Navegando por Data de Publicação, começando com "2021-03-03"

Filtrar resultados por ano ou mês

Agora exibindo 1 - 6 de 6

Análise de textos por meio de processos estocásticos na representação word2vec
(Universidade Federal de São Carlos, 2021-03-03) Massoni, Gabriela; Stern, Rafael Bassi; https://lattes.cnpq.br/7846211197320014; https://lattes.cnpq.br/0694571733841497
Within the field of Natural Language Processing (NLP), the word2vec model has been extensively explored in the field of vector representation of words. It is a neural network that is based on the hypothesis that similar words have similar contexts. In the literature in general, the text is represented by the mean vector of the representations of its words, which, in turn, is used as an explanatory variable in predictive models. An alternative is, in addition to averages, to use other measures, such as standard deviation and position measures. However, the use of these measures assumes the order of the words does not matter. Thus, in this dissertation we explore the use of stochastic processes, in particular, Time Series Models and Hidden Markov Models (HMM), to incorporate the "chronological" order of words in the construction of explanatory variables from the vector representation given by word2vec. The impact of this approach is measured with the quality of the predictive models of real data and compared to the usual ones. For the analysed data, the proposed approaches have a result that is superior to or equivalent to the usual approaches in most cases.
Energia de biomassa como uma perspectiva para o problema energético e ambiental de São Tomé e Príncipe
(Universidade Federal de São Carlos, 2021-03-03) Apresentação, Marcos de Jesus Fonseca de; Silva, Diogo Aparecido Lopes; https://lattes.cnpq.br/1101747760784249; Yamaji, Fábio Minoru; https://lattes.cnpq.br/4787449634914831; https://lattes.cnpq.br/7574353788654033
Among renewable energies, bioenergy is the one with the greatest participation in the global energy mix, corroborating with the various studies carried out in the area. Today, in the scopus search string alone, there are about 31,000 scientific articles in the field. To analyze the large amount of literature in the area, the method of systematic bibliographic review (RBS) was used. The objective of the first article was to understand the bioenergy scenario, answering the 4 questions: What is the bioenergy scenario in the World and in Africa; What are the main cultures used; Which harness technologies are being employed; What are the main benefits and implications that its use brings. For this, the model proposed by Conforto et al. (2011). The results show that, since the year 2000, bioenergy has been promoted as an alternative source of energy and has become part of the policy, which has led to the continuous growth of research. Currently, research around the world is focused on carbon dioxide capture and storage bioenergy (BECCS) and scenario analysis. As for the African continent, although the government is interested in modern bioenergy and in the implementation of several projects related to bioenergy, traditional biomass is still the main source of energy. The cause of this problem is the lack of clear policies and coordination with researchers. Regarding the third question, the most used raw materials are: waste, forest, wood, sugar cane, seaweed, jatobá, oil palm, grass, corn, coal, miscanthus. The use of these raw materials for bioenergy brings many benefits, such as: gender equality, reduction of social inequality, improvement of living conditions, income generation, sustainable economic development, reduction of deforestation, reduction of air pollution and better destination of these waste. Pondering these benefits, the objective of the second article was to analyze the bioenergetic potential of the main energy cultures of São Tomé and Príncipe and to point out some of the benefits that may arise from their use. For this calculation, the formula proposed by the Bioenergy Atlas of Brazil in 2012 was used, obtaining an energy potential of 4.5 GW / year, where 80% of this potential was from two cocoa and banana crops. Considering the potential of these two cultures, the third article proposed the manufacture of briquettes. For this, norms of ISO, NBR of ABNT were adapted, for the immediate analysis and for the other performed analyzes. It was found that it is possible to produce briquettes with these two cultures, without the use of binder and temperature. São Tomé and Príncipe can benefit greatly from bioenergy, increasing the share of renewable energy in its electrical matrix, decreasing the dependence on imported diesel, reducing losses indistribution by installing small decentralized systems and other benefits mentioned throughout this work.
