Browsing by Issue Date, starting with "2023-03-22"

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Máquinas de vetores suporte com aplicação em classificação de crédito
(Universidade Federal de São Carlos, 2023-03-22)
Brandini, Bruno Matheus
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Zuanetti, Daiane Aparecida
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https://lattes.cnpq.br/8352484284929824
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Ferreira, Ricardo Felipe
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https://lattes.cnpq.br/2355076087945221
The credit granting represents one of the products with the highest profitability within a financial institution. However, to ensure profit, institutions must know to whom they lend their capital. In this scenario, a fundamental tool to assist in decision-making regarding the granting of funds is the credit risk which purpose is to predict the creditworthiness of a borrower, classifying the customer as non-defaulting or a defaulting customer. Therefore, this tool must reproduce results close to reality with a low margin of error to avoid financial losses for the credit-granting institution. Nonetheless, in the context of credit analysis, the databases used in the credit risk contain more observations referring to non-defaulting customers (majority class) than defaulting customers (minority class) turning them imbalanced and prone to lead to bias in credit risk. Alternatives to overcome such bias in the classification and adequately deal with the problem of class imbalance is to apply a pre-processing in the data set to balance the classes or modify the classification algorithm. Therefore, in the credit risk context, this work proposes to apply the support vector machine classifier in the discrimination of customers requesting a loan, comparing the performance of this technique both in balanced and imbalanced data sets. In the former will be used the oversampling SMOTE method and in the later the cost-sensitive support vector machine methodology since it is proposed to deal with imbalaced classes. Furthermore, this work compare the performance of the support vector machine classifier with other classifiers commonly used in the credit scenario, such as logistic regression and random forest. The study will be applied to real data and evaluated regards to some metrics that measure the prediction performance.
A influência de compostos orgânicas voláteis de tintas imobiliárias na qualidade do ar de ambientes internos
(Universidade Federal de São Carlos, 2023-03-22)
Oliveira, Victoria Thereza de
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Oliveira, Luciana Camargo de
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https://lattes.cnpq.br/6238603150964753
Considering that people have spent most of their time indoors, it becomes essential to identify the quality of the air they are exposed to during this period. In this context, there are several sources and types of pollutants for indoor air, volatile organic compounds standing out as the most relevant class of these pollutants. The present study aimed to evaluate volatile organic compounds in architectural paints, which is present in the majority of homes, and their influence on indoor air quality. For this, through a bibliographic review in the Web of Science and ScienceDirect database, 21 articles were selected for the investigation the composition of the air in residences in different countries, the volatile organic compounds found attributed to architectural paints and the influence of the residents' health. In that way, it was found that newly painted homes have higher levels of volatile organic compounds, up to 4% of the volatiles found in air samples from homes can be attributed to paints and their main volatiles such as xylene and ethylbenzene. In addition, it was identified as an effect to the great exposure of inhabitants of houses with low indoor air quality, diseases such as the sick building syndrome.
Proteínas modificadoras de sabor: produção recombinante e suas aplicações biotecnológicas
(Universidade Federal de São Carlos, 2023-03-22)
Silva, Lucas Sostena Carvalho
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Fuentes, Andrea Soares da Costa
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https://lattes.cnpq.br/2426157257540389
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https://lattes.cnpq.br/3546112270888801
A class of sweet-tasting proteins from tropical forest plant fruits has been studied for their sweetening potential and also for their taste-modifier activity. The taste-modifier proteins have the ability to change bitter and sour tastes into sweet ones. The characterization of these proteins has already been studied in recent years, as well as the action of taste-modifier properties on human taste receptors. As sweet-tasting proteins and taste-modifiers have low or no caloric content, they have been identified as potential substitutes for sucrose by the food industries aimed at consumers who aim for a diet with dietary and diabetic purposes. Diabetes, obesity and metabolic syndrome have gradually intensified in recent years in Brazil and in the world, and taste-modifier proteins have emerged as an important alternative in the fight against diseases related to excessive consumption of conventional sugar. The production of this class of proteins has already been discussed and it is known that obtaining them from natural sources represents a logistic and economically unfavorable barrier when compared to production by recombinant expression. Therefore, the present work aimed to review the state of the art in relation to sweet-tasting proteins and taste-modifiers known so far, their potential biotechnological applications and barriers that such recombinant products will have to face before being commercialized.
