Otimização Topológica com Termo-elasticidade Utilizando Elementos Tri3

This work proposes a formulation for optimization of 2D-structure layouts submitted to mechanic and thermal shipments and applied an h-adaptive filter process which conduced to computational low spend and high definition structural layouts. The main goal of the formulation is to minimize the structure mass submitted to an effective state of stress of von Mises, with stability and lateral restriction variants. A criterion of global measurement was used for intents a parametric condition of stress fields. To avoid singularity problems was considerate a release on the stress restriction. On the optimization was used a material approach where the homogenized constructive equation was function of the material relative density. The intermediary density effective properties were represented for a SIMP-type artificial model. The problem was simplified by use of the method of finite elements of Galerkin using triangles with linear Lagrangian basis. On the solution of the optimization problem, was applied the augmented Lagrangian Method, that consists on minimum problem sequence solution with box-type restrictions, resolved by a 2nd orderprojection method which uses the method of the quasi-Newton without memory, during the problem process solution. This process reduces computational expends showing be more effective and solid. The results materialize more refined layouts with accurate topologic and shape of structure definitions. On the other hand formulation of mass minimization with global stress criterion provides to modeling ready structural layouts, with violation of the criterion of homogeneous distributed stress

Geração de casos de teste a partir de especificações B

With the increasing complexity of software systems, there is also an increased concern about its faults. These faults can cause financial losses and even loss of life. Therefore, we propose in this paper the minimization of faults in software by using formally specified tests. The combination of testing and formal specifications is gaining strength in searches mainly through the MBT (Model-Based Testing). The development of software from formal specifications, when the whole process of refinement is done rigorously, ensures that what is specified in the application will be implemented. Thus, the implementation generated from these specifications would accurately depict what was specified. But not always the specification is refined to the level of implementation and code generation, and in these cases the tests generated from the specification tend to find fault. Additionally, the generation of so-called "invalid tests", ie tests that exercise the application scenarios that were not addressed in the specification, complements more significantly the formal development process. Therefore, this paper proposes a method for generating tests from B formal specifications. This method was structured in pseudo-code. The method is based on the systematization of the techniques of black box testing of boundary value analysis, equivalence partitioning, as well as the technique of orthogonal pairs. The method was applied to a B specification and B test machines that generate test cases independent of implementation language were generated. Aiming to validate the method, test cases were transformed manually in JUnit test cases and the application, created from the B specification and developed in Java, was tested. Faults were found with the execution of the JUnit test cases

Estudo da deposição de filmes finos de BaTi(1-X)Zr(X)O3 por meio de planejamento Box-Behnken

Ferroelectric ceramics with perovskite structure (ABO3) are widely used in solid state memories (FeRAM’s and DRAM's) as well as multilayered capacitors, especially as a thin films. When doped with zirconium ions, BaTiO3-based materials form a solid solution known as barium zirconate titanate (BaTi1-xZrxO3). Also called BZT, this material can undergo significant changes in their electrical properties for a small variation of zirconium content in the crystal lattice. The present work is the study of the effects of deposition parameters of BaTi0,75Zr0,25O3 thin films by spin-coating method on their morphology and physical properties, through an experimental design of the Box-Behnken type. The resin used in the process has been synthesized by the polymeric precursor method (Pechini) and subsequently split into three portions each of which has its viscosity adjusted to 10, 20 and 30 mPa∙s by means of a rotary viscometer. The resins were then deposited on Pt/Ti/SiO2/Si substrates by spin-coating method on 15 different combinations of viscosity, spin speed (3000, 5500 and 8000 rpm) and the number of deposited layers (5, 8 and 11 layers) and then calcined at 800 ° C for 1 h. The phase composition of the films was analyzed by X-ray diffraction (XRD) and indexed with the JCPDS 36-0019. Surface morphology and grain size were observed by atomic force microscopy (AFM) indicating uniform films and average grain size around 40 nm. Images of the cross section of the films were obtained by scanning electron microscopy field emission (SEM-FEG), indicating very uniform thicknesses ranging from 140-700 nm between samples. Capacitance measurements were performed at room temperature using an impedance analyzer. The films presented dielectric constant values of 55-305 at 100kHz and low dielectric loss. The design indicated no significant interaction effects between the deposition parameters on the thickness of the films. The response surface methodology enabled better observes the simultaneous effect of variables.