A critical evaluation of bond strength tests for the assessment of bonding to Y-TZP

Objectives. To compare three different designs for measuring the bond strength between Y-TZP ceramic and a composite material, before and after ceramic surface treatment, evaluating the influence of the size of the adhesive interface for each design.Methods. 'Macro'tensile, microtensile, 'macro'shear, microshear, 'macro'push-out, and micropush-out tests were carried out. Two Y-TZP surface treatments were evaluated: silanization (sil) and tribochemical silica coating (30 mu m silica-modified Al2O3 particles + silanization) (TBS). Failure mode analysis of tested samples was also performed. Results. Both the surface treatment and the size of the bonded interface significantly affected the results (p = 0.00). Regardless of the type of surface treatment, the microtensile and microshear tests had higher values than their equivalent "macro" tests. However, the push-out test showed the highest values for the "macro" test. The tensile tests showed the greatest variability in results. The tribochemical silica coating method significantly increased bond strength for all tests.Significance. Different test designs can change the outcome for Y-TZP/cement interfaces, in terms of mean values and reliability (variability). The 'micro'tests expressed higher bond strengths than their equivalent 'macro'tests, with the exception of the push-out test (macro > micro). (C) 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Design ergonômico: diretrizes para projetos habitacionais geriátricos

Pós-graduação em Design - FAAC

SNIIC: a plataforma digital de cultura brasileira sob a perspectiva das convergências entre o Design e a Ciência da Informação

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Chromic oxide as a digestibility marker for dogs - A comparison of methods of analysis

The study reported compared coefficients of apparent digestibility (CAD) obtained by total collection (TC) and by chromic oxide (Cr2O3) determined by visible absorption spectrometry (VIS) and flame atomic absorption spectrophotometry (FAAS). These quantification methods were also investigated to assess their precision. Nineteen adult dogs housed in individual digestibility cages were fed three commercial diets, each test including five or seven animals. The experiment was carried out in a completely randomized design with three among-subjects factors (foods) and three within-subject factors (methods), and the dogs were the experimental unit. Estimated CAD for all dietary components in the three diets by either chromium quantification methods did not differ and showed fair agreement with TC results (P > 0.05). Coefficients of chromic oxide recoveries in feces were 1.06 +/- 0.044 and 1.01 +/- 0.045 for VIS and FAAS, respectively, values significantly different (P < 0.05), indicating better recovery for FAAS. Significant differences (P<0.05) were found in the mean concentration of Cr2O3 for diets and feces (17 +/- 0.6 and 19 +/- 0.8g/kg for VIS and FAAS, respectively). Coefficient of variation for FAAS was 1.69% and 1.77% for VIS, which did not differ significantly (P > 0.05). Pearson's correlation coefficient (r=0.99; P < 0.01) indicated positive and significant association among the results for VIS and FASS, indicating reasonable precision and agreement of chromic oxide contents determined by these methods. Therefore, FAAS and VIS can be used successfully to determine Cr2O3 in dog foods and feces. (c) 2006 Elsevier B.V. All rights reserved.

Performance of layers submitted to different forced-molting methods and different temperatures

This study was carried out to evaluate the performance and egg quality of laying hens, in their second laying cycle submitted to different forced-molting methods and three environmental temperatures. Six hundred layers were distributed in a completely randomized experimental design with 15 treatments with five replicates of eight birds each, according to 5x3 factorial arrangement (molting methods vs. temperatures). The following forced-molting methods were applied: 90%, 70%, 50% dietary alfalfa inclusion, addition of 2,800 ppm zinc, and feed fasting. Temperatures were: 20 ºC, 27 ºC and 35 ºC. At the end of each period of the second laying cycle, bird performance and egg quality were evaluated. Data were submitted to analysis of variance and means were compared by orthogonal and polynomial contrasts. The highest alfalfa inclusion level (90% alfalfa and 10% basal diet) proved to be efficient as compared to the other methods, independently of temperature.

On relaxed LMI-based design for fuzzy controllers

Relaxed conditions for stability of nonlinear continuous-time systems given by fuzzy models axe presented. A theoretical analysis shows that the proposed method provides better or at least the same results of the methods presented in the literature. Digital simulations exemplify this fact. This result is also used for fuzzy regulators design. The nonlinear systems are represented by fuzzy models proposed by Takagi and Sugeno. The stability analysis and the design of controllers axe described by LMIs (Linear Matrix Inequalities), that can be solved efficiently using convex programming techniques.

Ultrasonic density measurement cell design and simulation of non-ideal effects

This paper presents a theoretical analysis of a density measurement cell using an unidimensional model composed by acoustic and electroacoustic transmission lines in order to simulate non-ideal effects. The model is implemented using matrix operations, and is used to design the cell considering its geometry, materials used in sensor assembly, range of liquid sample properties and signal analysis techniques. The sensor performance in non-ideal conditions is studied, considering the thicknesses of adhesive and metallization layers, and the effect of residue of liquid sample which can impregnate on the sample chamber surfaces. These layers are taken into account in the model, and their effects are compensated to reduce the error on density measurement. The results show the contribution of residue layer thickness to density error and its behavior when two signal analysis methods are used. (c) 2006 Elsevier B.V. All rights reserved.

Optimal design of smart structures using bonded plezoelectrics for vibration control

Smart material technology has become an area of increasing interest for the development of lighter and stronger structures which are able to incorporate actuator and sensor capabilities for collocated control. In the design of actively controlled structures, the determination of the actuator locations and the controller gains, is a very important issue. For that purpose, smart material modelling, modal analysis methods, control and optimization techniques are the most important ingredients to be taken into account. The optimization problem to be solved in this context presents two interdependent aspects. The first one is related to the discrete optimal actuator location selection problem which is solved in this paper using genetic algorithms. The second is represented by a continuous variable optimization problem, through which the control gains are determined using classical techniques. A cantilever Euler-Bernoulli beam is used to illustrate the presented methodology.

