Programa de Pós-Graduação em Engenharia de Infraestrutura e Desenvolvimento Energético - PPGINDE/NDAE/Tucuruí

URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/9400

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Acesso aberto (Open Access)
Análise da viabilidade técnico-econômica da geração de energia solar fotovoltaica em unidades de confinamento bovino com sombreamento artificial
(Universidade Federal do Pará, 2020-05-28) MORAES, Emerson Ricardo de; MOURÃO, Raphael de Castro; http://lattes.cnpq.br/6637481796428177; ISHIHARA, Júnior Hiroyuki; http://lattes.cnpq.br/3498874642887006; https://orcid.org/0000-0002-0081-7913
The increase in worldwide population caused a rising search by food, both origins, vegetable and animal. Due the decrease in rural areas to destined for livestock activities, as a result to greater use of areas for agriculture, there are an intensification in cattle farming, the aim to use a smallest area of property for a large quantities of animals, at same time, associated the animal welfare and its thermal comfort, and provide improvement in production system. This population increase also implicate in higher demand for electric energy sources, due to the improvement of living standards and advances technologic. The objective this work was to analyze the technical and economic viability of the generation of solar photovoltaic energy, in line the livestock activity, using the shading sheds coverage in beef cattle feedlot. A bibliographic study was carried out on the animal yield of the Nellore breed, in confinement in a tropical climate, in the situation of total exposure to the sun or with the use of shady sheds. Three scenarios were created for the analysis of animal welfare, the animal being confined in the open, confinement with the use of shading sheds and confinement with the generation of solar photovoltaic energy on the roof of its shading shed. Two alternative meteorological stations were made to collected the samples of local climatic variables, and calculate the indices of thermal comfort and animal well-being, and to identify the possible beef cattle yield at the study site. Budgets for items and services were made for the execution of projects for containment pens, roof sheds and distributed generation of photovoltaic solar energy, for further analysis of the technical and economic feasibility of the projects. The results showed greater economic viability, with greater profitability and shorter return on investment, for the treatments of confinement pens in the open, which present, for the population of 200, 600 and 1000 animals, an IRR of 75.86%, 86.71% and 89.88%, PI of 4.68, 5.34 and 5.53 and discounted payback of 1.49, 1.29 and 1.24 years, respectively, while for the construction of the entire structure together with the generation of solar photovoltaic energy, it was obtained, in the same order, IRR of 22.30%, 14.09% and 14.62%, PI of 1.58, 1.18 and 1.21 and discounted payback of 5.17, 7.71 and 7.48 years. Although the economic feasibility was not the best, treatments with a photovoltaic energy generation system connected to the distribution network, when built together with the structures of confinement and shed pens, provide greater comfort to the animals and enable the generation of energy renewable. The result of the photovoltaic installation was more economically viable, when mounted on shed structures already existing in confinement systems for 200 animals, which presented an IRR of 23.72%, PI of 1.65 and a discounted payback of 4.88 years. It is concluded that the most viable design option for the creation of animals in feedlot, is the open model for the largest number of animals, while for the generation of energy, it is the system connected to the low voltage network mounted on shed structures already in feedlot systems for 200 animals, without the need for demand contracts, containing 200 photovoltaic panels.
