Navegando por Assunto "Energia"

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Acesso aberto (Open Access)
Ensino de ciências: uma proposta formativa para futuros professores dos anos escolares iniciais no estudo de energia
(Universidade Federal do Pará, 2022-06-09) HIRAI, Lêda Yumi; Fraiha-Martins, France; http://lattes.cnpq.br/4765567823575996; https://orcid.org/0000-0001-7933-6014
This is qualitative research in the narrative modality, based on the initial training of students of the Integrated Degree in Sciences, Mathematics and Languages for the Initial Years of Elementary Education, at the Federal University of Pará. Objective to understand the training processes experienced by future teachers in the early years when participating in a practice based on hybrid teaching, especially on the theme Energy in the rotation model by stations, in order to elaborate a proposal for the initial training of teachers to teach science in the early years. For the development of the analyzes and results, the field diary was used, the audio recording material made during the empirical research, as well as the material produced by the students in the tasks performed. And as a method of analysis, Discursive Textual Analysis was selected to understand the investigated narratives. In general, the undergraduates were interested in the practice, they had not had contact with the methodology of rotation by stations. The activities promoted reflections on the arrangement of tasks within each station, the contents and how the teacher's posture should be as a mediator of knowledge, guiding and guiding students towards knowledge. Through the results, the educational product entitled “ENERGY IN SCIENCE TEACHING: teaching practice of Station Rotation with students in the early school years” was created, considering its use by future teachers in the early school years to teach the energy theme. The material produced has three (03) units with information on the preparation of the activities script, suggestions of materials and technological tools to be used, I also present the planning of each station, containing lesson plans. In view of the training processes that were experienced by undergraduate students of the Integrated Licentiate course, I believe that the training proposal was accepted satisfactorily, being evidenced in the narratives of the undergraduates, when they point out their reflections on the theme and the material developed.
Acesso aberto (Open Access)
Estudo da viabilidade econômica para a utilização da semente da euterpe oleracea mart. (açaí) como recurso energético
(Universidade Federal do Pará, 2008-07-09) LUCZYNSKI, Miroslawa; MACHADO, Luiza Carla Girard Teixeira; http://lattes.cnpq.br/9773700229115395
This work had as objective the study of the economic viability for the Euterpe oleraceas Mart. (açaí) seed use as energy resource in the city of Belém-PA. Initially, it was realized a field survey of the sail points and quarters of biggest production of açaí, carrying through after that the assays of the termogravimetric properties of the seeds that are: Humidity text, volatile text, cinzas text, fixed carbon text and superior calorific power. The survey points made possible the creation of a data base, using the Microsoft Software Access, which supplies reports with the identification of the proprietors name, as well as the number of bags that is it processes per day, weight of bag and its energy potential. It was used still the Microsoft ARC VIEW, of easy interaction with Access that made possible the creation of an up to date map of the points for the city of Belém-PA. With those data a study of the transport routes was made in the Geographic Information System (GIS) GOOGLE EARTH. There were determined routes, through the Centroid method, which is the point of highest concentration of the variable of study, in this case, the açaís seed, for the transport of biomass to its final destination that is the UFPA, where if it finds the plant that uses the biomass as combustible to generate energy. When calculating the economic viability there were used the plant of Energy and Biomass of the Group of Energy, Biomass and Environment (EBMAs) together with the data of the consumption of electric energy of the UFPA in the period from 06/2006 to 06/2007, finally it was realized a comparison between the values gotten in the two done surveys and the confirmation of how much the UFPA would save in financial and energy terms with the biomass energy use. In conclusion the açaís seed is economically viable as energy resource for energy supply in UFPA, since the cost of supplied electric energy the concessionaire services the CELPA must exceed the cost of the renewable generation system, thus causing an economy in the final value, of the consumption of electric energy.
