792 resultados para 1504
Electrochemical oxidation of wastewater containing aromatic amines using a flow electrolytic reactor
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Aromatic amines are environmental pollutants and represent one of the most important classes of industrial and natural chemicals. Some types of complex effluents containing these chemical species, mainly those originated from chemicals plants are not fully efficiently treated by conventional processes. In this work, the use of electrochemical technology through an electrolytic pilot scale flow reactor is considered for treatment of wastewater of a chemical industry manufacturer of antioxidant and anti-ozonant substances used in rubber. Experimental results showed that was possible to remove between 65% and 95% of apparent colour and chemical oxygen demand removal between 30 and 90% in 60 min of treatment, with energy consumption rate from 26 kWh m-3 to 31 kWh m-3. Absorbance, total organic carbon and toxicity analyses resulted in no formation of toxic by-products. The results suggest that the presented electrochemical process is a suitable method for treating this type of wastewater, mainly when pre-treated by aeration. Copyright © 2013 Inderscience Enterprises Ltd.
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This paper sheds light on the main challenges of teaching Corporate Environmental Management (CEM) in Brazil. Thus, we analysed the main challenges for CEM in Brazil from the viewpoint of teachers. The objective of the research is achieved by means of interviews performed with five renowned professors responsible for teaching CEM in undergraduate courses. Results indicate five types of barriers for teaching CEM: weak integration of other teachers in the teaching of CEM; low level of acceptance of CEM as a subject by the peers teachers; a lack of focus on business while teaching CEM; a scarcity of CEM teaching materials appropriate for the realities of Brazil; and a relative lack of interest among some students in CEM. Teaching CEM is fundamental for the education of more responsible students, but little is known about teaching CEM in Brazil.. Copyright © 2013 Inderscience Enterprises Ltd.
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Incluye Bibliografía
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Incluye Bibliografía
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No ano de 2007, águas superficiais foram coletadas a partir de 21 pontos de amostragem na cidade de Barcarena, Região Norte, Brasil: um ponto de amostragem localizado em um pequeno córrego que recebe descarga de resíduos a partir da indústria de beneficiamento do caulim e deságua no Rio Curuperê, três pontos de amostragens localizados próximos de fontes que emergem na margem esquerda e deságuam no Rio Curuperê, nove pontos de amostragem no Rio Curuperê, que deságua no Rio Dendê, e oito no Rio Dendê, afluente da margem esquerda do Rio Pará. Para todas as amostras de água foram quantificadas 14 variáveis físico-químicas e níveis de 12 metais. Os resultados nos pontos próximos das fontes do Rio Curuperê apresentaram perfil físico-químico e níveis de metais típicos para águas superficiais e esses valores foram utilizados como referência para comparar e identificar possíveis alterações nas características químicas para os demais pontos de amostragem. Quando os resultados das fontes do rio Curuperê foram comparados com os resultados do ponto próximo a descarga de resíduos industriais foram observadas fortes alterações nos valores de 6 variáveis físico-químicas (pH, condutividade elétrica (EC), total de sólidos suspensos (TDS), nitrogênio amoniacal (N-NH4), sulfato (SO4) e salinidade) e aumento em magnitude dos níveis de quatro metais (Al, Fe, Mn e Zn), caracterizando que esses resíduos eram descarregados no ambiente sem tratamentos adequados. Os resultados nos demais pontos de amostragem demonstraram que estas condições anômalas também foram encontradas ao longo dos Rios Curuperê e Dendê, principalmente durante a maré baixa. A partir desta caracterização química das águas foram identificadas condições prejudiciais aos ecossistemas aquáticos e potencial risco à saúde da população local que usa os rios para consumo, recreação e transporte.
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Experimental investigations were carried out using a Nd:YAG laser operating in pulsed mode for welding a lap joint between thin foil and thick sheet. The pulse energy was varied from 1.5 to 3.0 J at increments of 0.25 J with a 4 ms pulse duration. The base material used for this study was AISI 316L foils with 100 mu m thickness and sheet with 3.0 mm thickness. The welds were analysed by optical and electronic microscopy, tensile shear tests and micro hardness. The results indicate that pulse energy control is of considerable importance to join thin foil and thick sheet with good quality. The ultimate tensile strength of the welded joints increased at first and then decreased as the pulse energy increased. The process appeared to be very sensitive to the gap between couples. Large voids delimited by the molten zone boundary were observed in joints welded with high pulse energy.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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O artigo discute o filme de Sérgio Bianchi “Quanto vale ou é por quilo?” Argumenta que a obra é um experimento distópico através do qual o diretor suspende a historicidade e oferece uma interpretação niilista para a desigualdade estruturante da sociedade brasileira. Por meio da construção temporal de mundos paralelos, Bianchi coloca o século XXI em movimento circular com o século XVII, tomado no filme como ponto inicial. Isso gera a percepção não apenas de ausência, mas também de impossibilidade da mudança. Para produzir esse efeito, o diretor opera com a verossimilhança, com o sensacionalismo e com a falácia da parte pelo todo. Esse artigo seleciona algumas cenas e demonstra cada uma dessas operações.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Among all predictive maintenance techniques the oil analysis and vibration analysis are the most important for monitoring some mechanical systems. The integration of these techniques has potential to improve industrial maintenance practices and provide a better economic gain for industries. To study the integration of these two techniques, a test rig was set up to obtain an extreme working condition for the worm reducer used in this paper. The test rig was composed by a motor connected to a reducer through a flexible coupling and with an unbalanced load. The analysis of the results carried out by using a sample of the oil recommended by the manufacturer in extreme conditions, and using liquid contaminant is presented. From the results it was observed that if there is an abnormal instantaneous load in a system, the subsequent vibration analysis may not perceive what occurred if there was no permanent damage, which is not the case with the lubricant analysis.