Avaliação do efeito “priming” na qualidade do vermicomposto de Eichhornia crassipes
(Universidade Federal de São Carlos, 2021-03-03) Kotsubo, Karolina; Santino, Marcela Bianchessi da Cunha; https://lattes.cnpq.br/2356641063223397; https://lattes.cnpq.br/2944939744248135
In eutrophicated environments, aquatic macrophytes reproduce rapidly and occupy large areas, hindering the multiple uses of water resources. The use of the biomass of these plants in vermicomposting represents a sustainable alternative. The objective of this work consists in the evaluation of the vermicomposting using macrophyte biomass and the addition of organic and inorganic substances to this process. The hypothesis that motivated this study is that the enrichment by organic and inorganic substances increases the fertility of the produced compost and the consumption of the biomass by the annelids. The enrichment of macrophyte biomass during vermicomposting by inorganic NPK (1.75% and 3.5%) and organic glucose (0.25 g/L and 0.5 g/L) solutions was tested. Humidity and temperature did not prove to be limiting to the process, remaining within the standard for vermicomposting. The pH and the electrical conductivity also had an expected behavior for vermicomposting. The efficiency of biomass consumption of the treatments with NPK were 21.57% and 8.7% higher than the control. For the treatments with glucose, the efficiency was 51.5% and 40.5% higher than the control. Both treatments showed superior quality of the compost formed when compared to the control. Regarding humification, the enrichment with NPK was intermediate, with higher values of humic substances formed and higher humification indicated by the E2/E3 ratio. The enrichment with glucose showed higher nutritional potential due to higher biomass consumption efficiency, higher humification represented by the E4/E6 ratio, and higher fertility values for total organic matter, nitrogen, phosphorus, and calcium. The data confirmed the initial hypothesis that both organic and inorganic enrichment would improve the quality of the generated compost and biomass consumption. Glucose caused a positive effect to the compost formed, with increased fertility and vermicomposting efficiency, besides being low cost, easy to obtain and apply. Despite the improvement in the composts, they prove to be inadequate for full use as fertilizer, being suggested the combination with other fertilizers and favoring soil moisture and structuring.
Regionalização no contexto brasileiro de modelos de avaliação de impacto do ciclo de vida para a categoria de formação de material particulado
(Universidade Federal de São Carlos, 2021-03-03) Giusti, Gabriela; Tadano, Yara de Souza; https://lattes.cnpq.br/1411041491592598; Silva, Diogo Aparecido Lopes; https://lattes.cnpq.br/1101747760784249; https://lattes.cnpq.br/9571785847881246
Particulate matter (PM) is an air pollutant emitted by anthropic activities directly associated with human health's impacts. One way to estimate the environmental impacts of PM is through Life Cycle Assessment (LCA) studies, which through characterization models associate an elementary flow to an impact category using characterization factors (FCs). However, the main current models for estimating CFs in LCA do not fully address Brazil's heterogeneity. Thus, the main objective of this work was to develop a model recommendation and a partial regionalization of CFs for the PM formation category in Brazil's context. For this, the state of the art on the subject was studied with a systematic bibliographic review (SBR) of the literature, and the available characterization models were identified. The models were critically evaluated and the most suitable ones for application in Brazil were recommended based on the methodology of the Life Cycle Impact Assessment Network (RAICV) and multicriteria decision analysis. Subsequently, models that could be regionalized in the national context were identified, and the models by Fantke et al. (2017, 2019) were selected for the development of a partial regionalization by changing its calculation variables: urban, rural, and total population; urban and rural land area; precipitation, and; mortality due to health effects. As a result, the SBR collected 210 documents. The exploratory search identified 16 characterization models and the recommendation analysis indicated the models by Fantke et al. (2017), Fantke et al. (2019), UNEP and SETAC (2016), and Van Zelm et al. (2016) as the most suitable for application in Brazil. However, it was found that these would still need to be regionalized for better use in the national context. The partial regionalization of Fantke et al. (2017, 2019)’ models resulted in a significant percentage variation of the CFs values concerning the original data. In general, significant reductions in the new calculated and regionalized CFs were observed concerning the originals, leading to the conclusion that the original data of the model possibly generate an overestimation of the impacts associated with the emission of PM in Brazil. A case study evidenced this observation by showing a 50% reduction in the impact of damage to human health by forming PM in a Brazilian production system for wood panels production. It is concluded with the partial regionalization that the data currently available for Brazil, despite having an important territorial variability, still present uncertainties for the country and are available in an uneven way between the regions (only 126 municipalities of the 5,570 existing ones), being necessary continuity of the regionalization procedure for this category. Also, CFs for secondary PM with the same spatial quality and easy access at the level of cities and archetypes are still a demand in the area, less explored in the literature. It is therefore recommended that future studies aim to continue this regionalization of CFs for the formation of PM in the country.
