivo, as amostras AM05, AM08 e AM09 são de médio, as amostras AM01, AM02, AM03 e AM07 possuem baixo, mas ainda atrativo, e a AM04 não possui atratividade. Pela avaliação elementar, a relação H/C e O/C dos extratos evidenciaram que algumas amostras estão no processo final da diagênese e outras no início da catagênese, indicando que elas estão no processo inicial de maturação. A avaliação cromatográfica dos extratos revelou que houve perdas de óleo por intemperismo restando majoritariamente compostos de alto peso molecular. O fracionamento permitiu verificar que as amostras AM01, AM06 e AM09 possuem maior quantidade de hidrocarbonetos livres e as amostras AM06 e AM07 e AM09 apresentaram maior teor de óleo. O procedimento de pirólise evidenciou que as amostras AM01, AM05, AM06 e AM09 apresentam maior potencial de geração de óleo, sendo que a faixa encontrada de óleo pirolítico ficou entre 2 e 8%, e através de avaliação por CGAR e CGAR-EM observou-se que ela promove a liberação de quantidades consideráveis de substâncias mais leves do que quando comparados aos extratos obtidos diretamente nas amostras originais. Além de produzir uma série homóloga de hidrocarbonetos parafínicos e olefínicos. A comparação dos produtos de pirólise dos arenitos com os produtos de pirólise de um resíduo de vácuo por CGAR-EM permitiu observar que existe similaridade entre suas composições, onde o processo de pirólise do resíduo de vácuo gera uma série homóloga de hidrocarbonetos entre C10 a C32, similar aos produtos de pirólise da amostra AM09, porém com menor variedade de tipos de hidrocarbonetos. A pré-avaliação da co-pirólise dos arenitos com resíduos plásticos indicou que é possível aumentar a geração de líquidos, porém é necessário mais estudo para afirmações inequívocas. Com base nos resultados das avaliações realizadas podemos concluir que a região apresenta na sua maioria potencial interessante para produção de óleo utilizando pirólise

A função psicalisante como condição de singularidade em uma experiência política de desinstitucionalização

Essa tese apresenta alguns momentos de uma experiência na operação da função política de assessoria de desinstitucionalização na gestão pública da saúde mental da cidade do Rio de Janeiro. Essa função teve como tarefa o planejamento e execução do fechamento de algumas instituições psiquiátricas de modelo manicomial, assim como o ordenamento da rede de saúde mental municipal no que tange à desinstitucionalização. Esta é entendida como a construção do projeto clínico de saída dos pacientes de iatrogênicas internações, mas também a desinstitucionalização representava nesse contexto a qualificação da direção ética e clínico-metodológica do saber e da prática na gestão da clínica da saúde mental pública. O lugar do operador da gestão foi o foco desta tese, que encontrou na posição do psicanalisante a incidência de uma direção e prática de gestão clínica mais afeitas à ética, no que diz respeito ao exercício de uma função política. A posição do psicanalisante é definida pela ocupação do sujeito do inconsciente no lugar do Outro, do trabalho, no discurso do analista, como Lacan o define. Esse é o lugar que o sujeito ocupa em trabalho, causado pela incidência do objeto a e sua propriedade de hiância, de fazer furo e singularizar um sujeito e sua prática. No discurso do analista e em sua incidência sobre o lugar ocupado pelo sujeito em trabalho o saber está barrado na ocupação do lugar da verdade, o que produz como resto um significante-mestre desbastado de seus efeitos totalitários. Demonstra-se em que momentos tal incidência ocorreu ou não. A tese que se apresenta aqui é baseada nos efeitos do objeto a, de singularização e invenção num sujeito ocupando um lugar político, portanto atravessado por essa posição do psicanalisante

Multiple-proxy lacustrine record of moisture transport over western North America from 24,000 to 12,000 YBP, Lake Estancia, New Mexico [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Pluvial Lake Estancia in central New Mexico experienced large and rapid fluctuations in surface area and elevation during the build-up to and termination of the last glacial maximum (LGM). Due to continuous groundwater discharge, a minimum pool covering about 400 square kilometers was maintained in the central basin until about 12,000 years ago, ensuring a continuous depositional sequence even during low stands of the lake. ... The sensitive response to fluctuations in climate by several independent proxies at Estancia show that transport of Pacific moisture over western North America changed dramatically during the last Ice Age, perhaps comparable to the large and rapid changes in climate documented from high-latitude ice and North Atlantic marine sediments for the LCM and its transitions.