Chatbots: a importância do processamento de língua natural para a experiência do usuário
(Universidade Federal de São Carlos, 2023-03-22)
Oliveira, Ester Gonçalves
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Vale, Oto Araújo
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https://lattes.cnpq.br/2277403284693571
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https://lattes.cnpq.br/1210996103255992
The chatbot market has been showing exponential growth in the Brazilian territory in the last five years, going from 8 thousand chatbots created in 2017 to 60 thousand in 2019, 101 thousand in 2020 and 216 thousand in 2021. The growth of the automated service, within the context of the COVID-19 pandemic, forced most branches of work to adapt to a new re- mote reality. Understanding the current scenario and the exponential in- crease in the use of virtual assistants, it's necessary to highlight the rela- tionship between NLP and the area of chatbots and its importance during construction, development and guarantee of a good user experience. Therefore, this work aims to explain the role of NLP within the chatbots and UX design market, as well as to contribute to the area of linguistics and computational linguistics.
Manifestações patológicas em pisos de concreto: estudo de caso de um galpão industrial
(Universidade Federal de São Carlos, 2023-03-22)
Silva, Júlia Barboza da
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Ferreira, Fernanda Giannotti da Silva
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https://lattes.cnpq.br/0329487394818763
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https://lattes.cnpq.br/1616427157858995
Industrial floors have been widely used in various sectors of the economy. The need for a logistical system for storage, distribution and production was what drove the advancement in the technology of designing and executing industrial floors. Good executive practices influence the result of the work and the absence of them can cause great damage. The cost of corrective maintenance is greater than the cost of preventive maintenance. This work carries out a study of the pathological manifestations in concrete floors, analysis of the possible causes from the conception to the execution stages, as well as how to minimize or correct them. The floor of a shed located in the Sao Paulo’s metropolitan region has been analyzed, and the identified problems are associated with the lack of a specific project and low quality of execution. Unprotected joints were the main cause of most of the pathological manifestations that had been analyzed, representing 47% of the identified problems. Maintenance and repairs need to be carried out before the problems get worse and make the use of the shed unfeasible.
Análise da confiabilidade do transporte público durante a pandemia de COVID-19 na cidade de São Carlos/SP
(Universidade Federal de São Carlos, 2023-03-22)
Vatanabe, Gabriel Voltani
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Hirosue, Fernando Hideki
;
https://lattes.cnpq.br/4091598921285700
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https://lattes.cnpq.br/6372498447265315
The present work has as its theme the analysis of the reliability of public transport during the COVID-19 pandemic in the city of São Carlos/SP, aiming to understand and classify the functioning of the current public transport, through the analysis of its reliability, through the collection of data referring to the times provided and the actual ones, and user satisfaction, through a satisfaction survey. In order to obtain a better overview of reliability, this survey was carried out on different weekdays, as well as at different times, seeking to encompass both peak hours and times between peaks. After obtaining the data, a comparison was made with the data obtained by Sasaya (2018) in the pre-pandemic period, to assess the impact of the pandemic on the service offered. A travel rate within the defined interval, up to 5 minutes late or 3 minutes early, of 55.2% was obtained, while in the comparison period it was 48%. Thus, it is concluded that the reliability of public transport in the city of São Carlos is considered low, since the value of trips within the obtained interval is less than 97%, a value taken as a reference in the analysis. The user satisfaction survey is consistent with the field result obtained, since 66% of the people interviewed indicated some degree of dissatisfaction.
Matemática Chinesa como ferramenta de apoio ao ensino de matemática em escolas públicas
(Universidade Federal de São Carlos, 2023-03-22)
Silva, Liliane Feitoza Bispo da
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Salvador, José Antonio
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https://lattes.cnpq.br/2487171069472158
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https://lattes.cnpq.br/9731361659597751
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https://orcid.org/0009-0003-9566-0916
This work aimed to recover and deepen essential mathematical skills described in the Currículo Paulista in two different educational units. We developed a sequence of five adapted activities inspired by chapters from the book "The Nine Chapters on the Mathematical Art" by Liu Hui, written in the 2nd century AD, using the History of Mathematics with a focus on Chinese Mathematics as the main methodology. The activities were designed to relate the content of each chapter to the skills outlined in the Currículo Paulista, allowing students from both units to experience this approach in the teaching and learning process. The first unit, Fundação Casa, with multi-grade classes, implemented the activities with the aim of deepening and recovering skills. On the other hand, the second unit, a full-time school with students enrolled in their respective grade levels, developed the activities as part of a school action plan, aiming to improve results in the Mathematics discipline. Throughout the process, students made progress in their recovery and concluded the sequence by producing manipulative pedagogical products. However, the most comprehensive outcome was achieved in unit 2, as the sequence of activities was implemented in all classes of the Middle School. This progress was officially announced by the Department of Education of the State of São Paulo.