Comportamento coordenado e individual em duplas de ratos sob esquema de intervalo variável
(Universidade Federal de São Carlos, 2021-03-03) Santos, Letícia dos; Souza, Deisy das Graças de; https://lattes.cnpq.br/4404800720856419; https://lattes.cnpq.br/8469573182798669
The combined behavior of two or more individuals is subject to selection by the consequences of the environment, in the same way as individual operant behavior. Previous studies used an interdependence procedure to investigate the response- reinforcement relationship and the effects of the type of reinforcement schedule on coordinated behavior. One of the studies investigated the effects of parametric manipulation in a fixed-ratio schedule (FR 1, 6, 12, 18, 24, 30, 50, and 70), on the performance of pairs of rats, under two conditions, one that required temporally coordinated responses of the two members of each pair, and another in which the reinforcer was delivered for independent individual responses (Coordinated versus Individual Condition). The results obtained showed that the function that relates the total rate of responses to the size of the reinforcement ratio had an inverted U shape, both for coordinated responses and for the responses of rats that worked individually, replicating the function obtained with individual organisms in previous studies. The coordinated response patterns also replicated those obtained with individual organisms: the higher the ratio of the schedule, the higher was post-reinforcement pauses. Considering researches on coordinated responses and reinforcement schedules, the present study aimed to investigate coordinated behavior as a function of parameters of variable-interval schedules (VI), that generates different patterns from the FR schedules, aiming to increase the understanding of selection processes of coordinated responses among rats. Planned as a systematic replication, where the main variable now is the rate of reinforcement and its variable distribution, the study explored the VI 5, 10 s, 20 s, 40 s, and 80 s intervals for a condition with no coordination requirement among rats, and the VI 5 s, 10 s, 20 s, 40 s, 60 s, 80 s, 120 s, 160 s and 320 s for a condition with a coordination requirement among the pairs, which were compared to each other. Six pairs of rats were used, three pairs for each condition. The results obtained indicated a bitonic function, in an inverted U shape, which relates response rate and reinforcement rate, replicating data from the extensive literature on the VI schedule for individual responses. This function was observed in the global response rates for the Coordinated Condition and Individual Condition, in the rate of coordinated and “equivalent” responses to the coordinated responses, and in the percentage of coordinated responses in both conditions. In addition, it was observed that the contingency of the schedule that required coordination had a relevant role in the selection of the coordinated response among the pairs, generating higher rates and percentages of coordinated responses when compared to the data of the subjects exposed to the individual schedule. The results extend the research line that has been investigating coordinated responses patterns under intermittent schedules of reinforcement.
Evolução de fases durante a hidratação do cimento portland brasileiro por difração de raios x
(Universidade Federal de São Carlos, 2021-03-03) Gonçalves, Beatriz; Ishikawa, Tomaz Toshimi; https://lattes.cnpq.br/5726055117451807; Koga, Guilherme Yuuki; https://lattes.cnpq.br/0933095081175012; https://lattes.cnpq.br/9604476160326770
The physicochemical properties of cementitious materials are determined by the mineralogy and hydration process of the cement. In 2018, the ABNT NBR 16697 standard was published, unifying eight standards related to Portland cement. The main changes occurred in the composition, with the increase of the permitted content of the additions. The increase of the addition content in the cement indicated the need of a better understanding of its mineralogy and phase evolution upon hydration. The project aims to understand phases evolution during the hydration of two commercial Portland cements (CP II-F 40) using XRD, focusing on the in situ technique, which had the results compared with the conventional ex situ technique. To understand phases development during hydration, the following methodology were adopted: powdered cements characterization (anhydrous), cementitious pastes characterization with different hydration ages (from 15 minutes to 28 days), in situ and ex situ characterization of the phases progress within hydration. Complementary standardized thermogravimetry analysis (TGA) and compression tests were performed, and the results related to the evolution of phases. The cement with higher alite and aluminate levels showed faster C-S-H and portlandite phase development and more pronounced formation of AFm phases. The ex situ XRD made it possible to quantify the contents of each constituent over time, including amorphous content, and proved to be effective in identifying aluminate hydrates that can affect the performance of CP II-F cements. The in situ method offers time savings, but it is still necessary to develop more accessible approaches for rapid quantification.