Acesso aberto (Open Access)
A física nos anos iniciais: obstáculos verbais em livros didáticos em uma perspectiva bachelardiana
(Universidade Federal do Pará, 2017-06-08) PEREIRA, Jefferson Rodrigues; Vieira, Eduardo de Paiva Pontes; http://lattes.cnpq.br/2902323640527915; https://orcid.org/0000-0003-1641-7014
The epistemological obstacles listed by Gaston Bachelard are configured as obstacles to scientific knowledge and are necessary to overcome such obstacles to the formation of the scientific spirit. Thus, this research aims to analyze energy concepts in textbooks from the early years of elementary school through the idealization of verbal obstacle in the perceptual bachelardiana. For this, we use elements of the content analysis, directed to the empirical material constituted by didactic books of sciences produced for the initial years. The analytical questions are confined to the didactic book because this is an important pedagogical instrument, pertaining to the daily life of the classroom, that can to some extent be considered a historical product; Thus producing idealizations and meanings. In this perspective, didactic books present situations in which words and the manner in which they are posed allow for the emergence of verbal epistemological obstacles. Among the various subjects that the textbooks discuss, the discussions related to energy are among the most significant to science education, mainly because of its unifying character. The tendency to use the term energy in different areas makes it difficult to distinguish "everyday energy" and "scientific concept of energy" because scientific conceptualization is treated after the use of the word, so it is not surprising that the scientific concept Is so complex. In this way, the difficulty with what is energy sustains the verbal obstacle that the term expresses, specifically, with justified reasons in the analysis of textbooks that demonstrate words or schemes that send energy to work, consumption, generation, transportation, which Substantializes or materializes energy and can be considered as idealizations of the verbal epistemological obstacle.
Acesso aberto (Open Access)
Geração de energia elétrica a partir dos resíduos do processo de beneficiamento do óleo de palma: uma abordagem sustentável para a recuperação de áreas degradadas no Estado do Pará
(Universidade Federal do Pará, 2017-01-16) KÜHL, Ricardo Marino; ROCHA, Brigida Ramati Pereira da; http://lattes.cnpq.br/9943372249006341
The deforestation, mainly verified in the Amazon region, has declined, but deforested areas, due to anthropic actions such as agriculture, or pastures opening, are still a hindrance, since the resilience process requires time to act. In this bias, the Agroecological Zoning, Production and Management of Oil Palm Culture in Amazon (ZAE-Dendê), evaluated the degraded areas in the Legal Amazon, aiming the palm plantation to recover them, based on the best practices. The present work goes beyond, evaluating the implantation of palm oil as a way of recovering degraded areas in Pará; the power generation from palm oil processing residues; as well as analyzing carbon dioxide reducing potential. The methodology used, covered the selection of degraded areas in Pará as the study area. Based on theoretical references some data were consolidate: the production of fresh fruits bunches (FFB) per hectare, the amount of waste per tonne of FFB, power generated from the residues and CO2 value fixation and emission. The results related to the CO2 emissions and fixation showed that the palm oil culture has the potential to reduce a range from 180 to 500 million tons of CO2eq., in addition to avoiding emission of 550 to 2,204 million tons of CO2eq., in a production cycle (25 years). The power generation potential verified from the anaerobic digestion of the liquid effluent range from 212 to 531 TWh during a palm oil production cycle. These data attests palm oil residues to become an alternative energy resource, as well as an alternative to degraded areas recovery. Therefore, this work is a subsidy for an Integrated Resource Planning elaboration.
