33 resultados para Intraradicular retention


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The use of wastes and industrial by-products as building materials is an important issue in order to decrease costs with waste management and the embodied energy of building products. In this study scrap tire rubber was used as additional aggregate of mortars based on natural hydraulic lime NHL 3.5 and natural sand. Different particle size fractions and proportions of scrap tire rubber were used: a mix obtained directly from industry and separated fine, medium and coarse fractions; 0 %, 18 %, 36 % and 54 % of the weight of binder, corresponding to 2.5 %, 5 % and 7.5 % of the weight of sand. As mortars based on NHL specifications became stricter with the current version of EN 459–1:2015, the influence of the rubber’s additions on the mortars’ fresh state, mechanical and physical performance is presented in this work: flow table consistency, water retention, dynamic elasticity modulus, flexural and compressive strength, open porosity and bulk density, capillary absorption, drying and thermal conductivity are studied. The use of the rubber mix coming from the waste tire industry seems advantageous and may open possibilities for use as raw material by the mortars industry.

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A presente pesquisa tem por objetivo investigar mediante observações e entrevistas as consequências da implantação de uma política inclusiva, utilizando-se de tecnologias de informação e comunicação (TIC) em uma associação assistencial. Possibilitando, através da disponibilização de computadores e programas educativos, observar o desenvolvimento do sujeito portador de condições cognitivas desfavoráveis em função de problemas associados a fatores físicos e socioeconômicos. Buscou-se com este trabalho, através de uma abordagem qualitativa de natureza aplicada, analisar quais elementos determinantes de boa absorção de conteúdos e desenvolvimento de competências estão suscetíveis a entraves, verificando-se o quanto do fator motivacional pode estar envolvido no processo, identificando formas de se trabalhar a retenção e participação dos internos da instituição. A diversidade de anseios e expectativas associadas às condições cognitivas de cada participante foi determinante para acarear as representações de grupos distintos em suas particularidades, onde cada indivíduo apresentava uma resposta diferente aos estímulos apresentados durante o processo de exposição do material educacional. Concluiu-se que a política de inclusão digital objetivando minimizar os efeitos da marginalização de um contingente esquecido pela sociedade, tem de estabelecer critérios de continuidade e diversificação, onde, além de perseguir resultados voltados ao desenvolvimento de competências, deve possibilitar momentos de ludicidade para todos os internos em associações assistenciais.

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Pharmaceuticals and personal care products (PPCPs) are widely used on a daily basis. After their usage they reach the wastewater treatment plants (WWTPs). These compounds have different physico-chemical characteristics, which makes them difficult to completely remove in the WWTPs, througth conventional treatments. Currently, there is no legislation regarding PPCPs thresholds in effluent discharge. But, even at vestigial concentrations, these compounds enclose environmental risks due to, e.g., endocrine disruption potential. There is a need of alternative techniques for their removal in WWTPs. The main goal of this work was to assess the use of electrodialytic (ED) process to remove PPCPs from the effluent to be discharged. A two-compartment ED cell was used testing (i) the effluent position in the cell (anode and cathode compartment); (ii) the use of anion (AEM) and cation exchange membrane (CEM); (iii) the treatment period (6, 12 and 24 hours); (iv) effluent recirculation and current steps; (v) the feasibility of sequential treatments. Phosphorus (P) removal from effluent and energetic costs associated to the process were also evaluated. Five PPCPs were studied – caffeine (CAF), bisphenol A (BPA), 17 β-estradiol (E2), ethinyl estradiol (EE2) and oxybenzone (MBPh). The ED process showed to be effective in the removal when effluent is in the anode compartment. Oxidation is suggested to be the main removal process, which was between 88 and 96%, for all the compounds, in 6 hours. Nevertheless, the presence of intermediates and/or by-products was also observed in some cases. Effluent recirculation should have a retention time in the ED cell big enough to promote removal whereas the current steps (effluent in anode compartment) slightly increased removal efficiencies (higher than 80% for all PPCPs). The sequential set of ED treatment (effluent in anode compartment) showed to be effective during both periods with a removal percentage between 80 and 95% and 73 to 88% in the case of AEM and CEM, respectively. Again, the main removal process is strongly suggested to be oxidation in the anode compartment. However, there was an increase of BOD5 and COD, which might be explained by effluent spiking, these parameters limiting the effluent discharge. From these treatments, the use of AEM, enhanced the P removal from effluent to minimize risk of eutrophication. Energetic costs of the best set-up (6 hours) are approximately 0,8€/m3 of wastewater, a value considered low, attending to the prices of other treatment processes.