Impacto da adoção do teletrabalho na cultura organizacional de uma corretora de investimentos
(Universidade Federal de São Carlos, 2023-03-22)
Gonçalves, Gustavo Henrique
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Guimarães, Márcia Regina Neves
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https://lattes.cnpq.br/9250214706491925
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https://orcid.org/0000-0001-8471-3216
With the advance of Covid-19 cases in Brazil, following health recommendations, many companies implemented the telework model. This article seeks to understand the influence of the implementation of this work model on the organizational culture, considering how the adaptation process was done, the performance and behaviors of workers at an investment brokerage firm. The study was made through interviews with ten company managers, using a pre-structured script. It was noted, through the study, that the social relations between workers were especially affected by the change. With this, it was also observed that employees distanced themselves from the company's culture, with a reduction in the evaluation of employees' fit to the company's values, which has as much the potential to reduce employee satisfaction as generate a reduction in competitive differentials, a less collaborative and less innovative work environment.
Ninhos artificiais não substituem cavidades naturais para aves em remanescentes de vegetação nativa em matriz antropizada no sudeste do Brasil
(Universidade Federal de São Carlos, 2023-03-22)
Pedro, Mayara Kelly Do Prado
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Piratelli, Augusto João
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https://lattes.cnpq.br/4747322084219058
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https://orcid.org/0000-0003-0268-4007
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https://lattes.cnpq.br/5297004303991620
Natural cavities in hollows are found in dry trunks, living trees and in the soil, being able to serve as shelter and reproduction places for several animals, including birds. With the advance of urbanization, these cavities have become scarcer, directly affecting the reproductive dynamics of birds that depend on this resource. In this way, the introduction of artificial nests could be a possible alternative to replace natural cavities in hollow ones and, thus, mitigate the effect of their scarcity. In this work, we evaluated the successful occupation by birds of 84 artificial nests made from dry cashew fruit (Lagenaria siceraria) and wooden boxes, installed in two remaining areas of native vegetation in the city of Sorocaba, SP. The nesting rate by birds was 3.57% (n=3) in the two monitored areas, with only the wren (Troglodytes musculus) nesting. Explanations why the results obtained in this work were not very expressive consist of the pre-existence of environmental filters due to the growing anthropic effect; in the installation of artificial nests in small and medium-sized trees; and the possible microclimate inside the nests.
Projeto e análise do desempenho de uma matriz-protótipo para deformação plástica severa de metais por extrusão em canal angular com torção
(Universidade Federal de São Carlos, 2023-03-22)
Teixeira, Rafael Fernando
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Rubert, José Benaque
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https://lattes.cnpq.br/1726311467903505
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Magalhães, Danielle Cristina Camilo
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https://lattes.cnpq.br/5486724956564584
The emphasis of this work was to develop a prototype of a Twist Equal-Channel Angular Pressing die (T-ECAP). ECAP consists of pressing a metallic billet through two sequential channels with same cross-section area forming an angle, imposing large shear strains on the material without significant changes on their initial dimensions. In addition, it is widely studied due to its ability to produce ultrafine-grained materials (< 1 μm). T-ECAP has a twist zone in addition to the sequential channels, so that in each pass a combined shear strain is applied, increasing equivalent strain per pass. In this study, in an original die for T-ECAP, extrusions were made with Cu-0.7Cr-0.07Zr alloy and pure copper, which are very ductile at room temperature, for comparison with the results from numerical simulation obtained by finite element method in a Deform® software. The processed materials had their microstructure studied by metallography and strain distribution was evaluated by Vickers hardness mappings. Performance analysis of the T-ECAP die were also carried out with numerical simulations being performed with different combinations of geometries. The results indicated that in the original ECA-T die a single pass resulted in an equivalent strain of approximately 0.61, using the combination φ = 120° and Φ = 44° in the ECAP zone and ω = 45° and β = 23° in the twist zone. For T-ECAP die optimization, among analyzed combinations, the one that resulted in a smaller heterogeneity in the distribution of stresses and strains with a smaller pressing load was a die with φ = 120°, Φ = 22°, ω = 90° and β = 25°, imposing an average equivalent strain of 1.12 per pass. Thus, based on these findings, a mechanical design of a new T-ECAP prototype die was proposed.
