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Efeitos da fotobiomodulação e do exercício de carga constante na sensibilidade barorreflexa, variabilidade da frequência cardíaca e pressão arterial no diabetes mellitus tipo 2
(Universidade Federal de São Carlos, 2019-03-29) Milan-Mattos, Juliana Cristina; Catai, Aparecida Maria; https://lattes.cnpq.br/5801652590531684; https://lattes.cnpq.br/7618794015038906
Study 1 Aim: to evaluate cardiovascular autonomic control through time and frequency techniques in a moderate-intensity constant-load exercise session in healthy and diabetic men. Methods: We evaluated 39 men (40-64 years) divided into 2 groups: GDM2 (n=20, DM2 diagnosis) and GC (n=19, without DM2 diagnosis). The participants performed a 10 min of rest (REST), then the volunteer was positioned on a cycloergometer to start the constant workload test (1 min rest, 3 min warm-up, 6 min exercise at constant workload - EXERCISE, 6 min of cool down, 1 min of rest) followed by a 10 min of rest (RECOVERY). The workload exercise corresponded to 80% of the VO2GET (gas exchange threshold) identified by a previous cardiopulmonary exercise test (CPET). The electrocardiogram R-R intervals (BioAmp FE132) and the peripheral pulse pressure (Finometer PRO) signals were continuously collected throughout the protocol. Stable sequences of 256 points were selected for REST, EXERCISE and RECOVERY. Time domain analysis for the heart rate (HR), diastolic arterial pressure (DAP), systolic arterial pressure (SAP) variability (µ: mean and σ2: variance) and BRS (sequence method), as well as the frequency domain analysis for the HR, DAP, SAP variability (spectral analysis) and BRS (cross spectral analysis) were performed. Results: GDM2 presented lower values of μRRi and higher values of HR, higher value of low frequency in normalized units (LFnu – iRR) and more negative phase (LF) in RECOVERY compared to REST. Conclusion: GDM2 presented cardiovascular autonomic control impairment in RECOVERY, evaluated by HRV and BRS. Study 2: Aim: evaluate the effect of photobiomodulation (PBM) on cardiovascular autonomic control, analyzed by baroreflex sensitivity (BRS) (sequence method) during constant workload exercise and recovery in diabetic men. Methods: Eleven men with DM2 (40-64 years) were evaluated. The constant workload exercise protocol was performed on two different days, with a 14 days interval, to guarantee the PBM washout period. Participants were submitted to PBM (150J/300J/placebo) by light emitting diodes (LEDs), followed by the exercise protocol and equipment described in study 1. PBM was applied to the quadriceps femoral and triceps surae. Stable sequences of 256 points were selected for REST, EXERCISE, and RECOVERY. The BRS was calculated in time domain according to the sequence method (αseq). The comparison between the energies (150J/300J/placebo) and the condition (REST, EXERCISE and RECOVERY) was performed by the Two-Way Anova repeated measures test. Results: There was no interaction between energies and conditions. There was only the effect of the condition (p <0.001), showing that the behavior of αseq was similar regardless of energy. Conclusion: the PBM, previously applied to constant workload exercise test with moderate intensity in DM2, was not able to promote changes in the cardiovascular autonomic control, leading to an improvement of BRS.
