Brazilian scientific production in science education

In the present study we analyzed the Brazilian scientific production in the area of science education. The study was structured on: data by research groups registered in Conselho Nacional de Desenvolvimento Científico e Tecnológico; analysis of the post-graduate strictu sensu programs; analysis of theses and dissertations linked to post-graduate programs; and papers in international databases. Our research was conducted strictly via world wide web, from December 2009 to September 2010. It was found that both number of research groups, researchers, post-graduate programs, thesis, dissertations and papers presented a marked increase, especially in the last decade (from 2000 onwards). The major research centers were found to be located in public universities from Brazilian southeast and south regions. However, it was observed a tendency of decentralization, due to a recent investment in new public universities in the other Brazilian regions. So, this study sought to present an overview of the scientific production about science education and we expect that this information can help to expand the vision about the development of this research area in Brazil.     

Prediction of the Magnetic Variation Field Based on Multiple Geomagnetic Components

A new method for the prediction of the geomagnetic variation time series based on multiple geomagnetic components is presented in this paper. The method used the data of multiple geomagnetic components (H, D, Z) with different kinds of combination (H, Z; H, D; H, D, Z) from a series of geomagnetic stations to predict the Z component (both in single-step prediction and multi-steps prediction). The comparison and analysis between the new method and the method based on single Z component are done in the paper. The results indicate that the new prediction method based on components (Z, H) has a higher precision than the model based on single Z component.     

Influence of nickel on secondary hardening of a modified AISI H13 hot work die steel

This paper focuses on the effects of nickel on secondary hardening of a modified H13 hot work die steel. Both the non‐nickel steel and the nickel‐added steel get a secondary hardening peak at 520 °C, and the secondary hardening peak trends to increase in the nickel‐added steel. On the basis of scanning electron microscope and transmission electron microscope observation, the rise of the secondary hardening peak is in connection with the precipitation of M₃C type carbides. More strip‐shaped and needle‐shaped M₃C type carbides precipitated from matrix. By means of internal friction, the result suggests that nickel does not affect the position of the Snoek‐Kê‐Köster peak, but the height of Snoek‐Kê‐Köster peak of the nickel‐added steel is higher, which indicates nickel enhances the interaction between dislocations and interstitial atoms, promoting the precipitation of carbides.     

Density Effect of PTFE-Copper Powder Metallurgy Liner Material on the Perforation Performance of Shaped Charge Jets

Strength of Materials - The aftereffect damage efficiency of shaped charge jets formed with the conventional metal liner against light armor is quite low. The validity of the PTFE-copper powder...     

Effects of Saccharomyces cerevisiae fermentation products on dairy calves: Performance and health

The aim of the study was to evaluate the effects of Saccharomyces cerevisiae fermentation products (SCFP) on performance and health of calves during the first 63 d of age. Sixty Holstein calves (30 males and 30 females) at 2 d of age were blocked by sex and date of birth then randomly assigned within blocks to 1 of 3 treatments. A texturized calf starter was fed ad libitum containing 0 (control), 0.5, or 1% SCFP (Original XPC, Diamond V, Cedar Rapids, IA) of DM. In addition, the supplemented calves were fed 1 g/d SCFP (SmartCare, Diamond V) in milk until d 30. All calves were fed 4 L of colostrum within 1 h of birth and were subsequently fed milk twice daily until weaned at 56 d of age. Male calves were harvested on d 56. Performance and health of weaned female calves were monitored until 63 d of age to determine the effect of preweaning treatment of SCFP on weaning stress. Starter intake, fecal scores, and medical treatments were recorded daily. Body weight measures and blood samples were collected on d 2, 28, 56, and 63. Serum was analyzed for blood urea nitrogen, fatty acids, insulin-like growth factor-1, glucose, and total protein. Oxidative biomarkers and total antioxidant capacity were also evaluated in the serum. Body weight, DMI, blood parameters, and oxidative biomarkers did not differ among treatments. Supplementation of SCFP lowered fecal scores in the pre- and postweaning periods. Saccharomyces cerevisiae fermentation products can be used to reduce the diarrhea in calves grown under normal commercial conditions.     

