Ti-Mo alloys employed as biomaterials: Effects of composition and aging heat treatment on microstructure and mechanical behavior

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

Mechanical and Thermal Properties of Thermoplastic Random Copolyesters Made from Lipid- Derived Medium and Long Chain Poly (x-hydroxyfatty acid) s

The physical properties of novel thermoplastic random copolyesters [-(CH2)(n)-COO-/-(CH2)(n)-COO-](x) made of long (n=12) and medium (n=8) chain length -hydroxyfatty esters [HO-(CH2)(n)-COOCH3] derived from bio-based vegetable oil feedstock are described. Poly(-hydroxy tridecanoate/-hydroxy nonanoate) P(-Me13-/-Me9-) random copolyesters (M-n=11,000-18,500 g/mol) with varying molar ratios were examined by TGA, DSC, DMA and tensile analysis, and WAXD. For the whole range of P(-Me13-/-Me9-) compositions, the WAXD data indicated an orthorhombic polyethylene-like crystal packing. Their melting characteristics, determined by DSC, varied with composition suggesting an isomorphic cocrystallization behavior. TGA of the P(-Me13-/-Me9-)s indicated improved thermal stability determined by their molar compositions. The glass transition temperature, investigated by DMA, was also found to vary with composition. The crystallinities of P(-Me13-/-Me9-)s however, were unaffected by the composition. The stiffness (Young's modulus) of these materials was found to be related to their degrees of crystallinity. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40492.

Influence of Oxygen Content and Microstructure on the Mechanical Properties and Biocompatibility of Ti-15 wt%Mo Alloy Used for Biomedical Applications

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of the surface treatment of tire rubber residues added in mortars

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

Effect of Ceramic Thickness and Shade on Mechanical Properties of a Resin Luting Agent

Purpose: This study aimed to investigate the influence of ceramic thickness and shade on the Knoop hardness and dynamic elastic modulus of a dual-cured resin cement.Materials and Methods: Six ceramic shades (Bleaching, A1, A2, A3, A3.5, B3) and two ceramic thicknesses (1 mm, 3 mm) were evaluated. Disk specimens (diameter: 7 mm; thickness: 2 mm) of the resin cement were light cured under a ceramic block. Light-cured specimens without the ceramic block at distances of 1 and 3mm were also produced. The Knoop hardness number (KHN), density, and dynamic Young's moduli were determined. Statistical analysis was conducted using ANOVA and a Tukey B rank order test (p = 0.05).Results: The bleaching 1-mm-thick group exhibited significantly higher dynamic Young's modulus. Lower dynamic Young's moduli were observed for the 3-mm-thick ceramic groups compared to bleaching 3-mm-thick group, and no difference was found among the other 3-mm groups. For the KHN, when A3.5 3-mm-thick was used, the KHN was significantly lower than bleaching and A1 1-mm-thick ceramic; however, no difference was exhibited between the thicknesses of the same shade.Conclusions: The dual-cured resin cement studied irradiated through the 1-mm-thick ceramic with the lightest shade (bleaching ceramic) exhibited a better elastic modulus, and there was no effect in KHN of the resin cement when light cured under different ceramic shades and thicknesses (1 and 3 mm), except when the A3.5 3-mm-thick ceramic was used.Clinical Significance: Variolink II irradiated through ceramic with the lowest chroma exhibited the highest elastic modulus; therefore, the light activation method might not be the same for all clinical situations.

O gênero em questão: crítica e formação nos Bildungsromane The Secret Life of Bees, de Sue Monk Kidd, e Sapato de salto, de Lygia Bojunga

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

Lifetime comparison of Y-TZP/porcelain crowns under different loading conditions

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influence of CAD-CAM diamond bur deterioration on surface roughness and maximum failure load of Y-TZP-based restorations

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

Study of thermocycling effect on the bond strength between an aluminous ceramic and a resin cement

This study evaluated the effect of thermocycling on the bond strength between Procera AllCeram (Nobel-Biocare) and a resin cement (Panavia F, Kuraray CO). Nine ceramic blocks with dimensions of 5x6x6mm were conditioned at one face with Rocatec System (Espe). After, they were luted with Panavia F to composite resin blocks (Clearfil AP-X, Kuraray CO). The nine groups formed by ceramic, cement and composite resin were split up obtaining 75 samples with dimensions of 12x1x1mm and adhesive surface presenting 1mm2±0.1mm2 of area. The samples were divided into 3 groups (n=25): G1 - 14 days in distilled water at 37ºC; G2 – 6,000 cycles in water (5ºC - 55ºC – 30s); G3 – 12,000 cycles in water (5ºC - 55ºC – 30s). The samples were tested in a universal testing machine (EMIC) at a crosshead speed of 1mm/min. Data were analyzed by ANOVA and Tukey tests. The results indicated that mean values of rupture tension (MPa) of G1 (10.71 ± 3.54) did not differ statistically (p <5%) from G2 (9.01 ± 3.90), however there was statistical difference between G1 and G3 (7.28 ± 3.00). It was concluded that thermocycling significantly reduced the bond strength values when samples were submitted to 12,000 cycles.