Anfíbios do Legado das Águas-Reserva Votorantim, SP
(Universidade Federal de São Carlos, 2019-03-29) Lucas, Marcelo Stéfano Bellini; São Pedro, Vinícius de Avelar; https://lattes.cnpq.br/7404103190291423; Carmassi, Giulianna Rondineli; https://lattes.cnpq.br/1483021311370862; https://lattes.cnpq.br/2898219870805566
The Atlantic Forest is one of the richest centers of global biodiversity and also the most threatened. Despite this, have an expressive biodiversity, with high rates of endemism, related to a variety of microhabitats. The great loss of original forest and intense forest fragmentation are mostly due to anthropogenic action, leaving only 8.5% of its original forest cover. The protection of the remaining forest is a responsibility of public and private Conservation Units (UCs) that are a refuge for the diversity of the biome. The Conservation Units created and managed by private sector (RPPNs) has gained increasing importance in the conservation effort, completing government conservation efforts. The amphibians are among the most diverse and threatened vertebrate group on the planet and, about 7.7% of its species are present in the remaining area of the Atlantic Forest Domain. In the last years, the population decline of these animals has become a notorious worldwide phenomenon whose main causes seems to be: global climate change, disease spread and, mainly, habitat loss. The amphibian’s biodiversity in Brazil is among the largest in the world and in the Atlantic Forest are registered 529 anuran species, found in all the phytophysiognomies of the biome. Legado das Águas are located at south of São Paulo state and have 31.000 ha, considered the largest area of Atlantic Forest under private protection in the country, representing about 1.5% of all remaining fragments of this biome. This work had as objective to present the anurofauna of Legado das Águas – Reserva Votorantim, SP, in order to describe the distribution pattern of the species and the habitat use in the forest reserve. Samplings were carried out between December 2016 and November 2017, in monthly campaigns, through three different methodologies: visual search, auditory search and tadpole’s collection. Samplings were performed during the day and night period, at ten permanent points, added with occasional records. A total of 44 species were recorded in 9 families: Brachycephalidae (3 spp.), Bufonidae (3 spp.), Craugastoridae (1 spp.), Hylidae (23 spp.), Hylodidae (3 spp.), Leptodactylidae (6 spp.), Microhylidae (1 spp.), Odontophrynidae (2 spp.) and Phyllomedusidae (2 spp.). Species richness remained higher in the rainy season and the species presented seasonal pattern. Most of the species registered are typical of forest environments and with arboreal habit, with vocalization sites in marshes and / or lakes. At one of the permanent sampling point were collected specimes belonging to the Hylodidae family for which identification was made through genetic sequencing. The molecular analysis identified two species: Crossodactylus caramaschii e C. werneri. The genetic distance of the sample collected for C. werneri was 1.90%, confirming the occurrence of the species in the studied area, increasing the distribution in 135 km to the south of its present distribution. The studied area presents an anuran high richness, but the period was not enough to register all the species with occurrence for the area, which point to the need of other methods combined to increase the possibility of the capture of species.
O processo de implantação do Ensino de 1º grau instituído pela Lei n° 5.692/71 na rede escolar paranaense: uma análise da documentação do Conselho Estadual de Educação (1971-1975)
(Universidade Federal de São Carlos, 2019-03-29) Estacheski, Joice; Ferreira Junior, Amarilio; https://lattes.cnpq.br/0748545841167046; https://lattes.cnpq.br/5670780017794373
This is a quali-quantitative study based on documental research aiming at analyzing historically the implementation process of elementary schooling instituted by the Law nº 5.692 of 11th August 1971, with the purpose of understanding the historical conditions in which it was enacted in the State of Paraná. The analysis was carried out through the study of Technical Opinions by the Education State Council, issued after assemblies held between 1971 and 1975. Since the Military Government Education Reform, instituted by the 1964 civilian-military coup, enabled the extension of mandatory schooling from 7 to 14 years old, it included legally great part of the population in the institutional formal education process. A legal right that, up to that moment did not assist many of the individuals in the Brazilian society as a whole, therefore, it was necessary to investigate the quantitative relations in which this process was developed. It is a fact that the capitalist production mode, as well as the social organization resulting from it, determines public policies in general. Thus, we sought to understand the historical context in which the civilian, military coup occurred, and the consequent need to establish a new teaching organization, since the government system instituted through agreements with the United States of America aimed, through the education process, to qualify workforce for the expansion of the industrial development in Brazil. Enlightened by Fernandes (2005), Ianni (1984), and Alves (1984), we sought to establish the historical constitution of the Brazilian elite, to evidence their interests towards the State organization and the need to promote the civilian-military coup of 1964 and, consequently, their actions regarding the Education Reforms. Therefore, by carrying out the historical analysis of the education policy created, based on Saviani (2008), Cunha and Góes (1991), and Germano (1993), we evidenced the relations between the politics structured at the time and the urgent need of reforms to guarantee viable strategic conditions to the “national development”. Taking into consideration the strong influence of the Human Capital Theory in the structure of the national education project, we analyzed that concept based on Schultz’s ideas (1973) which were incorporated to the political discourses and to the individuals’ formal education process from the 5th year of elementary school on, when the right to mandatory 8 years of schooling were instituted aiming at qualifying those individuals to the job market, directing them to a compulsory professionalization, and how this project influenced other forms of the school organization, such as teachers’ education and the structural, physical and material conditions of the schools in Paraná. This research collaborates with the academic field, mainly regarding education policies in the history of Brazilian education for pointing out that, even if those policies have been put forward as attainment of rights, in this specific case, the access to eight years of schooling, the capitalist structure led the education process so that it would remain focused on the interests of the elite, since, as a general rule, public education and schooling were destined to the children of the working class, they were established only under precarious conditions, consequently limiting those students access to culture and scientific knowledge.
