Aplicação de cavacos de titânio para produção de revestimentos resistentes ao desgaste

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo comparativo do desgaste de ferramentas cerâmicas de Al2O3 em relação às de B4C + TiB2

Due to the high value of the bill that the Brazilian has been paying, one of the most expensive in the world, is becoming increasingly attractive the option for renewable energy in form of distributed micro and minigeneration. In other words, the renewable energy sources are becoming attractive not only because of environmental concerns, but also due to economic issues. This has become even more relevant and concrete after approval of rules by National Agency of Electric Energy (ANEEL) on 4/17/2012 (Normative Resolution n ° 482/2012 of 04/17/2012) aimed at reducing barriers to installation of small distributed generation, including microgeneration, with up to 100 kW of power, and minigeneration, 100 kW to 1 MW. The Normative Resolution n ° 482/2012 creates the Energy Clearing System, which allows consumers to install small generators in its consumer unit and exchange energy with the local distributor. The rule applies to generators that use renewable sources of energy (hydro, solar, biomass, wind and cogeneration qualified). In this context, this paper presents a technical and economic analysis of installing a residential microgenerating plant composed of photovoltaic cells, solar panels and small wind turbines

Análise do comportamento do desgaste de dressadores de ponta única confeccionados com diamantes naturais e sintético piramidais

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Analise de desgaste em materiais aplicados em discos de freio

Baja SAE competitions challenge engineering students to design and build offroad vehicles, preparing them for the competitive job market. This monograph aims to study a part of the braking of a Baja SAE vehicle system, the brake disc. Giving attention to the wear suffered by discs of two different materials, steel 1045 and stainless steel 304, helping the team Piratas do Vale Bardahl in the best selection between them. Braking tests were performed on a test bench. Both discs have suffered the same braking conditions. Brake pads material, brake line pressure, braking time, number of braking, were parameters which were repeated in the testing of different types of disk, in order to ensure a high power comparison between the obtained data. Before and after the disk tests were weighed and measured, to make a comparison. After the brake tests, the disks were subjected to hardness and surface roughness testing. With the data collected and observations made in the worn parts, the comparison between these two materials was made, obtaining a selection of the best material for the team. The tests showed that steel 1045 has more advantages, compared to stainless steel 304, when applied to brake discs, on the tested conditions

Efeito da escovação utilizando dentifrícios com diferentes graus de abrasividade no desgaste do esmalte após o uso de agentes clareadores com e sem cálcio, em diferentes intervalos de tempo

Pós-graduação em Odontologia Restauradora - ICT

Construção de um equipamento de ensaio de desgaste micro abrasivo por esfera rotativa fixa para análise do desgaste em revestimento duro aplicado por soldagem

Pós-graduação em Engenharia Mecânica - FEIS

Desgaste superficial do esmalte dental após microabrasão in vitro

The aim of this study was to investigate the enamel wear permanent teeth after plastic stick or low speed rubber cup microabrasion. Ten permanent molars were selected to evaluate enamel wear which were sectioned into mesial and distal halves. Each half of the molars was randomly assigned to one of two experimental groups (n = 10) according to the enamel microabrasion technique: plastic stick (GE) or rubber cup (GT). In both the groups, the enamel was submitted to 10 applications of an abrasive paste comprised of 35% phosphoric acid and pumice powder. The paste was applied for 20 seconds under a pressure of 30 g using the instrument defined for each group (plastic stick or rubber cup). The specimens were evaluated under a stereomicroscope connected to a computer. The enamel wear no was statistically different between GE and GT, which presented a mean wear of 304.74 µm (21.20%) and 338.35 µm (22.75%). In conclusion, superficial enamel wear was seen for both the groups, independent of the technique used for the accomplishment of the microabrasion.