Investigation on sanitational aspects (microbiological) of prawn processing factories

Absence of regular cleaning has been found to result in heavy bacterial loads on the surfaces of utensils and other equipment used in prawn processing factories and peeling centers. Instance of high faecal contamination is also sometimes met with. Detailed investigations have shown that a cleaning schedule comprising of treatment of these surface with a detergent followed by application of an effective disinfectant like sodium hypochlorite would prevent such bacterial build up.

Rolling of thin strip and foil: Application of a tribological model for "mixed" lubrication

A mechanical model of cold rolling of foil is coupled with a sophisticated tribological model. The tribological model treats the "mixed" lubrication regime of practical interest, in which there is "real" contact between the roll and strip as well as pressurized oil between the surfaces. The variation of oil film thickness and contact ratio in the bite is found by considering flattening of asperities on the foil and the build-up of hydrodynamic pressure through the bite. The boundary friction coefficient for the contact areas is taken from strip drawing tests under similar tribological conditions. Theoretical results confirm that roll load and forward slip decrease with increasing rolling speed due to the decrease in contact ratio and friction. The predictions of the model are verified using mill trials under industrial conditions. For both thin strip and foil, the load predicted by the model has reasonable agreement with the measurements. For rolling of foil, forward slip is overestimated. This is greatly improved if a variation of friction through the bite is considered.

Dynamics in dye-doped LC systems in presence of trans-cis isomerism

The excitation as well as relaxation dynamics of dye-doped nematic liquid crystal cells has been explored both experimentally and theoretically. Overshoots in the build up of the probe signal diffracted from gratings written onto dye-doped liquid crystal systems have often been observed. The overshoot behaviour makes the accurate measurement of nonlinear optical (NLO) response magnitude difficult and ambiguous. Moreover, it complicates the understanding of the dynamics and the physics of the NLO processes. On the basis of the system with trans-cis isomerisation as a mechanism of the NLO effect the quantitative model has been built to describe the experimental results which we observe. The two unknown material parameters: diffusion coefficient and cis species lifetime are calculated from the relaxation data. A quantitative model of the signal build-up uses these parameters. The calculated dynamic behaviour based on this model correlates very well with the experimental data. The model is used to predict the performance of the system with various dopant diffusion properties.

Near-complete transuranic waste incineration in a thorium fuelled pressurised water reactor

The production of long-lived transuranic (TRU) waste is a major disadvantage of fission-based nuclear power. Incineration, and virtual elimination, of waste stockpiles is possible in a thorium (Th) fuelled critical or subcritical fast reactor. Fuel cycles producing a net decrease in TRUs are possible in conventional pressurised water reactors (PWRs). However, minor actinides (MAs) have a detrimental effect on reactivity and stability, ultimately limiting the quality and quantity of waste that can be incinerated. In this paper, we propose using a thorium-retained-actinides fuel cycle in PWRs, where the reactor is fuelled with a mixture of thorium and TRU waste, and after discharge all actinides are reprocessed and returned to the reactor. To investigate the feasibility and performance of this fuel cycle an assembly-level analysis for a one-batch reloading strategy was completed over 125 years of operation using WIMS 9. This one-batch analysis was performed for simplicity, but allowed an indicative assessment of the performance of a four-batch fuel management strategy. The build-up of 233U in the reactor allowed continued reactive and stable operation, until all significant actinide populations had reached pseudo-equilibrium in the reactor. It was therefore possible to achieve near-complete transuranic waste incineration, even for fuels with significant MA content. The average incineration rate was initially around 330 kg per GW th year and tended towards 250 kg per GW th year over several decades: a performance comparable to that achieved in a fast reactor. Using multiple batch fuel management, competitive or improved end-of-cycle burn-up appears achievable. The void coefficient (VC), moderator temperature coefficient (MTC) and Doppler coefficient remained negative. The quantity of soluble boron required for a fixed fuel cycle length was comparable to that for enriched uranium fuel, and acceptable amounts can be added without causing a positive VC or MTC. This analysis is limited by the consideration of a single fuel assembly, and it will be necessary to perform a full core coupled neutronic-thermal-hydraulic analysis to determine if the design in its current form is feasible. In particular, the potential for positive VCs if the core is highly or locally voided is a cause for concern. However, these results provide a compelling case for further work on concept feasibility and fuel management, which is in progress. © 2011 Elsevier Ltd. All rights reserved.

