Navegando por Data de Publicação, começando com "2021-05-21"

Filtrar resultados por ano ou mês

Agora exibindo 1 - 10 de 10

Design of high entropy alloys for hydrogen storage: study of the Mg-V-Al-Cr-Ni, Mg-Al-Ti-Mn-Nb and Ti-V-Nb-Cr systems
(Universidade Federal de São Carlos, 2021-05-21) Strozi, Renato Belli; Zepon, Guilherme; https://lattes.cnpq.br/7924187202036614; Leiva, Daniel Rodrigo; https://lattes.cnpq.br/6576844591900987; https://lattes.cnpq.br/1446491958389890
The advent of high entropy alloys (HEA) has brought new opportunities and challenges to metallurgy. Due to extensive compositional field of HEAs, the possibility of controlling properties in a composition-driven approach becomes evident. However, this vast compositional field demands enormous efforts to select promising alloys for a given application. Up to now, an accurate model to effectively designing HEAs for hydrogen storage is still lacking. Thus, this thesis is dedicated to investigating the effects of the chemical composition on the structural and hydrogen storage properties of body-centered cubic (BCC) HEAs for hydrogen storage applications. Firstly, a set of lightweight HEAs of the Mg-V-Al-Cr-Ni system was produced by high-energy ball milling (HEBM). The experimental results indicate that a single-phase solid solution was only obtained for the equiatomic composition. The investigated alloys exhibited poor hydrogen storage properties. This behavior brought to light the importance of balancing hydride- and non-hydride-forming elements to tune the alloy’s hydrogen affinity, specially considering the mean enthalpy of hydrogen solution of the alloying elements. In a second step, a semi-empirical design method was employed to screen a single-phase BCC alloy with high hydrogen affinity from the Mg-Al-Ti-Mn-Nb system. Through the calculation of four composition-dependent parameters (φ, VEC, mean enthalpy of hydrogen solution and mean mean enthalpy ), the Mg12Al11Ti33Mn11Nb33 alloy was designed. When produced by HEBM, this alloy exhibited a single-phase BCC structure and interesting hydrogen storage properties, indicating that the design approach can be successfully applied to find interesting compositional regions for a multicomponent system, decreasing the number of experiments needed to find alloys with appropriate properties for hydrogen storage. In the third part of this study, the effects of adding a non-hydride-forming element in a multicomponent system composed only of hydride-forming elements was investigated. The CALPHAD method was applied to find a suitable alloy system. The (TiVNb)100-xCrx alloy system was selected, with x = 15, 25, and 35 at.%. In this range of composition, the CALPHAD method indicates the formation of single-phase BCC during solidification for the three alloys, which was confirmed experimentally. The hydrogen storage performance was evaluated, and it was verified that increasing the Cr/(TiVNb) ratio leads to significant increase in the equilibrium plateau pressure of the (TiVNb)100-xCrx alloys, without significant loss of maximum hydrogen storage capacity. It was demonstrated that the proportion of a non-hydride forming element can be used to tune the hydrogen storage properties of the HEAs.