Otimização robusta e programação estocástica para o problema de roteamento de veículos com múltiplos entregadores: formulações e métodos exatos
(Universidade Federal de São Carlos, 2019-03-29) De La Vega Martinez, Jonathan Justen; Munari Junior, Pedro Augusto; https://lattes.cnpq.br/1328868140869976; Morabito Neto, Reinaldo; https://lattes.cnpq.br/4194801952934254
In this thesis, we study the vehicle routing problem with time windows and multiple deliverymen with uncertainty. In addition to routing and scheduling decisions, this problem involves deliverymen allocation decisions on each route to reduce costs and service times. Parameters such as customer demands, travel and service times are considered uncertain. Thus, we propose new models of static robust optimization, which incorporate measures to effectively deal with the cost-risk trade-off, and new models of two stage stochastic programming with recourse to address this problem. Usually, when applying the concepts of robust optimization and stochastic programming, the number of decision variables and constraints grow significantly in terms of instance size. Consequently, the larger the instances, the greater is the computational effort required to solve the resulting models with general purpose solvers. However, computational effort can be significantly reduced if appropriate exact methods are developed that take advantage of the resulting robust and stochastic models’ structure. For this reason, we propose exact methods based on branch-and-cut and branch-price-and-cut, which are effective to solve literature instances. Numerical experiments based on these instances and risk analysis based on Monte Carlo simulation indicate the potential of static robust optimization to address the trade-off between cost and risk. These experiments also reveal that this approach provides good results, even without complete knowledge of some probabilistic measure of the uncertain parameters. Regarding stochastic programming, the numerical experiments show that it is possible to save important resources by solving the two stage stochastic programming model with recourse rather than adopting simpler strategies based on the expected value. To the best of our knowledge, there is no studies in the literature that have addressed the problem under study in this thesis, with uncertainty in demands, as well as in travel and service times. We believe that developing models and effective solution methods to address the vehicle routing problem with time windows and multiple deliverymen are original and relevant contributions to the state-of-the-art literature, opening up new fields for future research not only for the problem under study, but also for other variants of vehicle routing problem.
Liberdade de expressão em democracias: discursos e sujeitos em redes de comunicação
(Universidade Federal de São Carlos, 2019-03-29) Oliveira, Hulda Gomides; Sargentini, Vanice Maria Oliveira; https://lattes.cnpq.br/1406919572611392; https://lattes.cnpq.br/5875459666335277
In this research we develop an analysis of discourses on freedom of expression constructed in different historical moments (antiquity, modernity and contemporaneity), trying to understand how discursive processes constitute subjectivities in democracies. Thus, we are interested not in a study of the occurrence of the terms "freedom of expression", but rather a discursive diagnosis, in the wake of Michel Foucault, of the dynamics raised in diverse conditions of "free expression", which emerged historically, names: freedom of speech, freedom of communication, freedom of ideas and opinions, freedom of thought and expression. We have seen that, because of their socio-political nature, they are discourses crossed by a series of other elements that constitute contemporary practices of "free expression", such as: a Western political philosophy, with paradigms about what the subject is and what he can express; subjects that are marked by conditions of a democratic regime and "possessors" of constitutional rights; marked by the very conditions of operation of the communication networks in which they are involved, either by the architecture of these networks, which allows practices according to a given spatial arrangement, or by dynamics that at the same time make express and silence. Thus, we consider some common places important for the construction of these discourses, and from this we form our corpus of analysis: first, the Greek agora, with the happening of the polis, considered as the place in which it would be the "free citizen to expressing "- for this, we analyze two texts, Aristotle's Politics, and Pericles' Prayer for the Dead; secondly, modern France, with the event of the French Revolution, which through the Declaration of the Rights of Man and Citizen (material we have analyzed), with a manifestly universal claim, would have won the freedom for the "people to express themselves"; Finally, contemporaneity, which with the event of the creation of social networks, on digital platforms, would be experiencing the democratic apogee of which, now, "anyone can express itself" - in this cut, we analyzed statements inscribed on the Internet, as cyberspace of free expression. For us, this trajectory crosses and constitutes the subjects that express themselves in the social networks of the present, and, precisely considering this, is that we are interested in understanding the formation and the operation of such discursive practices to deconstruct any sacralization of freedom of expression in democracies, either of subjects who express themselves in the name of the city, in the name of men's rights, or in their own name. In order to develop such an approach, we take as an analytical clipping of the present, statements that circulate in Brazil in materialities of Facebook (pronounced as "pronto" and "mimimi"), considering the issue of great circulation in the country at the beginning of the 21st century. Finally, as far as our theoretical perspective is concerned, we assume the parameters of Foucaultian archeogynealogy (as we discussed throughout the text), by enabling us to analyze the relationships between ancient and modern practices that end up objectifying and subjecting the subjects who express themselves in the social networks of the present time, composing, finally, whether by regularities or discontinuities, practices and statements about freedom of expression in the contemporary, through processes of objectification and subjectivation.
