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Structural relaxation of glass and its influence on other dynamic processes
(Universidade Federal de São Carlos, 2025-01-30) Lancelotti, Ricardo Felipe; Edgar, Dutra Zanotto; https://lattes.cnpq.br/3671237918412066; https://lattes.cnpq.br/1055167132036400; https://orcid.org/0000-0002-6111-6520; https://orcid.org/0000-0003-4931-4505
The effect of chemical composition on the microstructure and mechanical properties of Ti-Nb-Mo thin films deposited by DCMS on AISI 316L substrate for biomedical applications
(Universidade Federal de São Carlos, 2025-01-30) Martinez Orozco, Katherine Judith; Nascente, Pedro Augusto de Paula; https://lattes.cnpq.br/1387043320265189; https://orcid.org/0000-0002-9155-031X; https://lattes.cnpq.br/6301808903391335; https://orcid.org/0000-0002-6938-3463
The aim of this work is to study the effect of chemical composition on the microstructure and mechanical properties of five titanium β-alloys thin films: Ti74Nb21Mo5, Ti74Nb19M7, Ti72Nb19Mo9, Ti67Nb22Mo11, and Ti71Nb29 (as reference) deposited on AISI 316 L substrates. Films having thicknesses of 671 nm, 573 nm, 841 nm, and 963 nm were deposited by means of direct current magnetron sputtering (DCMS). Microstructural characterization was carried out by scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), and grazing incidence X-ray diffraction (GIXRD). The mechanical properties were tested by means of nanoindentation test, residual stress, and potentiodynamic polarization test. In general, homogeneous thin films were obtained with nanometric grain sizes. The films exhibit clusters and pores. Compressive and tensile residual stress were measured, and expressive results correlating with the morphology of the films were found. As more homogeneous the thin film, the higher the compressive stress value. Inverse Hall-Petch relation was observed, explained by the decreasing in the hardness values simultaneously with decreasing in grain size.
ToMAS: Sumarização abstrativa multinível baseada em tópicos usando LLMs
(Universidade Federal de São Carlos, 2025-01-30) Capellaro, Leonardo; Caseli, Helena de Medeiros; https://lattes.cnpq.br/6608582057810385; https://orcid.org/0000-0003-3996-8599; Branco; https://lattes.cnpq.br/1323489363246457; https://orcid.org/0009-0009-0514-2976
Recently, political discussions in Brazil have gained prominence, becoming one of the most debated topics on social media. Factors such as the diversity of themes, the occurrence of events that attract public attention, and the constant increase in the volume of messages have made it challenging to identify in a clear, concise, and objective manner the main topics of the posts. In this context, this study proposes a new automated method that explores the use of automatic topic generation and multi-level summarization techniques using large-scale language models. The proposed method was evaluated to generate summaries from tweets about Brazilian politics collected during the 2022 presidential elections. In addition to the multi-level summarization method, a new summary evaluation method was also proposed, based on the divide and conquer strategy for applying the BERTScore automatic evaluation measure to lengthy texts, which also incorporates the generated sentence size as a weight in the evaluation score. Qualitative and quantitative analyses indicate that the combination of these techniques was able to successfully extract and summarize the main topics, demonstrating great potential to be a useful informative tool in the assessment of different opinions, issues, and topics publicly discussed.
Projeto de um tribômetro para ensaio de atrito e desgaste rotativo ou linear recíproco
(Universidade Federal de São Carlos, 2025-01-30) Rosa, Bruno Barioni Ribeiro; Watanabe, Flávio Yukio; https://lattes.cnpq.br/6492641614740181; https://lattes.cnpq.br/9386719052146610
In the competitive industrial scenario, the search for innovative solutions that provide quality, efficiency, and durability to machines and equipment has demanded investment in research and testing of new materials, components, or lubricants before prototype construction. In this context, tribometers, equipment for testing friction, wear, lubricants, and lubrication regimes, are essential for preliminarily and comparatively analyzing different tribological alternatives under various loading conditions, types of motion, rotation/speed, lubrication, and temperature. The main objective of this work is the development of a low-cost pin-disc type tribometer design aimed at academic applications, with the unique feature of being capable of performing the tests established in ASTM G99-17 and ASTM G133-22 standards. The designed tribometer has two interchangeable modules that allow for performing either rotary or reciprocating linear tests between the tested elements, varying load, rotation, and lubrication condition. The designs and specifications of all components that make up the designed tribometer are presented at the end of the work and the expectation is that the construction and application of the tribometer will enable the development of teaching and research activities in Higher Education Institutions, contributing to the improvement of the training of undergraduate and graduate students in the field of engineering, as well as the development of technological solutions that can bring economic benefits to the industry and society in general.
Aplicação de óleo essencial na preservação de produtos cárneos
(Universidade Federal de São Carlos, 2025-01-30) Valdivino, Larissa Gabrielle Neri; Matos, Andreia Pereira; https://lattes.cnpq.br/6155202940087696; https://orcid.org/0000-0001-9502-116X
Essential oils (EOs), extracted from plant sources such as oregano, rosemary and thyme, have antimicrobial and antioxidant properties that make them promising alternatives for preserving meat products. This paper reviews the application of these oils in the inhibition of pathogenic microorganisms, such as Listeria monocytogenes, Salmonella spp. and Escherichia coli; in the control of spoilage microorganisms, and in the reduction of lipid oxidation, with an emphasis on their integration into emerging technologies, such as edible films and active packaging. In addition, the sensory, nutritional and physicochemical impact of the use of EOs in fresh and processed meats was addressed. The review highlights benefits such as increased shelf life and the replacement of synthetic preservatives, in line with the demands for more natural and sustainable products. However, challenges such as the volatility of compounds and possible sensory alterations are addressed, indicating nanotechnology and encapsulation as potential solutions. It is concluded that EOs, in addition to meeting the demands of the food industry, have broad potential in synergy with other conservation strategies.