Otimização da sensibilidade de detecção de sensores óticos baseados em moléculas fotônicas
(Universidade Federal de São Carlos, 2021-05-21) Junior, Valnir Carlos da Silva; Barea, Luis Alberto Mijam; https://lattes.cnpq.br/7929868663210908; https://lattes.cnpq.br/4925370507459259
The integrated photonics has been consolidated in the last years in part by the ability to meet the recent demand for the miniaturization of photonic devices. Waveguides and optical microcavities stand out among the main components used in integrated photonics. Waveguides consist of structures capable of guiding electromagnetic waves between their starting and endpoints, based on the difference in the refractive indices of two or more materials to keep light confined by guiding them inside the chip. The optical microcavities are simple photonic structures, mostly in the form of disks or rings, which allow the photons to be strongly confined in a tiny volume. Several integrated photonic devices take advantage of the optical characteristics of these structures, which combined, guarantee the design of integrated photonic chips, fabricated in laboratories of universities, companies, and foundries. One of the largest applications of integrated photonic chips is in optical sensors, called lab-on-a-chip, which allows several lab functions on a single chip in order to achieve high-performance automation and screening. In particular, sensors based on photonic molecules (PMs), which are combinations of optical microcavities coupled with each other, use a detection method linked to the variation of resonances of the microcavities in the presence of a change in the refractive index of the environment around the microcavities. The resolution of these sensors is highly dependent on the dimensions of the transverse session of the waveguide where the light is confined. One of the main challenges of this type of sensor is the optimization of its sensitivity, without there being major changes in the fabrication methods to obtain them once they are well established in the industry. In this sense, the focus of this project was to investigate methods to increase the sensitivity of integrated sensors based on PMs from the optimization of the dimensions of the components that constitute them to the implementation of strangulation in the waveguide that forms the detection rings. This strangulation will ensure an increase in the evanescence of the propagating modes in these cavities, responsible for the detection of the sensors, increasing significantly its sensitivities.
Participação social em educação e dominação: uma análise sobre o campo e as implicações do trabalho parrésico
(Universidade Federal de São Carlos, 2021-05-21) Batista, José Ricardo; Silva, Flávio Caetano da; https://lattes.cnpq.br/7889803676083470; https://lattes.cnpq.br/7671024971334446
The discourse about the democracy participation in education asks educators, for instance. This paper on the assumption that the policies actives take on important in all human life, especially, from the participative democracy model. Therefore, we seek to investigate how the mechanisms of social participation in educational public policies have been developed, purposing to understand the resignifies and establish regimes of truths grounded by the speeches. We used dice from official documents, laws among others. In addition to treating parrhesic work as a possibility for the present day, from the perspective of resistance to the governmentalized state. Besed on a theoretical basis in Michel Foucault, we sought to understand the dynamics established by the governmentality that uses institutions, as well as the structures proper to the Democratic State to constitute a homogeneous group that reinforce and expand its Power. One of the sides, which is the parrhesic represent the rupture of that order. It suggesting think that we have ethical experiences that overcome all harassment of normalizing devices. The, we rake up some implications of Foucault's analysis are evaluated to rethink the dilemmas of educational theorization and the role of teachers and education professionals as intellectuals to specific rationality developed today. Consciousness and this practice originated by the antiquity, implies a virtue, a quality and a duty that in the political and educational show as a technique of your own direction. Because of that, this paper examined official documents and some bibliographic references to understand how this transition takes place between intellectual discussion and the formation of a set of laws, projects, opinions, theses and pedagogical / legislative proposals with the scope of unifying thought and that provides the improvement of governmentality. Freedom is a fundamental principle of democracy. For that reason, any form of limitation, restraint and weakening must be repelled by anyone. The centralization at the state level represents a serious threat to freedom. In our reality, we can note a strong centralization. This can make easy the implementation of totalitarianism. Only the strengthening of the individual as an autonomous being can represent a way of resisting governmentality. In the end, we’d like to talk about the role of education in this scheme that we will try to situate in this characteristic game of modernity.