Desgaste e rugosidade superficial de um cimento de ionômero de vidro nanoparticulado

To compare the abrasion wear resistance and superficial roughness of different glass ionomer cements used as restorative materials, focusing on a new nanoparticulate material. Material and Method: Three glass ionomer cements were evaluated: Ketac Molar, Ketac N100 and Vitremer (3M ESPE, St. Paul, MN, USA), as well as the Filtek Z350 (3M ESPE, St. Paul, MN, USA). For each material were fabricated circular specimens (n=12), respecting the handling mode specified by the manufacturer, which were polished with sandpaper disks of decreasing grit. The wear was determined by the amount of mass (M) lost after brushing (10,000 cycles) and the roughness (Ra) using a surface roughness tester. The difference between the Minitial and Mfinal (ΔM) as well as beroughness of aesthetic restorative materials: an in vitro comparison. SADJ. 2001; 56(7): 316-20. 11. Yip HK, Peng D, Smales RJ. Effects of APF gel on the physical structure of compomers and glass ionomer cements. Oper. Dent. 2001; 26(3): 231-8. 12. Ma T, Johnson GH, Gordon GE. Effects of chemical disinfectants on the surface characteristics and color of denture resins. J Prosthet Dent 1997; 77(2): 197-204. 13. International organization for standardization. Technical specification 14569-1. Dental Materials – guidance on testing of wear resistance – PART I: wear by tooth brushing. Switzerland: ISO; 1999. 14. Bollen CML, Lambrechts P, Quirynen M. Comparison of surface roughness of oral hard materials to the threshold surface roughness for bacterial plaque retention: a review of the literature. Dent Mater.1997; 13(4): 258-9. 15. Kielbassa AM, Gillmann C, Zantner H, Meyer-Lueckel H, Hellwig E, Schulte-Mönting J. Profilometric and microradiographic studies on the effects of toothpaste and acidic gel abrasivity on sound and demineralized bovine dental enamel. Caries Res. 2005; 39(5): 380-6. 16. Tanoue N, Matsumara H, Atsuta M. Wear and surface roughness of current prosthetic composites after toothbrush/dentifrice abrasion. J Prosthet Dent. 2000; 84(1): 93-7. 17. Heath JR, Wilson HJ. Abrasion of restorative materials by toothpaste. J Oral Rehabil. 1976; 3(2): 121-38. 18. Frazier KB, Rueggeberg FA, Mettenburg DJ. Comparasion of wearresistance of class V restorative materials. J Esthet Dent. 1998; 10(6): 309-14. 19. Momoi Y, Hirosakil K, Kohmol A, McCabe JF. In vitro toothebrushdentifrrice abrasion of resin-modified glass ionomers. Dent Mater. 1997; 13(2): 82-8. 20. Turssi CP, Magalhães CS, Serra MC, Rodrigues Jr.AL. Surface roughness assessment of resin-based materials during brushing preceded by pHcycling simulations. Oper Dent. 2001; 26(6): 576-84. 21. Wang L, Cefaly DF, Dos Santos JL, Dos Santos JR, Lauris JR, Mondelli RF, et al. In vitro interactions between lactic acid solution and art glassionomer cements. J Appl Oral Sci. 2009; 17(4): 274-9. 22. Carvalho FG, Fucio SB, Paula AB, Correr GM, Sinhoreti MA, PuppinRontani RM. Child toothbrush abrasion effect on ionomeric materials. J Dent Child (Chic). 2008; 75(2): 112-6. 23. Coutinho E, Cardoso MV, De Munck J, Neves AA, Van Landuyt KL, Poitevin A, et al. Bonding effectiveness and interfacial characterization of a nano-filled resin-modified glass-ionomer. Dent Mater. 2009; 25(11): 1347-57. tween Rainitial and Rafinal (ΔRa) were also used for statistical analysis (α=0.05). Results: Except for the composite, significant loss of mass was observed for all glass ionomer cements and the ΔM was comparable for all of them. Significant increase in roughness was observed only for Vitremer and Ketac N100. At the end of the brushing cycle, just Vitremer presented surface roughness greater than the composite resin. Conclusion: All glass ionomer cements showed significant weight loss after 10,000 cycles of brushing. However, only Vitremer showed an increase of roughness greater than the Z350 resin, while the nanoparticulate cement Ketac N100 showed a smooth surface comparable to the composite.