Design, processing, and characterization of high strength precipitation-hardened CrCoNiAlTi high entropy alloys
(Universidade Federal de São Carlos, 2023-03-22)
Santana, Diego de Araujo
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Kiminami, Claudio Shyinti
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https://lattes.cnpq.br/5443002033733395
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https://orcid.org/0000-0001-8231-7316
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Coury, Francisco Gil
High Entropy Alloys (HEAs) have been attracting considerable interest in literature. While early studies focused on producing single-phase HEAs, more recent investigations have expanded to multi-phase compositions to take advantage of precipitation hardening or other benefits of having multiple phases in the microstructure. In this work, two approaches were used to design precipitation-hardened HEAs with an FCC matrix and L12 precipitates. In the first approach, the focus was to introduce L12 precipitates into a highly concentrated Cr-Co-Ni matrix. The Cr29.7Co29.7Ni35.4Al4.0Ti1.2 (at. %) alloy was designed using the CALPHAD method by replacing some Cr, Co, and Ni with Al and Ti, so that an FCC+L12 field was stable at high temperatures. This alloy was produced, processed, and characterized. The results showed that the precipitates were effective in increasing the yield stress of the alloy by about ~55% compared to its homogenized counterpart. Moreover, this approach yielded insights for designing new precipitation-hardened HEAs with optimized strength. In this context, a second approach was proposed to effectively explore the large compositional landscape typical of these multi-component systems and design strong HEAs with an FCC matrix and L12 precipitates. Specifically, thermodynamic calculations using the CALPHAD method were used to screen a series of Cr-Co-Ni-Al-Ti alloys. A total of 11235 compositions was analyzed. After applying specific filtering criteria, the remaining alloys had their solid solution hardening and maximum precipitation hardening contributions to yield strength estimated. To assess the effectiveness of the proposed methodology, three alloys were selected, processed, and characterized using various microstructural and mechanical characterization techniques. The good qualitative agreement between the results and predictions suggests that the approach taken in this study has the potential to significantly expedite the identification and development of new precipitation-hardened alloys with optimized mechanical properties, making it a promising pathway for future research.
Ecologia queer: uma revisão bibliográfica sistemática
(Universidade Federal de São Carlos, 2023-03-22)
Prado, Lucas Baggio do
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Borsatto, Ricardo Serra
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https://lattes.cnpq.br/5988987575101933
Queer ecology is born from the intersection between queer theory and environmental issues, aiming to question the hierarchy that builds our worldview and our interactions with the environment, in order to propose new ways of perceiving the relationships between nature, human beings and sexuality. Therefore, the research proposal aimed to investigate, through a systematic literature review (SLR), the scientific production referring to queer ecology. The SLR was elaborated according to the following steps: 1) elaboration of the questions to be investigated, 2) collection of articles, 3) filtering of studies based on their relevance, 4) analysis of research and 5) synthesis of results. The StArt software was used in order to manage the collected content. Through the present analysis, it is concluded that the adherence of queer theory to environmental and ecological studies contributes to the understanding of the relationship between gender and society within the different ecological systems.
Teoremas limite para variáveis aleatórias de Bernoulli dependentes
(Universidade Federal de São Carlos, 2023-03-22)
Rezende, Bruna Luiza de Faria
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Gava, Renato Jacob
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https://lattes.cnpq.br/0494315910583969
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https://orcid.org/0000-0002-4157-425X
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https://lattes.cnpq.br/2226150553745863
In this work, we consider a sequence of correlated Bernoulli variables whose probability of success for the current trial depends conditionally on previous trials. This conditional probability is given as a linear function of the sample mean and has two parameters of which one can assume negative values. We established for this model the strong law of large numbers, an almost sure and L^p convergence, a Gaussian fluctuation of the sum of the random variables with the proposed distribution, an almost sure invariance principle and a weak invariace pinciple, the central limit theorem and the law of the iterated logarithm. Furthermore, we apply all our results to the minimal random walk, a physical model with interesting diffusion characteristics.