Correções de Bartlett baseadas em bootstrap no modelo de regressão Dirichlet com parametrização baseada no vetor de médias
(Universidade Federal de São Carlos, 2025-01-30) Vianna, Vinícius Morgado Rosa; Pereira, Gustavo Henrique de Araujo; https://lattes.cnpq.br/4536501674241631
In parametric regression models, it is common to be interested in testing hypotheses about the values of their parameters. In this regard, the most commonly used test when testing more than one parameter is the Likelihood Ratio Test (LRT). This test can be used, for example, to infer the parameters of the Dirichlet multivariate regression model, which is widely applied in modeling compositional data, i.e., multivariate positive observations summing to one. A problem with this test is that the distribution of its statistic under H0 may not be well approximated by the chi-square distribution in small samples, making the test too liberal. Thus, we consider a model with a specific parameterization of the Dirichlet distribution, where the parameters are a function of the mean vector, and apply a Bartlett correction factor based on bootstrap to the LRT statistic. In this way, the corrected test is expected to have a test statistic whose distribution under H0 is closer to the chi-square distribution, regardless of the sample size. The main objective of this study is to compare the performance of the tests resulting from the bootstrap corrections to the usual LRT. Monte Carlo simulation studies showed that the tests with the applied corrections achieved null rejection rates close to nominal levels in small and moderate sample sizes, while also demonstrating good power. An application on sleep stages illustrates the usefulness of these corrected tests.
Structural relaxation of glass and its influence on other dynamic processes
(Universidade Federal de São Carlos, 2025-01-30) Lancelotti, Ricardo Felipe; Zanotto, Edgar Dutra; https://lattes.cnpq.br/1055167132036400; https://orcid.org/0000-0003-4931-4505; https://lattes.cnpq.br/3671237918412066; https://orcid.org/0000-0002-6111-6520
The physics of the glassy state is governed by two fundamental phenomena. The first is the liquid-to-glass transition, characterized by a kinetic constraint that restricts molecular rearrangement at a low enough temperature (or high enough viscosity), leading to the formation of a glass (unstable). The second is the spontaneous structural relaxation of glass back towards the metastable supercooled liquid state, wherein this constraint is overcome. This thesis investigates the mechanisms and effects of the spontaneous structural relaxation on the atomic configurations and macroscopic properties of single- and mixed-modifier oxide glasses. The research is organized into chapters that focus on: (i) the interplay between cooling rates and structural relaxation, studied using the flash-DSC technique; (ii) the kinetics of structural relaxation induced by physical aging, analyzed through changes in refractive index and ionic conductivity at various temperatures; (iii) the response of enthalpy recovery and refractive index of glasses to up- and down-jumps in fictive temperature, evaluated through the Kohlrausch–Williams–Watts function and the Tool–Narayanaswamy–Moynihan model; (iv) the network connectivity speciation and atomic rearrangements during structural relaxation in silicate glasses, analyzed using Raman and Nuclear Magnetic Resonance spectroscopy; and (v) the impact of slow structural changes due to the phenomenon of structural relaxation on ionic diffusion, which significantly influences the faster process of ionic conductivity in different glasses. The findings highlight the importance of understanding and controlling structural relaxation to design new glasses with optimized properties and ensure the long-term stability of these properties.
Ku phamela (servir) alimentos nas cerimônias é hierarquizar e violentar: uma perspectiva sobre direitos humanos e Estado em Maputo, Moçambique
(Universidade Federal de São Carlos, 2025-01-30) Bila, Josué Julião; Leirner, Piero de Camargo; https://lattes.cnpq.br/3883880276055777; https://orcid.org/0000-0002-6485-027X; https://lattes.cnpq.br/8114794394854674; Machado, Igor José Renó; Lolli, Pedro Augusto; Bevilaqua, Ciméa Barbato; Pinto, Danilo César Souza; https://lattes.cnpq.br/4705450652848752; https://lattes.cnpq.br/6114043331557199; https://lattes.cnpq.br/4525832833791990; https://lattes.cnpq.br/0146541919194332
This thesis examines how and why people serve themselves and are served food at marriage ceremonies in Maputo. I observed the way of ku phamela (serving) in the complex world of those celebrations and even in families, where to serve and be served is to fall into a category, sometimes of “person”, sometimes of “individual”. Observing the categorizations of people and individuals led me to understand the problems related to Mozambique's social structure, where hierarchies, privileges and violence are a symbolic weapon for the (de)qualification of social classes and positions. Perhaps this is the reason why in our state a dhla axurha (eats greedily) whoever is hierarchically superior and whoever has networks of intermediaries, in bureaucratic and political environments. Furthermore, when the Mozambican party-state imposed itself in 1975, even though it embodied the Marxist-Leninist ideology, it was, in practice, swallowed up by the mouth of social history, leaving it to reproduce, homologate and reinforce hierarchies, privileges and violence through its governmental and security apparatuses.