Centrifugal modelling of the landslides triggering mechanism in layered fill slopes

Concerns over loosely compacted fill slopes stability in Hong Kong arouse in the past few decades, since the Sau Mau Ping disasters in 1972 and 1976. Research conducted on loose fill slopes in the past few years aimed to understand the failure mechanisms of a loosely compacted fill slope. Recently, layering effect has been hypothesised to be a possible condition in the fill slopes leading to a fast flowslide triggered by a rise of water table. Centrifuge experiments were conducted to investigate the layering effect on a model granular slope and hence to determine the triggering mechanisms of seepage induced slope failure. Test results showed that slope failure can be easily triggered in layered fill model slopes when seepage is restricted and localised pore water pressure is allowed to build up within the slope. © 2006 Taylor & Francis Group, London.

Numerical analysis of thermally actuated magnets for magnetization of superconductors

Superconductors, such as YBCO bulks, have extremely high potential magnetic flux densities, comparing to rare earth magnets. Therefore, the magnetization of superconductors has attracted broad attention and contribution from both academic research and industry. In this paper, a novel technique is proposed to magnetize superconductors. Unusually, instead of using high magnetic fields and pulses, repeatedly magnetic waves with strength of as low as rare earth magnets are applied. These magnetic waves, generated by thermally controlling a Gadolinium (Gd) bulk with a rare earth magnet underneath, travel over the flat surface of a YBCO bulk and get trapped little by little. Thus, a very small magnetic field can be used to build up a very large magnetic field. In this paper, the modelling results of thermally actuated magnetic waves are presented showing how to transfer sequentially applied thermal pulses into magnetic waves. The experiment results of the magnetization of YBCO bulk are also presented to demonstrate how superconductors are progressively magnetized by small magnetic field © 2010 IOP Publishing Ltd.

Magnetization of bulk superconductors using thermally actuated magnetic waves

A novel technique is proposed to magnetize bulk superconductors, which has the potential to build up strong superconducting magnets. Instead of conventionally using strong magnetic pulses, periodical magnetic waves with strength as low as that of rare-earth magnets are applied. These magnetic waves travel from the periphery to the center of a bulk superconductor and become trapped little by little. In this way, bulk superconductors can gradually be magnetized. To generate these magnetic waves, a thermally actuated magnet was developed, which is constructed by a heating/cooling switch system, a rare-earth bulk magnet, and a Gadolinium (Gd) bulk. The heating/cooling switch system controls the temperature of the Gd bulk, which, along with the rare-earth magnet underneath, can transform thermal signals into magnetic waves. The modeling results of the thermally actuated magnet show that periodical magnetic waves can effectively be generated by applying heating and cooling pulses in turn. A YBCO bulk was tested in liquid nitrogen under the magnetic waves, and a notable accumulation of magnetic flux density was observed. © 2006 IEEE.

Soft ferrite used as thermal-magnetic conversion intermedium in the flux pumping technology

Recent progress in material science has proved that high-temperature superconductors, such as bulk melt-processed yttrium barium copper oxide (YBCO) single domains, have a great potential to trap significant magnetic fields. In this paper, we will describe a novel method of YBCO magnetization that only requires the applied field to be at the level of a permanent magnet. Instead of applying a pulsed high magnetic field on the YBCO, a thermally actuated material (TAM), such as Mg0.15}hbox{Cu}0.15} hbox{Zn0.7 Ti0.04}Fe1.96boxO4, has been used as an intermedium to create a travelling magnetic field by changing the local temperature so that the local permeability is changed to build up the magnetization of the YBCO gradually after multiple pumping cycles. It is well known that the relative permeability of ferrite is a function of temperature and its electromagnetic properties can be greatly changed by adding dopants such as Mg or Ti; therefore, it is considered to be the most promising TAM for future flux pumping technology. Ferrite samples were fabricated by means of the conventional ceramic method with different dopants. Zinc and iron oxides were used as raw materials. The samples were sintered at 1100 C, 1200 C} , and 1300 C. The relative permeability of the samples was measured at temperatures ranging from 77 to 300 K. This work investigates the variation of the magnetic properties of ferrites with different heat treatments and doping elements and gives a smart insight into finding better ferrites suitable for flux pumping technology. © 2002-2011 IEEE.

