Effect of Magnesia Blending on the Magnetic Properties of Grain Oriented Silicon Steel

Decarburized samples of grain oriented silicon steel were coated with alone and blended magnesias and submitted to the high temperature annealing. The magnesias and their blendings were characterized using granulometry measurements, ignition loss and reactivity tests. After high temperature annealing, forsterite film morphology, magnetic properties and Goss deviation were also analyzed. Better magnetic properties and sharper Goss orientation were found in samples which had used blended magnesias. These results are explained by the magnesias particle size distributions, forsterite film formation and rate of inhibitors release.     

Tissue alterations in the Guinea pig lateral prostate following antiandrogen flutamide therapy.

The flutamide antiandrogenic effects on the Guinea pig male prostate morphology in puberal, post-puberal and adult ages were evaluated in the present study. Daily-treated group animals received flutamide subcutaneous injection at a dose of 10 mg/Kg body weight for 10 days. The control group animals received a pharmacological vehicle under the same conditions. The lateral prostate was removed, fixed and processed for light and transmission electron microscopy. The results revealed an increase of the acinus diameter in the treated puberal animals and straitness in the stromal compartment around the acini. The epithelial cells exhibited cubic phenotype. In the post-puberal and adult animals, a decrease of the acinus diameter was observed, as well as an increase of the smooth muscle layer and presence of the folds at epithelium. The ultrastructural evaluation of the secretory cells in the treated group demonstrated endomembrane enlargement, mainly in the rough endoplasmic reticulum and Golgi apparatus. In addition, a decrease of the microvilli and alterations in the distribution patterns and density of the stromal fibrillar components were observed. In conclusion, the flutamide treatment exerts tissue effects on the lateral prostate, promoting stroma/epithelium alterations.     

Corrosion behaviour of a dissimilar joint TIG weld between austenitic AISI 316L and ferritic AISI 444 stainless steels

The AISI 444 stainless steel (SS) has become an option to substitute the AISI 316L SS because of its low cost and satisfactory corrosion resistance. However, the use of AISI 444 alloy tubes in heat exchangers causes the welding of a dissimilar joint. The aim of this study was evaluate the corrosion resistance of the tube-to-tubesheet welded by a TIG process composed of AISI 316L and AISI 444. Preparation of samples was executed through replication of tube-to-tubesheet joints. In order to test the corrosion resistance of the welded joint, the following tests were applied: sensitisation, mass loss from room temperature up to 90 °C and electrochemical corrosion tests in 0.5 mol/L HCl and 0.5 mol/L H₂SO₄ electrolytes. The results have shown that the dissimilar joint suffers galvanic corrosion with increased degradation of the heat-affected zone of the AISI 444 tube. Nevertheless, the mechanisms of localised corrosion (pit and intergranular) were more active in the AISI 316L alloy. It is concluded that the dissimilar joint showed better corrosion resistance than the welded joint composed solely of AISI 316L at temperatures up to 70 °C, as the conditions observed in this work.     

A Module for BiST of CMOS RF Receivers

A module to perform a built-in self-test in CMOS RF receivers is presented. The module is associated with a test strategy consisting of measuring the main performance parameters of the single building blocks individually. Circuitry overhead, however, is kept low by using some blocks as part of the test set-up and reusing them. The test overhead has also been reduced by replacing direct determination of performance parameters with their estimation. The test methodology has been applied to a mixer in the first down conversion stage of a GSM receiver, estimating its conversion gain, 1dB compression and third-order interception points. Using the output of the IF amplifier as the only testing point, the rms errors in the estimation of the above mentioned parameters are 1.5, 3.0 and 2.7%, respectively.

The Social Media Basis of Youth Protest Behavior: The Case of Chile

Protest activity has become a central means for political change in Chile. We examine the association between social media use and youth protest, as well as mediating and moderating mechanisms of this relationship, using survey data collected in Chile in 2010. We found that Facebook use was associated significantly with protest activity, even after taking into account political grievances, material and psychological resources, values, and news media use. The link between overall Facebook use and protest activity was explained by using the social network for news and socializing rather than when it was used for self‐expression. Postmaterialist values and political ideologies were not found to moderate the association between Facebook use and protest.     

Pyrometer model based on sensor physical structure and thermal operation

This paper proposes a new simplified thermal model for pyrometers, which takes into account both their internal and external physical structure and operation. The model is experimentally tested on the REMS GTS, an instrument for measuring ground temperature, which is part of the payload of the NASA MSL mission to Mars. The proposed model is based on an energy balance equation that represents the heat fluxes exchanged between sensor elements through radiation, conduction and convection. Despite being mathematically more complex than the more commonly used model, the proposed model makes it possible to design a methodology to compensate the effects of sensor spatial thermal gradients. The paper includes a practical methodology for identifying model constants, which is part of the GTS instrument calibration plan and uses a differential approach to avoid setup errors. Experimental results of the model identification methodology and a target temperature measurement performance after identification has been made are reported. Results demonstrate the good behaviour of the model, with errors below 0.15 °C in target temperature estimates.     

Modeling shear bands in J2 plasticity using a two‐scale formulation via embedded strong discontinuity modes

A new two‐scale finite element formulation was developed for modeling J₂ plastic deformation processes (2D) in which shear band localizations take place. The formulation is based on the use of embedded strong discontinuity modes, which are triggered using a stress‐based criterion. The new formulation does not require a specific mesh refinement to model the localization phenomena and provides mesh‐independent results. The shear bands constitutive behavior is derived from the continuum properties without the introduction of any ad hoc physical law. Copyright © 2008 John Wiley & Sons, Ltd.