Estudo da incorporação de nanopartículas de óxido de zinco e pentóxido de nióbio em polietileno linear de baixa densidade
(Universidade Federal de São Carlos, 2019-03-29) Dantas, Ana Paula Silva; Marconcini, José Manoel; https://lattes.cnpq.br/5373845785326215; https://lattes.cnpq.br/3504205986574268
Linear low-density polyethylene (LLDPE) is one of the most widely used materials in greenhouse covering, due to its low cost and transparency to photosynthetically active radiation up to 80%. However, this polymer also presents high transparency to ultraviolet (UV) and infrared radiation (IR), which is undesirable to the quality of the plants. In this context, the objective of this project was to study the addition of ZnO and Nb2O5 nanoparticles in LLDPE matrix aiming a potential application as greenhouse covering. Firstly, the nanoparticles were synthesized by co-precipitation and hydrothermal (ZnO) and hydrothermal (Nb2O5) synthesis, and their optical and structural characteristics were evaluated. Secondly, the composites were processed in an internal mixer, followed by hot pressing to obtain films, whose structure and optical, thermal and mechanical properties were characterized. The structural characterization showed no phase related to impurities of the nanoparticles, and the optical analysis reviewed that both nanoparticles absorbed UV and IR radiation. The microstructures of the composites showed that both nanoparticles agglomerated in the LLDPE matrix, but only ZnO nanoparticles presented a good distribution. Films containing ZnO had an increase in absorption of UV and IR radiation relative to LLDPE films; however, films containing Nb2O5 did not show a significant increase of these optical properties. The incorporation of nanoparticles also decreased crystallinity, but with an increase in thermal stability. The mechanical properties tended to increase for the composites containing ZnO; however, the addition of Nb2O5 significantly reduced tensile strength and elongation at break due to the presence of agglomerates.
Papaína imobilizada em partículas magnéticas: novos modelos de triagem de ligantes
(Universidade Federal de São Carlos, 2019-03-29) Leandro, Cleiton Silva; Cass, Quezia Bezerra; https://lattes.cnpq.br/9197210255594409; https://lattes.cnpq.br/3185301813080236
Cathepsins, human lysosomal enzymes, are associated with the development of various diseases, and cruzaine is an important enzyme in the development of the protozoan Trypanosoma cruzi, causes Chagas' disease. Cysteine proteases, cathepsins and cruzaine, are known as papain-like, due to their structural similarities and catalytic mechanism. Papain is a commercial enzyme, inexpensive and stable, and thus, it has been used as a model for screening assays for cysteine-proteases’ ligands. As the classical assays for these enzymes are spectrophotometrically-based, herein a direct method for measuring the enzymatic product of the reaction using liquid chromatography hyphenated to mass spectrometry is described. For that, new reaction conditions were employed. Under this condition, in solution papain showed a KM of 52.9 ± 3.12 μM. For developing new assay conditions and considering the advantages of use of immobilized enzymes, papain was covalently immobilized on to magnetic particles (P-MB), producing a bioreactor with a KM of 34.9 ± 3.59 μM. For qualifying P-PB screening assay, 10 known cysteine protease inhibitors including acridones, quinolinones, flavonoids, and dipeptidyl nitriles were screened. Maltose was used as a non-binder of papain. With the exception of maltose that showed no inhibitory capacity, in the solution assay (2,1 x 10-3 U) the percentage of inhibition ranged from 13 to 100%, while with P-MBs (1,4 x 10-3 U) the inhibition range was from 34 to 85%. Ligand Fishing assay, papain bioreactors showed affinity for all known binders of cysteine proteases, and no affinity for maltose. Six of them presented expressive affinity only ratio for the active P-MB, with no retention to inactive P-MB control. The other four binders varied their affinity ratio in the range of 2.0 to 3.5. With the ethanolic extract from the stem of Melia azedarach, 11 compounds were fished, among them catechin and epicatechin. The results herein described demonstrates that papain bioreactors can be used for screening cysteine-proteases’ ligands.
Estudo da influência da oxidação a plasma nas propriedades tribológicas da liga metálica TI-6AL-4V.