Acesso aberto (Open Access)
Modelo de gerenciamento de usos múltiplos da água: um estudo de caso para a bacia hidrográfica do rio Tapajós
(Universidade Federal do Pará, 2016-02) FIGUEIREDO, Nelio Moura de; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
This work deals with a model for management of multiple uses of water, for the mitigation of conflicts of use related to the operation of reservoir systems in hydroelectric power plant of water catchment area. The model SOUMA – "system optimization of multiple uses of water", which consists of a stochastic optimization model based on nonlinear programming, was developed and structured in GAMS (General Algebraic Modeling System) with the use of solver MINOS. The SOUMA is composed of two modules. The first is a module for forecasting of water levels, which consists of a stochastic model of type ARIMA (Auto Regressive Integrated Moving Average). The second is a module for forecasting of streamflow, which is a stochastic model of rainfall-streamflow the RNA type. The ARIMA model calibration and validation presented average R² above 0.93 and RMSE below 0.08, capturing in a satisfactory manner the behavior of water levels. The rain-flow model that was used in the composition of influent flow to the reservoir, with the use of RNA architecture, presented average R² 0.954 and of 0.098 RMSE. The SOUMA model was applied to Tapajós River basin for the future hydroelectric power plant of São Luiz do Tapajós, Itaituba, PA. Six scenarios were created to be used as parameters in optimizing and mitigation of conflicts. The reservoir tributaries streamflow were obtained and simulated for dry, medium and moist hydrological scenarios and for El Niño, La Niña and Neutral climatic scenarios. For the power generation and navigation depth uses, considering the tributaries streamflow of the dry, medium and moist hydrological scenarios, the SOUMA showed, in relation to the reference levels of the low, medium and high navigation scenarios, the occurrence of depths below the minimum, for generations averages below 2,411 MW, 2,939 MW and 3,586 MW, respectively. For power generation and cargo capacity, considering the tributaries streamflow of the dry, medium and moist hydrological scenarios, the SOUMA showed, in relation to the low, medium and high reference levels of the navigation scenarios, that generations averages above 2,869 MW, 3,508 MW and 4,740 MW, respectively, do not generate earnings of cargo capacity and that medium generations below 1,344 MW, 2,056 MW and 1,622 MW, respectively, make the river transport of cargo infeasible. For power generation and flood dimension, considering the tributaries streamflow of the dry, medium and moist hydrological scenarios, the SOUMA showed, in relation the reference levels low, medium and high of the flood control, the occurrence of floods downstream to generations above average 4,978 MW, 6,057 MW and 7,390 MW, respectively. Consumptive withdrawals are meaningful only in the period from June to October. Considering the monthly average consumptive demands (145 m ³/s), to tributaries streamflow of the dry, medium and moist hydrological scenarios, the SOUMA showed a monthly loss in power generation of 50 MW, 47 MW and 44 MW, respectively. The measured results show that the models developed are important tools to operational optimization of reservoir systems with multiple uses, allowing the optimization of generations and defluente flow in the hydroelectric power plant of water catchment area, in periods of flood and drought and large energy demands, with maintenance of navigation conditions downstream from dams, through sustainable operational simulations that minimize usage conflicts.
Acesso aberto (Open Access)
Numerical Study of Wake Characteristics in a Horizontal-Axis Hydrokinetic Turbine
(Universidade Federal do Pará, 2016-12) SILVA, Paulo Augusto Strobel de Freitas e; OLIVEIRA, Taygoara Felamingo de; BRASIL JUNIOR, Antonio Cesar Pinho; VAZ, Jerson Rogério Pinheiro
Over the years most studies on wake characteristics have been devoted to wind turbines, while few works are related to hydrokinetic turbines. Among studies applied to rivers, depth and width are important parameters for a suitable design. In this work, a numerical study of the wake in a horizontal-axis hydrokinetic turbine is performed, where the main objective is an investigation on the wake structure, which can be a constraining factor in rivers. The present paper uses the Reynolds Averaged Navier Stokes (RANS) flow simulation technique, in which the Shear-Stress Transport (SST) turbulent model is considered, in order to simulate a free hydrokinetic runner in a typical river flow. The NREL-PHASE VI wind turbine was used to validate the numerical approach. Simulations for a 3-bladed axial hydrokinetic turbine with 10 m diameter were carried out, depicting the expanded helical behavior of the wake. The axial velocity, in this case, is fully recovered at 12 diameters downstream in the wake. The results are compared with others available in the literature and also a study of the turbulence kinetic energy and mean axial velocity is presented so as to assess the influence of proximity of river surface from rotor in the wake geometry. Hence, even for a single turbine facility it is still necessary to consider the propagation of the wake over the spatial domain.