Um estudo sobre consumo de energia em aplicações JavaScript: Identificação dos custos energéticos para a etapa de integração continua
(Universidade Federal de São Carlos, 2023-03-22)
Vellone, Fabricio
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Endo, André Takeshi
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https://lattes.cnpq.br/4221336619791961
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https://lattes.cnpq.br/3743215808709027
Given the climate context that the world finds itself in, controlling the energy consumption that humans perform on a daily basis is indispensable for the well-being of the planet and sustainability. For software this is no different. This work aimed to analyze the energy consumption in the Continuous Integration process of JavaScript applications. In particular, each step of the process was studied, identifying how energy consumption is distributed, tracing a relationship between the execution time of the steps and energy consumption, in addition to making parallels between these consumptions in the software world and the energy consumption of everyday life. First the energy consumption capture tool perf was selected. Next, JavaScript projects were selected for analysis following some specific criteria, such as the existence of different tests and CI, as well as standardizing all existing nomenclatures in these projects. Finally, the chosen tool was combined with scripts to obtain the raw data and the analysis was performed using spreadsheets. It was possible to verify that the testing stages were the most costly among the stages evaluated. For the relationship between time and energy consumption, it was observed that the energy consumption tends to be linear with time for direct processing, and the non-direct processing tends to present a logarithmic pattern of behavior. Furthermore, it was seen that a project can have, on average, the same energy consumption as a hair dryer and can consume more than a router or an Internet modem. Finally, it was identified that at large scales, these energy consumptions can be significant and attention should be paid to the number of times IC pipelines are run throughout a project development. It can also be observed that the higher the complexity of a test type, the higher its cost in terms of energy, going according to the testing pyramid.
Sistema de aproveitamento de águas pluviais (SAAP): análise da viabilidade técnico-econômica e influência no IPTU-Verde em um empreendimento da faixa 3 do Programa de Habitação Popular da Caixa Econômica Federal no município de Limeira/SP
(Universidade Federal de São Carlos, 2023-03-22)
Souza, Daniel Henrique da Silva
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Barreto, Douglas
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https://lattes.cnpq.br/7369326190168139
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https://orcid.org/0000-0001-7079-2048
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http://lattes.cnpq.br/9653243091666796
Rainwater harvesting is an appealing strategy in the context of the water crisis and growing public awareness. Consequently, techniques and methods are being developed to enhance the efficiency of rainwater harvesting systems (SAAP). While acquiring such a system requires a significant initial investment, the fact that a large portion of the Brazilian population is low-income makes rainwater harvesting financially unfeasible for many. Social housing programs (HIS) help these families achieve homeownership, and "Green Property Tax" (IPTU Verde) initiatives can provide them with tax benefits. The challenge lies in optimizing the relationship between the space occupied, implementation costs, and system operation for an SAAP within a "Tier 3" development under Caixa Econômica Federal’s low-income housing program in the municipality of Limeira, São Paulo. This study aims to evaluate—using computational analysis via Netuno software—the feasibility of implementing a rainwater system in a project under the Federal Government's *Minha Casa, Minha Vida* program. It also analyzes the cost-benefit ratio, taking into account the tax relief provided by Bill No. 162/2020. Reservoir volumes were calculated for three scenarios; Scenario 3 proved to be the most viable in terms of construction and alignment with the developer's policies, factoring in rainwater usage for garden irrigation and the cleaning of common areas. The acquisition of the SAAP, combined with the other sustainability features already adopted by the construction company, resulted in a 50% discount on property taxes (IPTU)—with 10% attributed solely to the implementation of the SAAP, in accordance with the provisions of Bill No. 162/2020 ("Green IPTU"). Following system sizing calculations and an assessment of estimated implementation costs, the ratio between the tax benefit gained and the implementation cost was determined to be 84.95%, thereby rendering the operation both technically and economically viable.