Utilização de grãos secos de destilaria (DDG) como substituto de farelo de soja na fase de terminação de novilhas Nelore
(Universidade Federal de São Carlos, 2021-05-21) Forcin, Tales Monteiro; Stipp, Danilo Tancler; https://lattes.cnpq.br/2930975168886154; https://lattes.cnpq.br/4404135116350937
Brazil presented in 2019 the world’s largest beef cattle herd, but still has great potential for development of this productive chain. Beef cattle supplementation is one of the tools for optimizing the meat production in the country. Accordingly, the use of high rumen undegradable protein (RUP) supplements like soybean meal (SM) and dried distiller’s grains (DDG) on meat production becomes interesting. Thereat, the objective of that study is evaluating the replacement of SM by DDG in terms of productive efficiency during finishing phase beef cattle. Sixty Nellore heifers were used to evaluate their performance submitted 3 different treatments of concentrate supplementation: T1 - conventional SM as protein source; T2 - supplement with 50% replacing SM protein source by DDG, and T3 - supplement with 100% replacement of SM protein source by DDG. During dry season, the finishing developed in grazing system, during 30 days (first moment), which were maintained in Bracchiaria grass pasture, receiving supplementation. Then the last 63 days (second and third moment) were maintained in corn silage, in additional to the same supplementation. In between every moment of 30 days and in the last day of the experiment were collected weight and body condition score (BCS), then animals were slaughtered and collected carcass weight and carcass yield. It was concluded that DDG can partially replace SM in feedlot diets without changing animal performance. The total replacement of SM by DDG, without being accompanied by ingredients that provide a better rumen degradable protein RDP / RUP ratio, can change performance.
O professor de educação especial nos institutos federais
(Universidade Federal de São Carlos, 2021-05-21) Guimarães, Luciana Carlena Correia Velasco; Vilaronga, Carla Ariela Rios; https://lattes.cnpq.br/6536774151778096; https://lattes.cnpq.br/2385112302119235
Special Education is transversal and is foreseen at all levels and teaching modalities, therefore, the presence of the special education teacher must be ensured as one of the actors of this modality. Once, the role of the school and its educators in the schooling of the target audience of Special Education is to effect accessibility, integrally, as school autonomy of diversity in all its manifestations. This research aims to analyze the role of Special Education teachers in Federal Institutes. Specifically: a) Outline the profile of the initial and continuing education of Special Education teachers; b) Describe the possibilities and challenges of the practice of Special Education teachers in research, extension and teaching; c) Describe the functionality and organization of the Specialized Educational Service; d) Analyze the conceptions about the institutional policy in the accessibility actions of the campus. This work consisted of an investigation of a descriptive character, following a qualitative approach, of the field study type, and had as participants 20 teachers in the area of Special Education from 11 Federal Institutes. Based on ethical procedures for research with human beings, the research was authorized under CAAE number: 3.927.464 by the Research Ethics Committee of the Federal University of São Carlos. For data collection, two instruments were used, a questionnaire and a script that was used for the interview, both carried out online. The registered data were treated and analyzed in light of the content analysis approach, and discussed with the scientific literature in the field of Education, Special Education, Political and Social Sciences. As a result, we found that the majority of respondents are graduates in Pedagogy with a postgraduate degree in Stricto Sensu in Education or Special Education programs. The employment relationship has a greater number of effective vacancies. The challenges in working with teaching, research and extension are the organization of the workload in the Individual Work Plan and the lack of human and material resources. Specialized Educational Service is prioritized in teaching, but it is not restricted to teaching activities, with the exception of three Special Education teachers. The completion of this study allowed describing the role of the Special Education teacher at Federal Institutes.
Nanopartículas de ouro funcionalizadas com flavina adenina dinucleotídeo para detecção eletroquímica de dopamina
(Universidade Federal de São Carlos, 2021-05-21) Medrades, Jennifer de Pontes; Ferreira, Marystela; https://lattes.cnpq.br/4714185516263478; https://lattes.cnpq.br/7324777155217947
Dopamine (DA) is a neurotransmitter with multiple roles in the central nervous system, and alterations in its level in the organism result in Parkinson’s and schizophrenia diseases. Therefore, DA levels monitoring in the body is of medical interest. Hence, a novel electrochemical biosensor was designed on a gold substrate with a self-assembled 11-Mua monolayer, a cationic polyelectrolyte (PEI) layer, and a layer of gold nanoparticles stabilized with glutathione and functionalized with flavin adenine dinucleotide (FAD). FAD, a cofactor found in the active site of monoamine oxidase enzymes, was added to this biosensor to make it selective. The developed biosensor was characterized by UV-Visible spectroscopy, FTIR, atomic force microscopy (AFM), and cyclic voltammetry (CV), confirming a successful development process. Differential pulse voltammetry (DPV) data for detection assays using 0.1 mol L-1 (pH 7.4) PBS buffer demonstrated no interference of uric acid, ascorbic acid, serotonin, and urea. The biosensor was stable for 20 days, presenting a linear detection ranging from de 0.8 to 8.0 µmol L-1, 1.25 µA/µmol L-1 cm-2 of sensitivity, and 0.525 µmol L-1 and 1.75 µmol L-1 for calculated limits of detection and quantification, respectively. Human urine was used as a real sample, and the values of recovery ranged from 85 to 90%. In summary, the developed biosensor demonstrated perspectives for being applied in complex sample analyses.