A temporal stable node-based smoothed finite element method for three-dimensional elasticity problems

A stabilized node-based smoothed finite element method (sNS-FEM) is formulated for three-dimensional (3-D) elastic-static analysis and free vibration analysis. In this method, shape functions are generated using finite element method by adopting four-node tetrahedron element. The smoothed Galerkin weak form is employed to create discretized system equations, and the node-based smoothing domains are used to perform the smoothing operation and the numerical integration. The stabilization term for 3-D problems is worked out, and then propose a strain energy based empirical rule to confirm the stabilization parameter in the formula. The accuracy and stability of the sNS-FEM solution are studied through detailed analyses of benchmark cases and actual elastic problems. In elastic-static analysis, it is found that sNS-FEM can provide higher accuracy in displacement and reach smoother stress results than the reference approaches do. And in free vibration analysis, the spurious non-zero energy modes can be eliminated effectively owing to the fact that sNS-FEM solution strengths the original relatively soft node-based smoothed finite element method (NS-FEM), and the natural frequency values provided by sNS-FEM are confirmed to be far more accurate than results given by traditional methods. Thus, the feasibility, accuracy and stability of sNS-FEM applied on 3-D solid are well represented and clarified.     

Reflectance,dielectric constant and chemical content of selected sedimentary rocks

Relationships among average spectral reflectance measured in the visible and near infrared (VNIR) region (0.4-2.5 w m), dielectric constant measured in the microwave region (0.5-18 GHz) and chemical content of 34 sedimentary rock samples were measured. The natural logarithm of the average spectral reflectance and that of the imaginary part of the dielectric constant were negatively correlated ( 𝜌 =-0.60). The average spectral reflectance correlated negatively with Fe2O3 ( 𝜌 =-0.61), Al2O3 ( 𝜌 =-0.63), K2O ( 𝜌 =-0.60), TiO2 ( 𝜌 =-0.64), and P2O5 ( 𝜌 =-0.60). The average imaginary part of the dielectric constant correlated positively with Fe2O3 ( 𝜌 =0.76), K2O ( 𝜌 =0.62), and TiO2 ( 𝜌 =0.70). The average real part of the dielectric constant is highly correlated with the weight loss of the rocks due to burning (burnt loss) ( 𝜌 =0.92), SiO2 ( 𝜌 =-0.96), and CaO ( 𝜌 =0.91).     

Thermal shock behavior of nano-sized SiC particulate reinforced AlON composites

Aluminum oxynitride (AlON) has been considered as a potential ceramic material for high-performance structural and advanced refractory applications. Thermal shock resistance is a major concern and an important performance index of high-temperature ceramics. While silicon carbide (SiC) particles have been proven to improve mechanical properties of AlON ceramic, the high-temperature thermal shock behavior was unknown. The aim of this investigation was to identify the thermal shock resistance and underlying mechanisms of AlON ceramic and 8 wt% SiC–AlON composites over a temperature range between 175 °C and 275 °C. The residual strength and Young's modulus after thermal shock decreased with increasing quenching temperature and thermal shock times due to large temperature gradients and thermal stresses caused by abrupt water-quenching. A linear relationship between the residual strength and thermal shock times was observed in both pure AlON and SiC–AlON composites. The addition of nano-sized SiC particles increased both residual strength and critical temperature from 200 °C in the monolithic AlON to 225 °C in the SiC–AlON composites due to the toughening effect, the lower coefficient of thermal expansion and higher thermal conductivity of SiC. The enhancement of the thermal shock resistance in the SiC–AlON composites was directly related to the change of fracture mode from intergranular cracking along with cleavage-type fracture in the AlON to a rougher fracture surface with ridge-like characteristics, crack deflection, and crack branching in the SiC–AlON composites.