(Universidade Federal de São Carlos, 2019-03-29) Siqueira, Rafael Coelho; Rossino, Luciana Sgarbi; https://lattes.cnpq.br/0139027055418391; https://lattes.cnpq.br/2647668991232313
The oxidation thermal or the plasma on the surface of the titanium mean to improve the surface resistance to corrosion and abrasive wear, increase the surface hardness and increase the thickness of the formed oxide. Oxidation treatment is used to improve the biocompatibility of the Ti-Al-4V alloy. This report wants to determine the effect of plasma oxidation on the tribological properties of the Ti-6Al-4V metal alloy and the effect that the pressure and temperature sputtering parameters used during the treatment could on the surface of the oxidized samples. Samples have a metallographic preparation on the surface until a mirror finish is obtained, the samples are cleaned and dried and then it is to put to inside the plasma reactor that using a pulsed DC electric source. First the sputtering is carried out on the samples and the oxidation treatment is carried out in sequence. During the sputtering, two proportions of gases were used: 50% Ar and 50% H2, and 80% Ar and 20% H2. For the oxidation treatment the gas ratio of 60% Ar and 40% O2 was used. The pressures used during the treatment were 1.65 Torr and 3.75 Torr. The temperatures used were 480 ° C, 520 °C, 670 °C and 705 °C. The treated samples and the untreated material were characterized by the Vickers hardness test and scanning electron microscopy and abrasive micro-wear. It was observed that the variation of the gas proportions in the sputtering and pressure during the treatment had no an expressive impact of variation with respect to the thickness of the formed oxides, surface hardness and resistance to the micro-abrasive abrasive. About to temperature, this shows a better influence on the thickness of the oxide formed, the hardness of the surface and the resistance to abrasive micro-wear. Average variation in film growth thickness was of approximately 1,2 to 6,8 μm. The hardness of the treated surface became higher than that of the untreated material under all treatment conditions and the reduction of surface abrasive micro-wear occurred.
Desenvolvimento e avaliação de meios filtrantes com nanofibras eletrofiadas e agentes bactericidas aplicados na filtração de ar
(Universidade Federal de São Carlos, 2019-03-29) Bortolassi, Ana Cláudia Canalli; Béttega, Vádila Giovana Guerra; https://lattes.cnpq.br/0752059622240208; Aguiar, Mônica Lopes; https://lattes.cnpq.br/0431688649128529; https://lattes.cnpq.br/3912491491602236
Filtration processes using fibrous filter media are very used to retain microparticles in a stream air due to its simple use, low operational cost and high collection efficiency. However, the study of submicron particles filtration is still incipient internationally and in Brazil, and also the application of nanofibers in this area. New technologies producing filter media are being developed to achieve high particles collection efficiencies with low pressure drop such as production of filters with nanofibers using the electrospinning process. The electrospinning method is very used among several techniques to produce nanofibers because it is simple and versatile. This method uses electrostatic force to obtain fibers with high contact surface area compared with those produced by other methods. Moreover, it is possible to add particles to the polymer solution using this method resulting in biocide filters. However, one of the difficulties to produce these filter media is the adjustment and control of several parameters which influence on production of the nanofiber as polymer concentration, type of solvent, nanofibers deposition time on the substrate, distance from the collector and electric tension. Therefore, the aim of this work was to develop filter media enable to remove particles in nanoscale and with bactericidal effect using the electrospinning technique. All of the filters of this study were produced using the polymer polyacrilonitrila (PAN) and characterized by Energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), fiber diameter, thickness, porosity, permeability, pressure drop. The analyzes of EDX and XPS were evaluated just to filters with AgNO3, TiO2 and ZnO particles added to PAN solution. After these analysis, efficiency filtration, quality factor and bactericidal effect of filter media were evaluated. The experiments’ results from France showed filters with high efficiency filtration (≈100%), high quality factor (0.04 Pa-1) and bactericidal effect (≈100%) against initial E.coli concentration of 104 CFU/ml. The flow rate and duration of electrospinning relating to filtration efficiency and pressure drop of the filters produced in Brazil were evaluated. PAN2_90 filter reached the highest filtration efficiency (99,91% for diameters of particles of 100 nm) but the highest pressure drop (197,35 Pa-1). Filters developed in this work can be applied in air masks and air purification system, in other words, aiming to remove nanoparticles and bacteria from the environment.