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The rio Machado (also known as Ji-Paraná) is a tributary of the rio Madeira in the Amazon basin. Currently, the rio Madeira contains the greatest fish species richness of the world, with approximately 1,000 species. The present study presents the fish inventory from streams of the rio Machado basin. In total, 75 stream reaches, 80 meter-length, randomly selected, were sampled in 2011 (August to October) and 2012 (June to July). Overall, 22,875 fish in eight orders, 32 families, 89 genera, and 140 species were collected. Richness estimators indicate that almost 90% of the expected richness was registered. The great majority of specimens (52.2%) was represented by small sized piabas such as Serrapinnus aff. notomelas, Moenkhausia collettii, Serrapinnus microdon, and Hemigrammus melanochrous. Of the total richness, 25 species were restricted to 9°00’ S and 10°00’ S; among them, 14 were exclusive to the lower portion of the basin, which exhibits the larger proportion of native vegetation covering.
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Studies on efficiency achieved greater relevance in organisations within an open market framework, which in Brazil began around 1990. The objective of this paper, applying the data envelopment analysis methodology, is to analyse the efficiency of banks operating in the country using the database termed 'the biggest banks', periodically divulged by the Central Bank of Brazil in 2010-2012. The methodology was applied to the 26 largest banking organisations via two approaches, one was financial intermediation and the other was results. In the financial intermediation approach, the efficiency increase was the highest among banks specialised in credit from 2010 to 2012. Retail banks, especially the large ones, felt most intensely the reaction of 2011, a year considered as the sector's low performance year. In the results approach, the efficiency increase was higher among retail banks. Factors such as retractions in the SELIC rate and bank spreads impacted all banks, regardless of the segment.
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The present study focuses on the presence of covert contrasts in the speech of children with a phonological disorder. The hypothesis is that children with phonological disorders manipulate secondary acoustic cues in an attempt to distinguish the phonological contrasts. We used five audio recordings of the speech of five children with speech disorders, between four and five years of age, who showed the so-called “phonic substitution” involving the sound group of the fricatives. The data were edited and analyzed using the software PRAAT. A phonetic transcription of the first repetition of each child was performed by three evaluators, reaching a 66% agreement level. After the transcription, we carried out a contrastive phonological analysis of the production of the five children and, finally, an acoustic analysis of all the “substitutions”, based on six parameters. We discovered the existence of covert contrasts in the productions auditorily regarded as homophones by the evaluators, representing a total of 54% of total substitutions identified through an impressionistic approach by the evaluators. Children with phonological disorders are seen to rely on secondary acoustic cues in an attempt to distinguish fricative phonemes. The data obtained in this study allow us to reflect on the importance of considering the phonetic detail within the phonological models.
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Syntactic Functionally Graded Metal Matrix Composites (SFGMMC) are a type of composites reinforced by microballoons exhibiting a graded reinforcement distribution. These materials constitute a promising new generation of lightweight structural materials for aerospace, marine and shielding/insulation applications. In this work, A356 alloy reinforced with silica-alumina microballoons (SiO2-Al2O3) was processed by casting techniques. The influence of the microballoon distribution gradient on the corrosion behaviour of the composite was investigated by potentiodynamic polarisation and Electrochemical Impedance Spectroscopy (EIS). Composite surfaces were analysed before and after testing by Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) to determine the influence of microstructural changes.
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The social networks on the internet have experienced rapid growth and joined millions of users in Brazil and throughout the world. Such networks allow groups of people to communicate and exchange information. Sharing information in files is also a growing activity on the internet and is done in various ways. However, applications are not yet available to enable file sharing on Facebook, the premier social network today. This study aims to investigate how users use Facebook, and their practices for file sharing. Due to the experimental nature of this research, we opted for a data collection survey, applied over the web. From the data analysis, we have found a frequent use of file sharing, but no interest in paid services. As for Facebook, there was an extensive use of applications. The set of results shows a favourable scenario for applications that allow file sharing on Facebook.