Desenvolvimento de processo alternativo para a fabricação de materiais cerâmicos envolvendo as técnicas de conformação por consolidação com amido e colagem

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aproveitamento dos resíduos gerados pelo processamento industrial/artesanal de pedra-sabão da região de Ouro Preto

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comparação de critérios de seleção para crescimento em bovinos da raça Nelore

Pós-graduação em Zootecnia - FMVZ

Avaliação da tenacidade à fratura na região de transição dúctil-frágil dos aços API 5L X70 e X80 utilizando a metodologia da curva mestra

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito de diferentes taxas de resfriamento sobre a porcelana feldspática de cobertura para infraestrutura em zircônia

Pós-graduação em Reabilitação Oral - FOAR

Influência do tratamento de superfície na resistência à flexão e na transformação de fase de zircônia tetragonal policristalina estabilizada por óxido de ítrio (y-tzp)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Plataforma regular versus switching: estudo mecânico por meio de testes laboratoriais de fadiga e análise de elementos finitos em implantes com hexágono externo e interno

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação da confiabilidade e modo de falha de coroas cerâmicas parafusadas a implantes osseointegráveis de diferentes conexões

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Determinação de vazões extremas para diversos períodos de retorno para o Rio Paraguai utilizando métodos estatísticos

No presente trabalho foram analisadas as distribuições de probabilidade teórica Normal, Log-Normal, Exponencial, Gama e Weibull, para estimar as vazões máximas e mínimas anuais para o rio Paraguai, utilizando dados de uma estação fluviométrica localizado na cidade de Cáceres-MT. Os testes de Kolmogorov-Smirnov e Qui-Quadrado foram utilizados para verificar a aderência das probabilidades estimadas às freqüências observadas. A série utilizada compreende vazões máximas e mínimas anuais dos anos de 1966 a 2003, excluindo- se dados com falhas. Verificou-se que o melhor ajuste dos valores anuais de vazão máximas e mínimas são referentes a distribuição Gama e Weibull, respectivamente, conforme demonstrado pelo teste de Kolmogorov-Smirnov. Palavras-chave: Previsão de Vazão, teste de aderência.

Avaliação da longevidade de vacas da raça Nelore por diferentes critérios utilizando análise de sobrevivência

Pós-graduação em Genética e Melhoramento Animal - FCAV

Estudo da influência das características químicas e microestruturais nas propriedades mecânicas de sistemas totalmante cerâmicos

Pós-graduação em Odontologia Restauradora - ICT

Quantitative genetic study of age at subsequent rebreeding in Nellore cattle by using survival analysis

The continuous trait age at subsequent rebreeding (ASR) was evaluated using survival analysis in Nellore breed cows that conceived for the first time at approximately 14 months of age. This methodology was chosen because the restricted breeding season produces censored data. The dataset contained 2885 records of ASR (in days). Records of females that did not produce calves in the following year after being exposed to a sire were considered censored (48.3% of the total). The statistical model used was a Weibull mixed survival model, which included fixed effects of contemporary groups (CG) and period and a random effect of individual animal. The effect of contemporary groups on ASR was significant (P < 0.01). Heritabilities obtained for ASR were 0.03 and 0.04 in logarithmic and original scales, respectively. These results indicate that the genetic selection response for subsequent reproduction of 2-year-old Nellore breed females is not expected to be effective based on survival analysis. Furthermore, these results suggest that environmental improvement is fundamental to this important trait. It should be highlighted that an increase in the average date of birth can produce an adverse effect in the future, since this cannot be compensated by genetic improvement.

Mechanical Evaluation of Four Narrow-Diameter Implant Systems

Purpose: This study aimed to evaluate the survival probability of four narrow-diameter implant systems when subjected to fatigue loading. Materials and Methods: Seventy-two narrow-diameter implants to be restored with single-unit crowns were divided into four groups (n = 18): Astra Tech (3.5-mm diameter), with a standard connection (ASC); BioHorizon (3.4-mm diameter), with a standard connection (BSC); Intra-Lock (3.4-mm diameter), with a standard multilobular connection (ISC); and Intra-Lock (3.4-diameter), with a modified square connection (IMC). The corresponding abutments were screwed onto the implants, and standardized metal crowns (maxillary central incisors) were cemented and subjected to step-stress accelerated life testing in water. Use-level probability Weibull curves and reliability for 100,000 cycles at 150 and 200 N (90% two-sided confidence intervals) were calculated. Polarized light and scanning electron microscopes were used to access the failure modes. Results: The calculated survival probability for 100,000 cycles at 150 N was approximately 93% in group ASC, 98% in group BSC, 94% in group ISC, and 99% in group IMC. At 200 N, the survival rate was estimated to be approximately < 0.1% for ASC, 77% for BSC, 34% for ISC, and 93% for IMC. Abutment screw fracture was the main failure mode for all groups. Conclusions: Although the probability of survival was not significantly different among systems at a load of 150 N, a significant decrease was observed at 200 N for all groups except IMC.

Influence of abutment-to-fixture design on reliability and failure mode of all-ceramic crown systems

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

Effect of Abutment Screw Surface Treatment on Reliability of Implant-Supported Crowns

Purpose: To evaluate and compare the reliability of implant-supported single crowns cemented onto abutments retained with coated (C) or noncoated (NC) screws and onto platform-switched abutments with coated screws. Materials and Methods: Fifty-four implants (DT Implant 4-mm Standard Platform, Intra-Lock International) were divided into three groups (n = 18 each) as follows: matching-platform abutments secured with noncoated abutment screws (MNC); matching-platform abutments tightened with coated abutment screws (MC); and switched-platform abutments secured with coated abutment screws (SC). Screws were characterized by scanning electron microscopy and x-ray photoelectron spectroscopy (XPS). The specimens were subjected to step-stress accelerated life testing. Use-level probability Weibull curves and reliability for 100,000 cycles at 200 N and 300 N (90% two-sided confidence intervals) were calculated. Polarized light and scanning electron microscopes were used for fractographic analysis. Results: Scanning electron microscopy revealed differences in surface texture; noncoated screws presented the typical machining grooves texture, whereas coated screws presented a plastically deformed surface layer. XPS revealed the same base components for both screws, with the exception of higher degrees of silicon in the SiO2 form for the coated samples. For 100,000 cycles at 300 N, reliability values were 0.06 (0.01 to 0.16), 0.25 (0.09 to 0.45), and 0.25 (0.08 to 0.45), for MNC, MC, and SC, respectively. The most common failure mechanism for MNC was fracture of the abutment screw, followed by bending, or its fracture, along with fracture of the abutment or implant. Coated abutment screws most commonly fractured along with the abutment, irrespective of abutment type. Conclusion: Reliability was higher for both groups with the coated screw than with the uncoated screw. Failure modes differed between coated and uncoated groups.