A expressão do sujeito surdo por meio da escrita em língua portuguesa
(Universidade Federal de São Carlos, 2019-03-29) Souza, Christianne Thatiana Ramos de; Lacerda, Cristina Broglia Feitosa de; https://lattes.cnpq.br/9468232016416725; https://lattes.cnpq.br/5947879244550162
The teaching and learning process of writing for and by the deaf is a topic of great interest in the area of research on the education of the deaf. There is a concern about the problems regarding the teaching of Portuguese as a second language, with the quality of the written production of the deaf, with the provision of resources that help the teaching and learning of writing and about the problems of learning the second language. However, the investigation of the functionality of writing for the development of the deaf, as well as the ways in which this the subject expresses himself through writing is still insufficient. In this sense, the overall objective of this study was to investigate the expression of the deaf subject through the writing in Portuguese as a second language. The specific objectives were: to analyze the process of appropriation of the norms of Portuguese as a second language by the deaf, supported by sign language; analyze the expression of subjective contents through the language written by the deaf. For this we collected diaries and texts produced by two classes of deaf students who attended the eighth and ninth year of elementary school II, in an inclusive school of the Program of Bilingual Education for the deaf. This material was part of the activities carried out during Portuguese language classes as a second language. From an indexical analysis of the diaries and texts, we identify reports of emotions, desires, plans, among other aspects that represent indicators of the internal functioning of the subject. We also analyze the interlocutions between the teacher and the students present in the text of the diaries focusing on the characteristics and intentions of the dialogues. The results indicated that the journals and the texts were means of interlocution, enunciation and expression of emotional contents of the subjectivity of the deaf. Writing as a semiotic means of constitution and expression of the subject, favored communication and the elaboration of knowledge and emotions, as well as mediating the conversion of processes of signification into internal processes that form the basis of consciousness. In order for the deaf to acquire written language and be bilingual, it is necessary to guarantee a bilingual education that actually places both sign language and written language in circulation in the school environment favoring the use of both languages and also the process of signification by the deaf.
Eletrocerâmicas de BNBK dopadas com tântalo: processamento, fenomenologia e propriedades de armazenamento de energia
(Universidade Federal de São Carlos, 2019-03-29) Quiroga, David Antonio Barbosa; Silva Junior, Paulo Sergio da; https://lattes.cnpq.br/7418621942217628; https://lattes.cnpq.br/2669823237330082
Global energy demand for high energy storage capability materials associated with the search for lead-free electroceramic materials with suitable properties for applications has become the major topic in functional materials research. In this context, bismuth sodium titanate (Bi0,5Na0,5TiO3, BNT) ceramics have attracted great attention by mimicking some characteristics of dominant material in applications, lead zirconate titanate (PbZr1-xTixO3, PZT).Starting from two compositions belonging to morphotropic phase boundary (MPB) of the ternary system xBi0,5Na0,5TiO3 - 0, 72(1 - x)Bi0,5K0,5TiO3 - 0, 28(1 - x)BaTiO3 (BNBK100x, x = 0, 86 e 0, 88), the Ta-doped (0.01, 0.015 and 0.02 mol) ceramics processing conditions have been optimized and the influence of this cation on the structural, morphological, electric, mechanical and energy storage properties of Ta-doped ceramics was evaluated. From the structural viewpoint, the stabilization and coexistence of the tetragonal phases with different symmetries was obtained with Ta doping. The BNBK86Ta100α and BNBK88Ta100α ceramics morphology were affected by the Ta doping, being the average grain size decreased with increasing of the Ta content. In the comparative analysis of the dielectric and mechanical responses were identified the temperatures of three anomalies and phenomenologically described as: Td, related with the ferroelectric long-range ordering loss and the tetragonal to pseudocubic phase transition beginning; TRE associated with the paraelectric transition and Tm related to the maximum value of the real part of dielectric permittivity, where Td < TRE < Tm. A strong dependence of the height of Tm anomaly with Ta content was observed, being the Tm peak height reduced with the Ta increasing. From charge compensation mechanisms which occur with the Ta5+ ion substitution in BNBK ceramics, we conclude that the Ta doping reduces the oxygen vacancies concentration, give rise to experimental evidence which that Tm anomaly should be related with the interfacial polarization created by oxygen vacancies mobility. The ferroelectric properties of the Ta-doped ceramics showed that the Ta doping reduces the long-range ferroelectric ordering, resulting in the relaxor state stabilization at lower temperatures when compared with the pure BNBK system. On the other hand, the results of the energy storage densities showed an efficiency enhancement as a function of Ta content, resulting in exceptional values of the order of 90% with good thermal stability at high temperatures.