Obtenção de fibras cerâmicas ultrafinas à base de Nb₂O₅ para a fotoconversão gasosa de dióxido de carbono
(Universidade Federal de São Carlos, 2021-05-21) Prado, Ana Carolina Figueiredo; Paris, Elaine Cristina; https://lattes.cnpq.br/8475640212486290; Luz, Ana Paula da; https://lattes.cnpq.br/3470395641242374; https://lattes.cnpq.br/7137947133238899
The increase in global warming rates is worrisome due to the harmful effects on different ecosystems. However, there is a need to reconcile these figures with the demand of industrial society for food, health, leisure, and energy production, which directly/ indirectly contribute to the increase in greenhouse gas emissions. Pollutants such as NOx, CO2, CH4, and others, significantly affect the lives of beings as a whole. One way to minimize these effects is to remove and reuse these pollutants from photocatalytic processes. In this sense, one of the promising materials for application in conversion is Nb2O5, due to its photocatalytic properties, abundance in Brazil, and low cost compared to usual catalysts. The present work aimed to develop a photocatalyst system based on ultrafine Nb2O5 fibers to convert CO2. To obtain the ceramic fibers, the electrospinning method was used, followed by heat treatment. The concentrations of the polymeric solutions and the heat treatment conditions were optimized. For the evaluation of the photocatalytic activity of Nb2O5 fibers in the conversion of CO2, a reactor monitored by gas chromatography was used to quantify the products generated. At the end, the stability of the system was evaluated in view of the number of reuse cycles. Furthermore, when varying the calcination temperature, it was observed that the temperature of 600°C for 2 h was the condition that made it possible to obtain homogeneous nanofibers with average diameters of 84 nm. It was confirmed that the Nb2O5 nanofibers converted CO2 mostly into CO and CH4 at less ratio, with values close to 8.5 μmol g-1 and 0.55 μmol g-1, respectively. In reuse tests, a decrease in CO production was identified until the end of the 4th cycle, whereas for methane these concentrations were not observed. Consequently, photocatalyst nanofibers based on Nb2O5 were obtained, which enabled the CO2 converting process to added value products CO and CH4.
A leitura nos anos iniciais do ensino fundamental: uma análise do manual do professor do livro didático da coleção Novo Pitanguá
(Universidade Federal de São Carlos, 2021-05-21) Carvalho, Beatriz Mendes de; Souza, Geraldo Tadeu; https://lattes.cnpq.br/3516168011612531; https://lattes.cnpq.br/4950930245413416
This course conclusion work aims to analyze reading proposals present in a unit of the textbook teacher manual approved by PNLD 2019 of the Novo Pitanguá - Língua Portuguesa collection (BURANELLO, 2017) of the second year of elementary school. It is a documentary and bibliographic research that takes into consideration, mainly, the different fields of action of the Reading/Listening axis present in the curricular component Portuguese Language of the Common National Curricular Base (BNCC) and the Digital Guide of the National Book and Didactic Material Program (PNLD) of 2019. Sections and subsections of the aforementioned textbook are analyzed to understand the space given to reading and the relationship with the reading competences proposed by BNCC. It seeks to enable a reflection on the importance of knowing the public educational policies and the didactic materials derived from these so the didactic proposals are used in a meaningful way by the researcher professor. The results show that the unit of the book corresponds to what is presented in its review of the PNLD Digital Guide 2019, contemplates the skills and abilities present in the BNCC, is concerned with the multiliteracies, the respect for cultural diversity and considers the reading capacities of second year students without underestimating them.