A sustainable PWR fuel cycle with complete TRU recycling using fertile-free fuel

The feasibility of a conventional PWR fuel cycle with complete recycling of TRU elements in the same reactor is investigated. A new Combined Non-fertile and Uranium (CONFU) fuel assembly where about 20% of the uranium fuel pins are replaced with fertile free fuel (FFF) hosting TRU generated in the previous cycle is proposed. In this sustainable fuel cycle based on the CONFU fuel assembly concept, the amount and radiotoxicity of the nuclear waste can be significantly reduced in comparison with the conventional once-through UO 2 fuel cycle. It is shown that under the constraints of acceptable power peaking limits, the CONFU assembly exhibits negative reactivity feedback coefficients comparable in values to those of the reference UO2 fuel. Moreover, the effective delayed neutron fraction is about the same as for UO2-fueled cores. Therefore, feasibility of the PWR core operation and control with complete TRU recycle has been shown in principle. However, gradual build up of small amounts of Cm and Cf challenges fuel reprocessing and fabrication due to the high spontaneous fissions rates of these nuclides and heat generation by some Pu, Am, and Cm isotopes. Feasibility of the processing steps becomes more attainable if the time between discharge and reprocessing is 20 years or longer. The implications for the entire fuel cycle will have to be addressed in future studies.

A parametrically excited vibration energy harvester

In the arena of vibration energy harvesting, the key technical challenges continue to be low power density and narrow operational frequency bandwidth. While the convention has relied upon the activation of the fundamental mode of resonance through direct excitation, this article explores a new paradigm through the employment of parametric resonance. Unlike the former, oscillatory amplitude growth is not limited due to linear damping. Therefore, the power output can potentially build up to higher levels. Additionally, it is the onset of non-linearity that eventually limits parametric resonance; hence, this approach can also potentially broaden the operating frequency range. Theoretical prediction and numerical modelling have suggested an order higher in oscillatory amplitude growth. An experimental macro-sized electromagnetic prototype (practical volume of ∼1800 cm3) when driven into parametric resonance, has demonstrated around 50% increase in half power band and an order of magnitude higher peak power density normalised against input acceleration squared (293 μW cm-3 m-2 s4 with 171.5 mW at 0.57 m s-2) in contrast to the same prototype directly driven at fundamental resonance (36.5 μW cm-3 m-2 s4 with 27.75 mW at 0.65 m s-2). This figure suggests promising potentials while comparing with current state-of-the-art macro-sized counterparts, such as Perpetuum's PMG-17 (119 μW cm-3 m-2 s4). © The Author(s) 2013.

Carrier transport assisted by dopants in doped poly(N-vinylcarbozole) light-emitting diodes

We have investigated the transient electroluminescence (EL) onset of the double-layer light-emitting devices made from poly(N-vinylcarbozole) (PVK) doped with 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) and tris(8-hydroxy-quinoline) aluminium (Alq(3)). For the double-layered device in which PVK was doped with 0.1 wt% DCJTB, the EL onset of PVK lags that of DCJTB and Alq(3), while the EL onset of DCJTB and Alq(3) is simultaneous. However, the EL emission of the double-layered device of PVK/Alq(3) originates only from Alq(3). The results show that DCJTB dopants can not only help to tunnel electrons from Alq(3) zone to PVK but can also assist electrons transfer in PVK under high electric field by hopping between DCJTB molecules or from DCJTB to PVK sites at a low doping concentration of 0.1 wt%. When the DCJTB doping concentration is 4.0 wt%, the EL onset of Alq(3) lags that of DCJTB. The difference in the EL onsets of DCJTB, Alq(3) and PVK is attributed to the slow build-up of the internal space charge in the vicinity of the interface between PVK and Alq(3). The electron potential difference of the interface between Alq(3) and PVK doped by DCJTB can be adjusted by changing the DCJTB doping concentration in double-layer devices.