Comparison of the univariate and multivariate methods in the optimization of experimental conditions for determining Cu, Pb, Ni and Cd in biodiesel by GFAAS

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

Beak trimming methods and their effect on the performance and egg quality of Japanese quails (Coturnix japonica) during lay

A total number of 720 Japanese quail females, reared under identical management conditions, and receiving feed and water ad libitum, was used. Quails were housed and reared from 1-35 days of age in litter pens in a rearing house, and then were transferred to a quail layer house. This study aimed at verifying if different beak trimming method could optimize egg production and quality by reducing stress and cannibalism among birds. A completely randomized experimental design was used, with six treatments in a 2x3 factorial arrangement, with two beak trimming ages (14 and 21 days) and three beak trimming variants (non-trimmed, 1/3 of the beak trimmed, or 1/2 of the beak trimmed), 6 replicates of 20 birds each. Performance was evaluated by feed intake, percentage of lay, egg mass, feed conversion ratio per dozen and per kg eggs, and mortality. Performance was influenced by trimming variant, with the best results obtained by birds with intact and those with 1/3 of the beak trimmed. Better specific gravity was in quails submitted to beak trimming at 21 days of age, whereas other egg quality parameters did not present significant results. Based the results obtained in the present study, it is recommended to submit to beak trimming either at 14 or 21 days of age.

Beak-trimming methods and their effect on the performance of japanese quail pullets (Coturnix japonica)

This study aimed at verifying if beak-trimming methods in Japanese quail pullets could optimize production by decreasing stress caused by cannibalism. A total number of 816 day-old Japanese quails was distributed in a completely randomized experimental design in a 2 x 3 factorial arrangement, with two beak-trimming ages (14 and 21 days of age) and three beak-trimming sizes (not trimmed, 1/3 trimmed, or 1/2 trimmed), and 4 replicates of 34 birds per replicate. Birds were submitted to the same management and feeding conditions. Weight gain, feed intake, feed conversion ratio, and mortality were evaluated. There was no significant effect of age at beak trimming on the evaluated parameters (P>0.05), as well as no significant interaction between age at beak trimming, and beak-trimming method. There was a significant effect (P<0.01) of trimming size on performance, with the best performance observed in birds not submitted to beak trimming or had 1/2 of the beak trimmed. When the beak was more aggressively trimmed (1/2), parameters were worse. According to the obtained results, it is recommended to trim 1/3 of the beaks, which can be performed either at 14 or 21 days of age.

Forced-Molting methods and their effects on the performance and egg quality of japanese quails (Coturnix japonica) in the second laying cycle

The experiment was carried out in the experimental poultry house of the Research and Development Unit of Brotas of Agência Paulista de Tecnologia dos Agronegócios do Centro-Oeste, SP, Brazil. The objective of the study was to evaluate the performance of Japanese quails submitted to forced molting aiming at optimizing the use of the same quail flock by promoting a second laying cycle. A total number of 400 67-day-old Japanese quails in lay, previously submitted to 14 days of forced molting, was distributed in a completely randomized experimental design into five treatments (T1= not submitted to forced molting, T2= 03 days of fasting + fed ad libitum, T3= 01 days of fasting + 13 days of feed restriction, T4= 02 days of fasting + 12 days of feed restriction, and T5= 03 days of fasting + 11 days of feed restriction. Feeds were contained equal nutrient levels, and were formulated according to NRC (1994) recommendations. There were significant differences among the studied treatments. Although the treatment of 3 days of fasting followed by ad libitum feeding resulted in lower egg weight, it promoted better lay percentage, egg mass, and feed conversion ratios (FCR/dz and FCR/kg). on the other hand, 3 days of fasting followed by restricted feeding resulted in higher feed intake and worse feed conversion ratios (FCR/dz and FCR/kg). When birds were not submitted to forced molting, they presented lower lay percentage and egg mass.

The effects of alternative forced-molting methods on the performance and egg quality of commercial layers

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

Influence of the Connector and Implant Design on the Implant-Tooth-Connected Prostheses

Purpose:The purpose of this study was to evaluate stress transfer patterns between implant-tooth-connected prostheses comparing rigid and semirigid connectors and internal and external hexagon implants.Materials and Methods:Two models were made of photoelastic resin PL-2, with an internal hexagon implant of 4.00 x 13 mm and another with an external hexagon implant of 4.00 x 13 mm. Three denture designs were fabricated for each implant model, incorporating one type of connection in each one to connect implants and teeth: 1) welded rigid connection; 2) semirigid connection; and 3) rigid connection with occlusal screw. The models were placed in the polariscope, and 100-N axial forces were applied on fixed points on the occlusal surface of the dentures.Results:There was a trend toward less intensity in the stresses on the semirigid connection and solid rigid connection in the model with the external hexagon; among the three types of connections in the model with the internal hexagon implant, the semirigid connection was the most unfavorable one; in the tooth-implant association, it is preferable to use the external hexagon implant.Conclusions:The internal hexagon implant establishes a greater depth of hexagon retention and an increase in the level of denture stability in comparison with the implant with the external hexagon. However, this greater stability of the internal hexagon generated greater stresses in the abutment structures. Therefore, when this association is necessary, it is preferable to use the external hexagon implant.

Artificial methods of dentine caries induction: A hardness and morphological comparative study

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)