Acesso aberto (Open Access)
Propriedades Térmicas do (Bio)Butanol e a Fotocatálise do Grafeno com Trifenilamina Dopado com Metais para Geração de H2
(Universidade Federal do Pará, 2019-01-10) MARTINS, Marcelo Gonçalves; CHAVES NETO, Antonio Maia de Jesus; http://lattes.cnpq.br/3507474637884699
In this study, the optical properties and electronic structures of the transition metal-doped G-TPA using water as solvent were theoretically investigated in order to evaluate the efficiency in the production of photocatalytic hydrogen. in the Gaussian 09W software, using the B3LYP functional for all structures, and the base 6-31g (d) for the H, C and N atoms, and the LANL2DZ base, applying the effective potentials method for the transition metals (Ni, Pt, Pd, Fe, Os). Through the DOS of each structure an increase of accessible states in the valence layer was observed, as well as the decrease of the gap for all doping and for the structure with two and three radicals of triphenylamine. Through the UV-vis absorption spectrum, there was an improvement in absorption in the range of 490 nm to 615 nm. Another analysis carried out in the sense of energy generation was the evaluation of the thermodynamic potential of the butanol properties as complementary fuel or substitute for conventional fuels. For this, the Gaussian09W allied to the DFT was used again, but combined with the functional ones, hybrid B3LYP with the base set 6-311 ++ G (d, p) and 6-31 + G (d), G3 and G4 , in addition to the CBS / QB3 compounds. The simulations were carried out and the thermodynamic properties were found, such as: the specific molar heat at constant pressure, the enthalpy of formation and the entropy. All the properties were obtained between the temperatures 100K - 1500K and constant pressure of 1atm, in addition the enthalpies of combustion of the butanol isomers were obtained, several ternary mixtures were also proposed where it was possible to compare the enthalpy variations between the fuels: gasoline, ethanol and n-butanol.
Acesso aberto (Open Access)
Reliable Energy-Efficient Multilayer Mechanism with Realistic Battery Model and QoE Support in Wireless MANETs
(Universidade Federal do Pará, 2016-03) CARVALHO, Tássio Costa de; FERREIRA JUNIOR, José Jailton Henrique; FRANCÊS, Carlos Renato Lisboa
Evolution in the telecommunications networks and the rapid advances made in wireless mobile communication networks, have taken computer networks to a new communication level. They now provide support for new mobile multimedia applications and are thus fostering the development of new network types and configurations. MANET is an important configuration of network for operations that employ mechanisms to enable dynamic self-configuration, self-optimization and self-healing, which is a challenging task for the routing protocols, new multimedia application and the battery energy consumption of wireless and mobile devices. These protocols are challenging because battery problems are more serious in this type of network and the existing protocols are not adapted to current problems, particularly mobile multimedia streaming, that can be found in most Internet flow. This paper proposes a reliable energy-efficient multilayer mechanism to address this to make improvements in the main current protocols. The proposal adds decision metrics to an energy-efficient computational intelligence technique based on Fuzzy-System with QoE, mobility and battery guarantees, choosing the best path in an efficient and accuracy way. The proposal has been evaluated in a network simulator.
Acesso aberto (Open Access)
Trocas turbulentas noturnas de CO2 entre a floresta de Uatumã, Amazonas, e a atmosfera
(Universidade Federal do Pará, 2014-07-04) MAFRA, Ana Carolina Batista; SÁ, Leonardo Deane de Abreu; lattes.cnpq.br/0107976161469463; ARAÚJO, Alessandro Carioca de; lattes.cnpq.br/6188087583954899
We study the nocturnal boundary layer - NBL above an area of primary tropical forest northeast of the state of Amazonas, the Sustainable Development Reserve of Uatumã, distant 15 km of the Uatumã River, located about 380 km northeast of the city of Manaus, Amazonas. It is intended to determine some of the characteristics of the NBL, particularly nocturnal turbulence regimes by identifying the differences related to vertical exchanges of CO2, according to the methodology proposed by Sun et al. (2012). Fast response data will be used for the atmospheric scalar and vector quantities, as CO2 concentration and wind speed, respectively. The methodology allows characterization of NBL in three regimes of dynamic stability: 1) weak turbulence, mean low wind speed; 2) strong turbulence, with high wind speed, and 3) intermittent turbulence events with "top -down ". From this characterization, we have investigated some of the main statistical characteristics of each turbulent regime. As would be expected, the turbulent fluxes of CO2 increases with the characteristic scale of turbulent velocity, VTKE, associated with turbulent kinetic energy measured above the forest canopy. The CO2 exchange increases considerably with the regime 2,with higher values of the mean wind speed, | V |, and with the occurrence of strong mixing in the atmospheric boundary layer, ABL, not predominantly generated by surface forcings .