Inflation in supergravity and the volume modulus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito da vinhaça na membrana impermeabilizante usada nos tanques de armazenamento

This work evaluated the effect of vinasse (residue from sugar cane) in high density polyethylene (HDPE) geomembranes having in mind that it is deposited at temperatures of 80-90˚C on the geomembrane in storage tanks. The objective was to evaluate the resistance of the geomembrane in contact with residue in a total period of 4 months. Physical and mechanical tests, and thermogravimetric analysis (TGA) were used to determine degradation of polymer membranes after chemical immersion. In general, the results obtained show that the vinasse affected the geomembranes significantly in some aspects, for instance, the thickness of the material presented a variation of 7.8%. The average values in both directions at yielding showed a significant loss of tensile strength (34.13%) and strain (23.48%) and an increase in the modulus of elasticity (9.63%). At the rupture the behavior presented the same trend: a loss of 32% for tensile strength and 24.4% for the deformation were observed. Tear strength presented small decrease (4.72%) and puncture resistance a increase of 7.9% after immersion of geomembranes. The TGA tests were not efficient to detect evidence of degradation in samples of geomembranes after exposures, but identified problems in the quality of the supplied material.

Influence of storage period of pieces in stiffness of pinus elliottii Glulam Beams

This study aimed to investigate the influence of storage time (0, 48 hours) of Pinus elliottii pieces and the tests to obtaining modulus of elasticity (static bending and transversal vibration) in glued laminated timber beams, produced with resorcinol based adhesive and 0.8 MPa compaction pressure. After pieces were properly prepared, part of them was used in immediate three manufacturing glulam beams, tested after adhesive cure, and part stored for 48 hours under a roof with a temperature of 25°C and relative humidity of 60% for subsequent manufacturing and testing three other glulam beams. Results of analysis of variance (ANOVA) revealed that the storage period was significant influence in modulus of elasticity obtained in static bending test (8% reduction from 0 to 48 hours). This not occurred with modulus of elasticity obtained by transversal vibration test (no significant influence). ANOVA results showed equivalence of means in both test procedures. New researches ire needed to better understand the investigated phenomenon, using new wood species, other storage conditions and a great number of samples.

Influence of the number of load cycles to obtain the stiffness properties of angico preto (Anadenanthera macrocarpa) wood specie

The tests used to obtain the stiffness properties of wood are made with two loading cycles, as defined by the Brazilian standard ABNT NBR 7190 (Design of Timber Structures). However, the possibility of reducing the number of cycles allows decrease the operating time of the machine, resulting in reduced spending on electricity used during the tests. This research aimed to investigate, with the aid of the analysis of variance (ANOVA), the influence of the use of three load cycles to obtain the modulus of elasticity in compression parallel to grain (Ec0), in tensile parallel to the grain (Et0), in bending (Em) and in compression perpendicular to the grain (Ec90) of Angico Preto (Anadenanthera macrocarpa) wood specie. For the number of cycles and stiffness were manufactured 12 samples, totaling 144 specimens. The results of the ANOVA revealed statistical equivalence between the stiffness properties for both load cycle numbers evaluated, indicating that it is possible to carry out the tests with a single charge cycle, allowing savings in time and energy in the operation of the equipment.

Determinação do módulo de elasticidade da madeira juvenil e adulta de Pinus taeda por ultra-som

A madeira de Pinus sp. tem utilização crescente na indústria madeireira brasileira. O decréscimo constante do suprimento de árvores adultas com grandes diâmetros, provenientes de florestas naturais, tornou comum a produção de madeira em ciclos curtos, com grande proporção de madeira juvenil. Resultados de diversas pesquisas têm reportado que o módulo de elasticidade e a resistência a diferentes solicitações mecânicas são seriamente afetados pela presença de madeira juvenil. Este trabalho teve por objetivo determinar o módulo de elasticidade da madeira juvenil e adulta de Pinus taeda L. a partir da constante dinâmica C LL, obtida em ensaios não-destrutivos de ultra-som. A madeira de P. taeda era originária de plantios da Estação Experimental de Itapeva - SP, sendo amostrados seis indivíduos arbóreos com 34 anos de idade. Os corpos-de-prova (4 cm x 4 cm x 45 cm) foram obtidos separadamente das regiões de madeira juvenil e adulta da prancha central, previamente submetida à secagem industrial (umidade final de 12%), para a determinação da constante dinâmica por meio de ensaios de ultra-som. Para avaliar a sensibilidade do método do ultra-som, os corpos-de-prova foram ensaiados destrutivamente à compressão paralela. Os resultados mostraram boa sensibilidade do método do ultra-som (R² » 0,90) na avaliação desse parâmetro mecânico da madeira juvenil e adulta.

Efeito tardio e imediato da sutura em tendão extrassinovial íntegro: estudo biomecânico em ratos

OBJETIVO: O objetivo do estudo foi avaliar o efeito, nas propriedades mecânicas, do arranjo de reparo com material de sutura, no tendão calcâneo de rato, na ausência de processo de cicatrização. MÉTODO: Foram utilizados 12 ratos machos da linhagem Wistar. Os animais foram submetidos à colocação de ponto de sutura tipo Kessler modificado no tendão calcâneo. Os sacrifícios foram realizados nos períodos imediato e com seis semanas de pós-operatório. As propriedades mecânicas estudadas foram: carga máxima, tensão na carga máxima e módulo de elasticidade. O tendão contralateral foi usado como controle. RESULTADOS: A análise estatística indicou que, em relação aos períodos estudados, os valores das propriedades mecânicas não apresentaram diferenças significativas. em relação ao controle, isto é, tendão contralateral sem sutura, os resultados demonstram que, com seis semanas de pós-operatório, houve queda dos valores do módulo de elasticidade, enquanto a carga máxima e a tensão na carga máxima não apresentaram variações significativas. CONCLUSÃO: A colocação de material de sutura em tendão extrassinovial não lesado provocou queda do módulo de elasticidade, porém não interferiu na carga máxima e na tensão na carga máxima após seis semanas de pós-operatório.