Desenvolvimento de um magneto-imunoensaio microfluídico com detecção eletroquímica para diagnóstico de hanseníase
(Universidade Federal de São Carlos, 2023-03-23)
Almeida, Sthéfane Valle de
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Moura, Juliana Ferreira de
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https://lattes.cnpq.br/7928520348050421
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https://orcid.org/0000-0003-1532-2304
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Faria, Ronaldo Censi
Leprosy is an infectious disease caused by the bacteria Mycobacterium leprae and its diagnosis is mostly performed by clinical examination. Thus, in this work, two magnetoimmunoassays were developed for the serological diagnosis of leprosy using amperometry and a disposable microfluidic device. The electrodes produced proved to be accurate, robust and stable for up to 70 days after screen printing. The peptides were conjugated to the surface of magnetic particles (pep/MP), being added to the serum sample to capture the anti-M. leprae. The first immunoassay used a peptide sequence derived from the 85B protein. The final bioconjugate was added to the electrode manually using a micropipette. Electrochemical detection used horseradish peroxidase (HRP) with H2O2 and hydroquinone (HQ) detection solution. The second immunoassay used a peptide sequence derived from the recombinant protein ML0405. The final bioconjugate was added to the electrode using an injection pad. Detection was performed with alkaline phosphatase (ALP) and 1-naphthyl-phosphate (1-NPP) detection solution. Precision was evaluated by the responses obtained in different electrodes of the same device, in different devices and on different days of analysis, obtaining values of relative standard deviation (RSD%) between 4.8% and 13.6%. Analyzes of healthy, PB and MB samples were performed. Both immunoassays showed excellent selectivity and specificity to identify positive patients, including PB. The first trial distinguished PB from MB patients, which makes it also applicable to disease classification. The magneto-immunoassays showed an excellent discriminatory capacity between positive and negative patients, being able to even identify PB patients with high sensitivity, specificity and precision. Thus, they have the potential to guide the appropriate treatment, improving the quality of life of patients.
Análise dos índices de acidentes rodoviários brasileiros com óbitos no período pré e pós pandêmico
(Universidade Federal de São Carlos, 2023-03-23)
Steola, Pedro Ferreira
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Hirosue, Fernando Hideki
;
https://lattes.cnpq.br/4091598921285700
;
https://lattes.cnpq.br/8249550349719239
The purpose of this work is to measure possible sudden changes in accident rates during the pandemic period, which characterize atypical situations due to the exceptionality of the event. This measurement is possible in view of national trends of variation in the number of claims and mortality rates. The study utilizes national trends in road accidents and mortality rates, comparing pre and post-pandemic data to gain an overview of the country during that time. The Federal Government provided the data used in this research through filters available on its website, which were divided by year of interest. To gain insight into state-specific data, population and vehicle fleet information was collected. Simple methodology was applied to compare total deaths and death rates per 100 thousand inhabitants and per 10 thousand vehicles. The results show variations in these indices between pre and post-pandemic periods, with no standard observed across the 27 states. However, the North, Northeast, and Mato Grosso regions had an increase in the indexes that could potentially be attributed to negligence in road safety practices, driver behavior, and traffic engineering.
Avaliação do impacto dos modos de trabalho de manipuladores robóticos em série para resolução de redundância
(Universidade Federal de São Carlos, 2023-03-23)
Cordeiro, João Vinicius Martin
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Fontes, João Vitor de Carvalho
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https://lattes.cnpq.br/9473668144091435
Robotic manipulators are increasingly present in the industrial activities of today, being used for various tasks ranging from welding operations to transportation and cargo handling as a whole. Despite being widely used, many times their application is not done in the most optimized way and they do not take into account the best configuration for the handler, causing characteristics such as workspace usage, torque and power consumption are not optimally utilized possible. Starting from the beginning, for a manipulator to be applied in a certain task, it is necessary to do its mathematical modeling in order to obtain the positions of the joints and links of the manipulator, their speeds and respective accelerations, also taking into account the end-effector positions. The definition of joint positions is done using inverse kinematics. The present work carries out this modeling for the case of a serial manipulator of the RRR type, in which, through the calculations made in the inverse kinematics, two solutions to the problem are found, that is, two diferente configurations for the joints of the robotic manipulator, being they are the elbow-up configuration and the elbow-down configuration. These two configurations, in turn, are called the working modes of a robotic manipulator. When assigning the manipulator’s work mode, it is also possible to define the end-effector positions. When the end-effector has more degrees of freedom than the task needs, the phenomenon called redundancy occurs in the task space, so it is possible to optimize the performance using the excess degrees of freedom. This excess of degrees freedom defines a problem with infinite solutions for the joint positions of the robot. The definition of these positions through an optimization process is called redundancy resolution, and can be done through the local method. The local redundancy resolution is the one that observes the gradient of a cost function at each instant of time and decides joint positions from this. With this, this work aims to study the impacts of the two configurations of a robotic manipulator in series on the resolution redundancy to optimize its kinematic and dynamic performance. In addition, through comparisons of the results between the two working modes of the robotic manipulator, it will be possible to visualize which is the most effective working mode for the Cartesian location in which the manipulator is located
