La historia de la ciencia como herramienta para la enseñanza de física en secundaria : un ejemplo en calor y temperatura

In this work we suggest and analyze some stages of a course on heat and temperature which knowledge of the past of the ideas and the solution provided can enable a better understanding of the content. The hypothesis that guided the planning of activities was that the scientific content studied throughout its history comes closer to the cognitive universe, not only of the student, but of man himself

La historia de la ciencia como herramienta para la enseñanza de física en secundaria: un ejemplo en calor y temperatura

In this work we suggest and analyze some stages of a course on heat and temperature which knowledge of the past of the ideas and the solution provided can enable a better understanding of the content. The hypothesis that guided the planning of activities was that the scientific content studied throughout its history comes closer to the cognitive universe, not only of the student, but of man himself

Zero-point Divacancy Concentration in the Shadow Wave-Function Model for Solid 4He

We address the issue of interaction between zero-point vacancies in solid 4He as described within the shadow wave-function model. Applying the reversible-work method and taking into account finite-size effects, we obtain a zero-point monovacancy concentration of (2.03 +- 0.02) 10^{-3}, which is slightly higher than the result due to Reatto et al. for the same model. Utilizing the same methodology, we then consider the divacancy, taking into account both the in-plane as well as out-of-plane configurations with respect to the basal plane. We find no significant anisotropy between both conformation. Furthermore, although there is a small binding tendency, the expected divacancy concentration is only ~4-5 times larger than the value expected in the absence of any clustering propensity, 2.5 10^{-5}. This result suggests that, within the employed model description, no vacancy aggregation leading to phase separation is to be expected in the ground state.Comment: 10 pages, 1 figur

Efeito das variações de pH e temperatura sobre as antocianinas na polpa de açaí: estudos espectrofotométricos e cromatográficos.

bitstream/CNPDIA-2009-09/11841/1/CT78_2006.pd

Textile effluente treatment though oxidation via activated humidity

Diversos problemas envolvem as estações de tratamento de efluentes têxteis, principalmente o baixo nível de eficiência quanto a remoção da cor. Em função de normas mais rigorosas que estão sendo estabelecidas, as indústrias têxteis têm que encontrar métodos efetivos para a descoloração de seus efluentes. O presente trabalho investigou através de estudos em laboratório, a remoção de cor destes efluentes através da oxidação por via úmida ativada (Processo de Oxidação Avançada-AOP) utilizando como oxidante o peróxido de hidrogênio, ativado pela radiação ultravioleta. A fotodegradação foi realizada em batelada em um reator equipado com uma lâmpada de vapor de mercúrio de média pressão, de imersão. Três diferentes doses de peróxido de hidrogênio foram testadas (15, 30 e 45 mg/L) em amostras com diferentes pHs (3, 7 e 11). A degradação da cor mostrou seguir uma cinética de pseudo primeira ordem, sendo as condições mais adequadas para o pH alcalino, na presença de 45 mg/L de H2O2.Several problems are found in the textile effluent treatment stations, mainly the low level of efficiency concerning color removal. As a result of more rigorous standards that have been established the textile industries are forced to find effective methods for discoloration of their effluents. This work concerns a laboratory investigation on the removal of color from these effluents through oxidation by activated wet process, (Advanced Oxidation Process-OAP), using hydrogen peroxide as an oxidizing agent, activated by ultraviolet radiation. Photo-degradation was carried out in a bark in a reactor equipped with an immersion mercury vapor lamp at medium pressure. Three different dosages of hydrogen peroxide were tested (15, 30 and 45 mg/L) using samples with different pHs (3, 7, 11). Color degradation proved to follow a kinetics of pseudo first order, being the most appropriate conditions for an alkaline pH, in the presence of 45 mg/L of H2O2

The subjective body of nursing academic: dimensions of sensoperception

Objetivo: identificar a maneira como acadêmicos de enfermagem visualizam o próprio corpo a partir do tato. Metodologia: estudo descritivo, de abordagem qualitativa com destaque para a subjetividade, feito com 33 alunos de graduação em enfermagem da Universidade Federal do Rio Grande do Norte/UFRN. Resultados: as respostas obedecem a um roteiro céfalo-caudal frente a um modelo anatomicamente incorporado para o exame físico. Os acadêmicos manifestaram gostar das partes que se situam na cabeça, tronco e não gostar daquelas referentes aos membros inferiores configurando um esquema corporal idealizado frente um corpo concreto e não aceito, embora tenha que conviver com o mesmo. Conclusão: mediante o estudo foi possível avaliar o quão importante é a relação desses estudantes com seu corpo e sua influência de cunho psicossocial e, ainda num sentido projetivo reflete a relação frente ao corpo dos portadores de transtornos mentais e comportamentais, objeto do seu cuidado

Microstructure and paramagnetic Meissner effect of YBa2Cu3Oy nanowire networks

The microstructure and magnetic characterizations of non-woven, fabric-like YBa2Cu3Oy (YBCO) nanofiber mats are reported. The samples were produced by solution blow spinning (SBS), starting from a sol-gel solution of the precursor materials in polyvinylpyrrolidone. In the present work, the nanowire network samples were morphologically characterized by scanning electron microscopy, and the superconducting properties were measured by magnetometry. An interesting feature is the appearance of a paramagnetic Meissner effect (PME) when field-cooling, firstly verified in that sort of sample. The PME appears only in very small applied magnetic fields, which is similar to previous observations of the PME on an artificially granular YBCO thin film, but distinctly different from bulk samples investigated in the literature. Thus, we explain the PME by flux trapping within the voids of the nanoporous structure of the nanofiber mats