Efeito de métodos de desgaste com pontas diamantadas e da ressinterização sobre o limite de fadiga flexural de uma zircônia parcialmente estabilizada por ítria

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Contribuição ao estudo do desgaste de bedames na usinagem de ligas de alumínio-silício

Pós-graduação em Engenharia Mecânica - FEIS

Saúde bucal e educação infantil: avaliação do desgaste e do acondicionamento de escovas dentárias utilizadas por pré-escolares

Introduction: Early childhood is an essential phase of life for the future of oral health. The link between educational and health sectors can facilitate incorporating educational and preventive oral health practices in daily teaching in pre-schools. The main measure is manual tooth-brushing, which is the most accessible method for most of the population. Objective: The objective of this study is to evaluate macroscopically the wear on the bristles, form of storage, and identification of tooth brushes. Material and method: 345 toothbrushes used by children between the ages of 2 and 5 were evaluated in 4 pre-schools, by 2 participants from the oral health program. The Rawls et al. index was used to evaluate the bristles. Result: There were statistically significant differences (p = 0.020 - Mann-Whitney U test) between the frequency of toothbrushes, with the highest being (n = 205) stored at participating school; and, between adequate and inadequate brushes (p < 0.05 - X2 test) with 31.7 and 60%, respectively, classified as unfit for tooth-brushing. Of the toothbrush holders evaluated 100% were used collectively. Regarding identification, 18% of the toothbrushes were not identified in participating schools, and 37% in the others. Conclusion: The toothbrushes exhibited marked wear, and storage was inadequate; however, the schools participating in the oral health program showed toothbrushes with bristles less worn. It is suggested that training of educators regarding correct storage and evaluation of toothbrushes for wear of the bristles should be undertaken in all early childhood schools.

Desgaste e encruamento nos aços Hadfield

O aço austenítico manganês, descoberto inicialmente por Robert Hadfield, em 1882, conhecido atualmente como aço Hadfield, continha em sua configuração inicial 12% de manganês e 1,2% de carbono. Apresentando grande resistência ao desgaste, provavelmente o maior na categoria de aciaria, ganhou rápida aceitação no mercado, sendo então propostas várias alterações em sua composição, como a introdução de vários elementos de liga, como o vanádio, molibdênio, titânio, enxofre, fósforo, cromo, níquel, entre outros. Este trabalho investigou a influência dos elementos de liga na resistência ao desgaste e no encruamento sofrido por esse material, em quatro composições que se diferenciam nos elementos de liga e em suas porcentagens. A resposta foi uma grande resistência ao desgaste da liga contendo titânio, entretanto esta não apresentou a maior profundidade de camada encruada.

Avaliação do desgaste de diamantes sintéticos na dressagem (afiação) de rebolos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparação de desgaste para dois tipos diferentes de diamantes sintéticos CVD em sua utilização para a dressagem de ponta única de rebolos de óxido de alumínio

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Análise do desgaste em ferramentas de diamantes nacionais

Três tipos de diamantes foram observados neste trabalho, para determinar qual apresenta a melhor relação entre desgaste e tempo de vida de um dressador de ponta única. A metodologia empregou o dressamento de um rebolo de óxido de alumíno e, a cada vinte passes, com avanço da profundidade de dressagem de 40 μm por passe, registrou uma imagem da ponta da ferramenta em um estereoscópio. O dressador foi então recolocado na retificadora para a realização de novas dressagens até o fim de vida do diamante. O critério para o fim do ensaio foi o faiscamento gerado pelo contato do rebolo com a base do dressador. Foram realizados três ensaios para cada tipo de diamante. O Mato Grosso apresentou os maiores desgastes de área, e o Brasil Extra, o menor. O CVD nacional teve desempenho parecido com o do Brasil Extra, mas com tempo maior de dressagem nos ensaios. Ou seja, apresentou baixo desgaste e durabilidade maior.