Fotocatálise heterogênea em instrumental odontológico recoberto com nanopartículas TiO2 e Ag

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Inativação de bactérias em fase gasosa por fotocatálise heterogênea: efeito da adição de metais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo da deformação heterogênea no ensaio do anel de atrito

The plastic deformation is widely used in the metallurgical market due to its positive factors such as low prices and high speed production. Forming process products are obtained in high quality, both surface quality and mechanical properties. Friction is an importante factor in metal forming. Friction study in metal forming can be accomplished indirectly, such as the ring test of friction. Two samples of different materials being mild steel and copper alloy were used. The results showed the influence of friction in the flow behavior of the deformation of the second phase, as evidenced by standard metallography. It is observed that in the outer regions of the ring, plastic deformation occured in the radial direction. In the central region of the disc deformation occured in the direction of compression and the inner region of the ring flux lines showed a significant deformation in the radial direction towards the center of the ring

Reflexõs sobre a linguagem do ambiente chat no Teletandem sob a perspectiva da natureza heterogênea da escrita

This paper aims at discussing the characteristics of computer mediated language within a foreign language teaching and learning environment enabled by the use of synchronic writing resources – chat. The present research is based on (i) theoretical principles about the use of technologies and the teaching-learning of foreign languages in the scope of the Teletandem Brazil Project: Foreign languages for all – Projeto Teletandem Brasil: línguas estrangeiras para todos (TELLES, 2005); (ii) studies on the characteristics of the language within chat interactions; (iii) different theoretical perspectives on the relationship between spoken and written language, emphasizing the constitutive heterogeneity of writing perspective (CORRÊA, 1997, 1998, 2001); and (iv) some relevant concepts related to Prosodic Phonology field (NESPOR; VOGEL, 1986). Is being taken as research data, the written production of a Brazilian student (finishing a Licentiate in Literature) interacting with an American student (in Religious Studies) through Windows Live Messenger. The data were collected during a five-month period, during which the participants interacted through chat, totalizing 12 interactions in English and in Portuguese. During the analysis, a particular attention was given to the messages’ fragmentation, the use (or not) of punctuation signs and abbreviations within the Brazilian participant’s production, in order to discuss the representations she built of her writing, her interlocutor, herself and on the teaching-learning process of a foreign language.

Fotocatálise heterogênea de enterococcus faecalis e pseudomonas aeruginosa desencadeada pela ação da luz UV e branca em espátulas com revestimento de nanopartículas TiO2 e Ag

Nanotechnology, the science of minuscule, has developed products which are able t o manipulate atoms and molecules that could be applied in the sterilization process of dental instruments. Objetives: The objective of the present study was to evaluate the self-cleaning action of TiO2 and Ag nanoparticles coating on dental instruments by the photocataliys process under UV and visible light irradiation. Material and method: Microbiologic tests were done using dental cement spatulas coated with TiO2 and Ag nanoparticles (one or three layers), and contaminated with 10 mcrl of Pseudomonas aeruginosa and Enterococcus faecalis, respectively. After contamination, they were exposed to ultraviolet light and visible light for 120 minutes. Next, they were transferred to and stored in test tubes with BHI (Brain Heart Infusion) and incubated in 35 to 37 °C. Checking times for bacterial growth and for control and retrieval tests were done at: 24, 48, 72 and 96 hours. Result: The Pseudomonas aeruginosa was inactive after 120 minutes of ultraviolet light irradiation, thus confirming the heterogeneous photocatalytic activity of TiO2 and Ag. The Pseudomonas aeruginosa was not inactivated under visible light irradiation and the Enterococcus faecalis was not inactivated under UV and visible light irradiation of the dental cement spatulas coated with TiO2 and Ag nanoparticles in the readings to 96 hours, showing bacterial growth. Conclusion: There were no influence of one or three layers of TiO2 and Ag nanoparticles coating of the spatulas in the results. The heterogeneous photocatalysis activity of TiO2 and Ag under UV light irradiation was confirmed for Pseudomonas aeruginosa but not under visible light. Enterococcus faecalis did not confirmed the photocatalytics activity of TiO2 and Ag under UV light irradiation and visible lights irradiation.

Aluminas macro-mesoporosas produzidas pelo método sol-gel para aplicação em catálise heterogênea

Pós-graduação em Química - IQ