Estudo de propriedades estruturais, vibracionais, ópticas e magnéticas em amostras de Pb1-xCoxTiO3: transição de fase induzida por composição, temperatura e pressão
(Universidade Federal de São Carlos, 2019-03-29) Cunha, Thiago Rodrigues da; Pizani, Paulo Sérgio; https://lattes.cnpq.br/1038437165007849; https://lattes.cnpq.br/4748634662701381
This work presents a study of the synthesis and characterization of structural, vibrational, optical and magnetic properties of the compound Pb1-xCoxTiO3 (PCoT). The PCoT samples were synthesized using the Solid State Reaction method using a vibratory mill in the range of compositions at x ranging from pure PbTiO3 (PT, x = 0) to pure CoTiO3 (CoT, x = 1), (0 ≤ x ≤ 1), passing through the solid solution region, where the Co ions are diluted in the PT matrix (x < 0.1), advancing to the composite region, where the insertion of Co saturates the PT matrix and the CoT phase begins to form. These samples were initially characterized by Raman spectroscopy and x-ray diffraction (XRD) at ambient conditions (temperature and pressure) to determine the ideal conditions to synthesize each PCoT composition without spurious phase segregation, as well as to quantify the PT and CoT portions formed and analyze the effects of Pb-Co substitution on the structural and vibrational properties of these samples. Through Raman spectroscopy measurements as a function of temperature or pressure, it was possible to determine the influence of the composition on the PT (tetragonal to cubic) phase temperature (TC) or pressure (PC) transition, which presented a minimum of TC and PC at 720 K and 9 GPa, respectively, in the range of 0.3 ≤ x ≤ 0.5. Through XRD measurements as a function of pressure, it was possible to confirm the effect of the composition on the PC and to estimate the compressibility values and the bulk modulus (B0) for different PCoT compositions, so that B0, initially 103 GPa (x = 0), reduced to 84 GPa at x = 0.5, confirming an improve of compressibility induced by the Pb-Co substitution. Light absorption measurements in the UV-Vis region show that Pb-Co substitution reduces the optical gap of samples from 3.1 eV in the PT (x = 0) to 2.5 eV in the sample x = 0.1, while the CoT sample shows energy gap of 2.6 eV. The analysis of the magnetic properties through measurements of magnetic susceptibility as a function of temperature (χ × T) and measurements of magnetization as a function of the magnetic field (M × H), suggest that for low concentrations of Co (x < 0.1) there are a typical behavior of paramagnetic materials, while above x = 0.1 it is possible to observe the presence and establishment of the CoT phase formation due to the confirmation of the TN (38 K), typical of materials with antiferromagnetic order. Furthermore, at T = 5 K samples with composition x < 0.4 exhibit coercive field (HC) and remaining magnetization through M × H measurements, with 1500 Oe of HC, suggesting the presence of weak ferromagnetism at this temperature due to the possibility of interaction between Co ions diluted in the PT matrix.
Todo dia é um 7 x 1?: consagração e funcionamento da fórmula discursiva "complexo de vira-latas"
(Universidade Federal de São Carlos, 2019-03-29) Silva, João Thiago Monezi Paulino da; Salgado, Luciana Salazar; https://lattes.cnpq.br/5206927424265495; https://lattes.cnpq.br/1890557294738239
Esta tesis analiza, a partir de la circulación del sintagma “complejo de perros callejeros”, las discursividades constitutivas de los proyectos de nación/Estado instaurados durante el período entre las llamadas "Manifestações de junho" de 2013 y los Juegos Olímpicos realizados el 2016 en Brasil. Para ello, delimitamos, después de una amplia recolecta, un corpus de 48 textos, publicados en diferentes medios digitales (portales, redes sociales y blogs). Esta recolección se hizo a partir de la hipótesis de que este sintagma, de autoría de Nelson Rodrigues (en una crónica deportiva de 1958), se configuró como partícipe de un discurso constituyente (MAINGUENEAU, 2008 [2006]), y que se retoma con los rasgos de esa condición. En este sentido, se consideran aspectos semánticos constitutivos del proyecto estético-político que forma parte de la figura de autor de Nelson Rodrigues – elemento crucial en el establecimiento del sintagma como una fórmula discursiva (KRIEG-PLANQUE, 2010). De este modo, basada en el marco teórico del Análisis del Discurso francesa de base enunciativa y, más específicamente, con el enfoque teórico-metodológico sobre fórmulas discursivas, esta tesis verifica los aspectos que hacen del sintagma un referente social, una vez que, inscrito en una dimensión discursiva, asumió un carácter de material lingüístico cristalizado y pasó a comportar una disputa por sus sentidos, manteniendo un aspecto polémico. Con ello, se muestra el modo como, en el período recién mencionado, la circulación del sintagma “complejo de perro callejero” da indicios sobre la génesis de discursos acerca de un proyecto político-identitario de nación. Se perciben posicionamientos distintos a partir de la disputa por sentidos entre diferentes comunidades discursivas, sobre todo cuando se trata de las relaciones de Brasil con los países desarrollados. Se espera que esta investigación contribuya de forma más amplia a la comprensión sobre cómo la circulación y la difusión de determinadas unidades lingüísticas ponen en funcionamiento regímenes que definen posicionamientos discursivos de los sujetos. Por ejemplo: sentirse menos en relación al extranjero define un proyecto de nación.