Análise por refinamento Rietveld do efeito de diferentes tratamentos térmicos em aço ferramenta A2 fabricado por manufatura aditiva
(Universidade Federal de São Carlos, 2023-03-23)
Braghim, Leonardo do Carmo
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Bianchini, Bruno
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https://lattes.cnpq.br/8443988120967281
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Gargarella, Piter
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https://lattes.cnpq.br/4641435644243916
The Laser Powder Bed Fusion (L-PBF) is an additive manufacturing technique in which a part is built layer by layer. This process is used for producing parts with complex geometries and customizable densities, such as prosthetics, structural components for aircraft and vehicles, or molds and dies for other manufacturing processes. The heat treatment commonly used to increase the hardness of A2 tool steel leads to the loss of refined microstructure when applied to metals manufactured through additive manufacturing. Therefore, due to the peculiar characteristics of additive manufacturing processes, it becomes necessary to develop non-standard heat treatments that increase hardness without compromising the microstructure resulting from the manufacturing process. The objective of this study is to analyze the X-ray diffraction patterns obtained from A2 tool steel parts fabricated using L-PBF for four different heat treatments: modified normative treatment at 540°C, modified normative treatment at 205°C, shallow sub-zero treatment, and, for comparison purposes, the normative treatment used in conventional manufacturing. Similarity was observed among the resulting phases from the heat treatments, with the normative treatment showing the most significant reduction in the retained austenite fraction and lattice parameters. As the atoms gain energy (mobility) with increasing temperature, higher temperatures lead to increased atomic mobility and diffusion, resulting in the rearrangement of atoms within the unit cells and favoring stress relief during tempering. Consequently, samples subjected to higher temperature treatments exhibited a more considerable reduction in lattice parameters.
Obtenção de um híbrido de sílica e colágeno pelo processo sol-gel visando regeneração óssea
(Universidade Federal de São Carlos, 2023-03-23)
Paula, Julia Helena de
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Souza, Adriano Lopes de
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https://lattes.cnpq.br/4671885302437668
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Duek, Eliana Aparecida de Rezende
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https://lattes.cnpq.br/4147198882685212
The bone regeneration materials exploring is constantly increasing due to the lesions from traumas, illness and aging, that can cause serious complications and functionality loss. Biomaterials are used in order to stimulate bone tissue formation, improve bone healing and restructure tissues around the implants. The sol-gel process is a material synthesis technique promoted by the hydrolysis and condensation reactions of inorganic precursors in aqueous solution and it can be effective method for obtaining biomaterials. Thus, the main of this study was to synthesize silica hybrids containing collagen and triethyl citrate (TEC), through the sol-gel process, followed by the addition of simvastatin (SIN), looking for a material with suitable physical and chemical properties for bone regeneration. Furthermore, this system through the sol-gel process has not been reported in the literature yet. Therefore, the silica hybrids containing variations of 2%, 5% and 8% of collagen were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), differential scanning calorimetry (DSC), assay amplitude mechanics, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Macroscopically and through the SEM images it was verified the presence of different concentrations of collagen that interfered in the morphological distribution of the silica hybrids, where irregularities and heterogeneity on the surface of the hybrids was observed, moreover in the sample containing 2% of collagen. TEC contributed to the thermal degradation occurring at higher temperatures and its incorporation was confirmed by FTIR spectra, however the amorphous character of the silica xerogel was not modified even after this incorporation. Collagen also influenced the thermal stability of the hybrids, at higher concentrations greater thermal stability was observed. Collagen dispersive fibers influenced the lack of homogeneity and regularities, which were proven through the DSC curves, mechanical test of mechanics and SEM. The addition of SIN was performed on the silica hybrid with better thermal and mechanical properties, which contained 8% collagen. This drug was completely released in the initial minutes of the controlled release test, and it was not possible to define a release profile. However, the assay was influenced by collagen absorption at the same wavelength selected for the analysis and the released SIN concentration values were extrapolated. Therefore, silica hybrids containing collagen and SIN can be applied in low mechanical strength regions, such as in bone defects, injuries, wear and in fillings as an osteoinducer. Periodontitis, an oral disease that leads to loss of bone mass, is an application suggested.