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Publicações Científicas e Culturais 22756
Recursos Educacionais 447
Trabalhos Acadêmicos 52827

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Development of a surrogate artificial neural network for microkinetic modeling: case study with methanol synthesis
(Universidade Federal de Minas Gerais, 2024-01-15) Bruno Lacerda de Oliveira Campos; Andréa Oliveira Souza da Costa; Karla Herrera Delgado; Stephan Pitter; Jörg Sauer; Esly Ferreira da Costa Junior
Liquid chromatography-tandem mass spectrometry bioanalytical method for the determination of kavain in mice plasma: application to a pharmacokinetic study
(Universidade Federal de Minas Gerais, 2020-01-15) Juliana Veloso Ferreira; Alysson Vinícius Braga; Renes de Resende Machado; Deborah Michel; Gerson Antônio Pianetti; Anas El-Aneed; Isabela Costa César
Idempotent backward slices: a gsa-based approach to code-size reduction
(Universidade Federal de Minas Gerais, 2025-11-28) Rafael Alvarenga de Azevedo
Compiler optimizations are critical for enhancing the efficiency of programs, particularly for software deployed on resource-constrained systems where code size is a primary concern. This thesis introduces a novel technique for code-size reduction by identifying and outlining recurrent program slices. Our approach leverages the Gated Single Assignment (GSA) form, an intermediate representation that makes both data and control dependencies explicit, to enable the precise extraction of self-contained, executable program logic, which we term Idempotent Backward Slices. The proposed algorithm is implemented as a complete, functional, and open-source, out-of-tree pass for the LLVM compiler infrastructure. To evaluate its effectiveness, we conducted a rigorous empirical study, compiling 2007 programs from the LLVM Test Suite. The results demonstrates that our technique achieves significant code-size reductions in specific, targeted cases where other optimizers fail. We conclude that GSA-based slicing is a viable but specialized tool, best suited for domains where code footprint is paramount and code bases contain the recurrent computational patterns our slicer is designed to identify.
Study of the discontinuous galerkin time-domain method applied to electromagnetic problems involving dispersive materials
(Universidade Federal de Minas Gerais, 2025-05-07) Tiago Vilela Lima Amorim
The discontinuous Galerkin time-domain (DGTD) method is a promising technique for solving electromagnetic problems, particularly electromagnetic wave scattering. This approach discretizes the domain into non-overlapping elements. Within each element, the solution uses high-order polynomial basis functions, continuous internally but discontinuous across element boundaries. The resulting system of semi-discrete ordinary differential equations is advanced in time using an explicit step-by-step scheme. A key feature of this process is that each time step involves solving only local problems within each element, contributing significantly to the method's efficiency. This methodology offers several distinct advantages, including its inherent flexibility for handling complex geometries and its straightforward adaptability to non-uniform grids with local refinement. High accuracy is achieved through the use of high-order basis functions. Furthermore, the discontinuous Galerkin method is computationally efficient, often requiring less memory compared to other discretization techniques like traditional finite element methods. The efficacy of the DGTD method has been validated across a wide range of applications, encompassing scattering analysis for both simple and complex objects, wave propagation studies, and antenna modeling. The framework has also proven adaptable, successfully incorporating various essential boundary conditions, such as perfectly matched layers (PMLs) and other absorbing boundary treatments for domain truncation. This research specifically focuses on advancing the application of the DGTD method to the analysis of complex media, with a primary emphasis on frequency-dependent (dispersive) materials and PMLs. Both of these are incorporated into the DGTD formulation through the use of auxiliary differential equations. The main goal is to enhance the DGTD method's utility for electromagnetic simulations involving these challenging material types. The central contribution of this thesis lies in the extension of conventional uniaxial PMLs to novel dispersive uniaxial PMLs. In this advanced formulation, both the material dispersion and the frequency dependence within the PML itself are represented using the complex conjugate pole-residue model. This unified and modular modeling approach, potentially leveraging efficient parameter extraction techniques like vector fitting, facilitates easier integration and enables more accurate and robust DGTD of wave interactions in complex, anisotropic, dispersive environments.
Modelagem e validação experimental do tratamento de efluente ácido com sulfato de magnésio utilizando Metsim® para reuso de água
(Universidade Federal de Minas Gerais, 2025-06-28) Carolina Maia Coelho
Process water reuse depends on its chemical characteristics. Effluents containing sulfates and magnesium are commonly found in hydrometallurgical processes. The precipitation of magnesium (Mg) from sulfate-containing solutions through the addition of quicklime (CaO) produces a residue with a high content of gypsum (CaSO₄·2H₂O) and magnesium hydroxide (Mg(OH)₂). This work presents a study of the chemical variations of the precipitate through simulations using the METSIM® software and a comparison with the characterization results of a residue obtained in a laboratory-scale setup. The results showed that in the simulated process, for a magnesium removal efficiency of 65.8%, there is still a considerable increase in the amount of this element in the feed to the neutralization circuit. On average, for the design magnesium removal efficiency (94.0%), the resulting residue would be composed of 73.3% CaSO₄·2H₂O and 19.2% Mg(OH)₂. In the experiments, a crystalline precipitate was obtained, composed mainly of calcium (34.4% CaO) and magnesium (13.1% MgO), with a true density of 2.33 g/cm³, a D90 of 27.7 µm, and consisting of the gypsum, portlandite, and brucite phases.

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