Diversidade de inimigos naturais e redes de interações com vespas e abelhas solitárias
(Universidade Federal de São Carlos, 2019-03-29) Silva, Guilherme Gonzaga da; Ferreira, Rhainer Guillermo Nascimento; https://lattes.cnpq.br/2440863332849994; https://lattes.cnpq.br/6951142089667006
Natural enemies are one of the main regulating agents of populations. Among the natural enemies, those who adopt parasitism as strategy dominate the food webs. The hosts, on the other hand, have anti-parasitism strategies to escape the selective pressure that these natural enemies exert. Behavioral variation consists of a repertoire of individual choices that allow the body to respond quickly to the action of natural enemies. However, anthropogenic impacts have altered and even extinguished behavioral responses in many organisms. Habitat anthropization and landscape fragmentation consist of some of the major anthropogenic nowadays. Solitary wasps and bees have been used as models for biology and ecology studies because of easiness of collection with the trap-nests methodology. These hymenoptera also have potential as bioindicators of ecosystem status. Moreover, presenting great behavioral variety during nesting activity. However, few studies address the interactions of wasps and solitary bees with natural enemies and the factors that influence parasitism. Thus, the present study aimed to analyze the diversity of natural enemies and their networks of interactions with solitary hymenoptera that occur in a fragmented landscape composed of Cerrado fragments in restoration process, Eucalyptus plantation and riparian forest. In addition, we sought to identify which individual behavioral variations affect host parasitism rates. The areas presented similar diversity, with a significant difference only between Eucalyptus and riparian forest, which presented fewer species of natural enemies. The networks obtained were not nested and showed a greater tendency to generalist species in the silviculture area in relation to other predominant physiognomies in the study areas. The areas of Cerrado and riparian forest presented a higher index of specialization and modularity. The analyzes of factors influencing parasitism showed a nesting site effect, nest diameter and mean cell size only for Trypoxylon lactitarse. There was no correlation to Centris analis and Tetrapedia diversipes species. We conclude that human impact on landscapes may alter the diversity of natural enemies and limit their interactions with hosts. It is also concluded that differences in the biology of taxa make it difficult to identify the factors that affect parasitism in solitary bees.
Simulação computacional do início da precipitação induzida por deformação durante o processamento termomecânico de um aço microligado ao nióbio em resfriamento contínuo
(Universidade Federal de São Carlos, 2019-03-29) Souza, Antonio Lourenço Batista de; Balancin, Oscar; https://lattes.cnpq.br/8379205949387493; Canto, Rodrigo Bresciani; https://lattes.cnpq.br/1316268411830615; https://lattes.cnpq.br/3134592517806635
Improving the steel processing is a major focus of the metallurgical industry because the need of materials and products with lower weight and more strength, in addition to increasingly stringent specifications imposed by customers. The production of high strength low alloy steel, especially the higher cost ones, has only become possible with the understanding of the physical metallurgy of industrial processing. The knowledge and kinetic control of the phenomena that occur during hot processing such as recrystallization, precipitation and grain growth are mandatory for the grain size refinement, which is one parameter that determines the properties of semi-finished products. Over the years, several ways have been followed to investigate the industrial processing. One can cite as examples the use of pilot plants, physical simulations, and numerical simulations. The study of hot forming assisted by computer simulation is well spread nowadays. The development of materials models trustful enough to reduce cost with prototypes and virtually explore an infinitude of possibilities and thermomechanical loads is of interest of the metallurgical industry. The objective of this study was, therefore, to model the microstructural evolution and thermomechanical behavior of a niobium microalloyed steel during hot forming process, enabling the analysis of how the process parameters such as temperature, strain, strain rate influence the evolution of softening, precipitation and grain size mechanism during processing, using the commercial software DEFORMTM3D developed for forming processes analysis with the aid of subroutines in FORTRAN. The main results of this thesis were not only determining and understanding the plastic and microstructural gradients generated by thermomechanical processing, but also the construction of finite element model that might be useful to others researchers on the investigation of the thermomechanical behavior of new microalloyed steels in the processing products with complex geometry.