Modelagem e análise numérica da estabilidade lateral com distorção de vigas mistas de aço e concreto
(Universidade Federal de São Carlos, 2021-05-21) Rossi, Alexandre; Martins, Carlos Humberto; https://lattes.cnpq.br/1665294496138141; Souza, Alex Sander Clemente de; https://lattes.cnpq.br/3572504605209699; https://lattes.cnpq.br/3946998323160911
The most rational behavior of steel-concrete composite beams occurs in the case of simply supported elements, in which the concrete is in compression and the steel profile in tension. However, in the continuous and semi-continuous composite beams, in regions close to supports, negative bending moment arise. In this condition, the concrete is in tension, requiring additional reinforcement, and the steel section in compression, being subject to stability phenomena. The most common stability mode in steel-concrete composite beams is Lateral Distortional Buckling (LDB). The current standard procedures verify the LDB starting from the elastic critical moment determination. And, subsequently, they use design curves, such as those derived from the SSRC (Structural Stability Research Council) or ECCS (European Convention for Constructional Steelwork), to determine the LDB strength of steel-concrete composite beams. However, the technical literature shows that the procedures used to determine the LDB elastic critical moment are limited. In addition, it appears that the use of design curves (SSRC and ECCS) proposed for the analysis of stability phenomena in steel elements, are flawed when applied to steel-concrete composite beams. Therefore, in this work, studies about the LDB behavior of steel-concrete composite beams were developed. The investigations were carried out based on the development of a numerical model using the ABAQUS software. With the numerical model properly validated, the following parameters were investigated: I-section, span under negative moment, influence of thickness and slab type, longitudinal reinforcement in the concrete slab, transversal stiffeners in the I-section web and, different distribution of negative moment. With the development of buckling analyses, the LDB elastic critical moment was analyzed, and with the development of post-buckling analyses, the LDB ultimate moment was analyzed. The results showed that the analytical procedures for determining the LDB elastic critical moment, in majority, are conservative. The same behavior was verified in relation to standard and analytical procedures about to the values of the LDB ultimate moment. Finally, with the database obtained in the numerical study, it was proposed, by means of artificial neural networks and multiple regression, analytical procedures to determine the LDB ultimate moment.
Estado, mercado e a defesa concorrencial: uma análise sociológica das configurações do CADE
(Universidade Federal de São Carlos, 2021-05-21) Casagrande, Diego José; Candido, Silvio Eduardo Alvarez; https://lattes.cnpq.br/0194644249955417; https://lattes.cnpq.br/4156550100749294
The aim of this work is analize the remakings in the CADE´s directors and presidents profile, between 1994 and 2020. It searchs to understand how and what level of intensity the social trajectories of these agentes influenced, directly or indirectly, the agency´s decisions in the sector of Brazilian economic regulation. The research purpose is ruled in the theoretical discussions about the joints that exists between State, market and competitive defense. Historically, when assuming a mediation paper next to the economic field, specially through acting regulatory agencies, the State has became inseparable to the market. From the perspective of economic sociology, therefore, State and market can´t be characterized as antagonistic elements, in view of social, political and legal relationships established between both. In the face of this context, a qualitative research was realized containing the data survey about the trajectories of 62 advisers who acted in CADE in th focused period. In order to achieve the proposed central objective, it was used as a base the sociology concepts of Pierre Bourdieu. These data were analized for the production of descriptive statistics and through Multiple Correspondence Analysis (MCA). So, this study demonstrated, in theirs results, that CADE postions in the Brazilian competitive sphere are not ruled only in the legal and political aspects that encompass the organ, but essencially in the settings that envolve the social, cultural and symbolic constructions of agents that are inserted in it, making possible, thus, the articulation of its functional dynamics.