Acesso aberto (Open Access)
Análise da viabilidade técnico-econômica de implantação de reciclagem de pneus para produção de CBUQ em Tucuruí
(Universidade Federal do Pará, 2019-02-21) MOUSINHO, Mateus Mamede; MESQUITA, André Luiz Amarante; http://lattes.cnpq.br/1331279630816662
Population growth and rapid technological development have contributed to increased solid waste generation by improperly disposing of post-consumer tires, which are not biodegradable and their decomposition time is not yet precisely determined. To be defended that the recycling culture does not only show aspects of environmental and educational preservation, it is also necessary to justify recycling as an economic activity that generates employment and income to the city, contributing to the well-being and quality of life. Therefore, the main objective of this research was to quantify the discard of waste tires and to analyze the technical-economical feasibility for the implementation of the recycling process of waste tires in the production of rubber aggregate in the asphalt mixture at the city's asphalt plant. To do so, it was measured the disposal of waste tires in a given period in Tucuruí and estimated the disposal volume of the adjacent cities, in addition, it was analyzed the operational activities and production costs of the waste as a rubber aggregate. In the field survey, 98 questionnaires were applied in 30 neighborhoods where the establishments were in January 2018. Thus, there was a monthly amount of 1,664 tires in the rubber workshops, 2,347 tires in the mechanical stores, totaling 4,011 tires in the municipality, which allows to conclude that the city presents a large volume of this solid residue. Adjacent cities presented in their estimate a total of 8,031 tires unserviceable per month. For the production of the rubber aggregate asphalt mixture, the conventional CBUQ trait was used in relation to the modified CBUQ developed by Coelho (2018), in which it was estimated that one kilometer of asphalt mixture of thickness of 3,5 centimeters can be used approximately 11.72 tonnes of recycled aggregate (8.79 tonnes of rubber and 2.93 tonnes of wood sawdust), this is equivalent to 1,465 car tires or 5,170 motorcycle tires, leading to an economy in the purchase of raw material from R$ 56,075.41 per kilometer. It is concluded that the results of the three scenarios are satisfactory, the simulations of the study were only the resources available to produce the rubber aggregate generated by the municipality as a pioneer project, with the intention that other municipalities are part of this visual identity of sustainable city.
Acesso aberto (Open Access)
Análise das propriedades tecnológicas da cinza do caroço de açaí na cerâmica vermelha
(Universidade Federal do Pará, 2019-09-16) FERREIRA, Taiana da Silva; SOUZA, Paulo Sérgio Lima; http://lattes.cnpq.br/4933212993218783; ISHIHARA, Júnior Hiroyuki; http://lattes.cnpq.br/3498874642887006; https://orcid.org/0000-0002-0081-7913
The raw materials from the exploration of deposits used for the manufacture of products used in construction and the environmental impacts caused by the red ceramic sector evolved as cities developed. The need for the use of alternative materials, such as waste biomass, has become increasingly necessary studies aimed at the reuse of waste in the process of production and manufacture of ceramic materials. Thus, this work has the objective of evaluating the incorporation of ash from the acai kernel residue (RCA) in the clay mass and to evaluate the technological properties of red ceramic. The materials were chemically and physically characterized, and then extruded specimens were molded using 0%, 10%, 15% and 20% RCA ash mixed in two types of clay, called red clay and dark clay. After firing at 950 ºC, the pieces were subjected to water absorption, apparent porosity, specific gravity, linear shrinkage and flexural strength stress tests. The results showed that the use of RCA ash contributed to the workability of the mixtures, reducing the need for additional water for molding. It was also verified that the 10% ash content as a partial substitute of red clay, and the mass containing 50% of red clay and 50% of dark clay, had a positive influence on the evaluated technological properties. However, for the 20% ash incorporation of RCA, the values were median and for the unsatisfactory porosity assay. Thus, it was possible to verify the technical feasibility of using açaí stone ash in partial substitutions, contributing to the reduction of raw material exploration, reduction of solid waste disposal and the reuse of the residual biomass of açaí stone in the production of ceramic materials.
Acesso aberto (Open Access)
Análise de atributos de classificação para o diagnóstico de falhas em rolamentos baseado em SVM
(Universidade Federal do Pará, 2019-08-06) SOUZA, Jusley da Silva; BAYMA, Rafael Suzuki; http://lattes.cnpq.br/6240525080111166; MESQUITA, Alexandre Luiz Amarante; http://lattes.cnpq.br/3605920981600245; https://orcid.org/0000-0001-5605-8381
In industries, the concern in total availability of machines and the mechanical equipment in the productive area it’s subject of research and tests to obtain more efficient techniques to be applied for monitoring and faults’ diagnosing. Bearings are machine elements of great application in the industrial area and they present high fault index that generate machine’s stops to carry out maintenance. For this reason, this paper presents Artificial Intelligence technique applied to the vibration signals of a rotary machine for fault diagnosis in its bearings. The vibration signals are part of an open database offered by Case Western Reserve University. In this paper the Support Vector Machine (SVM) classification algorithm is applied in two ways for the rolling bearings faults’ diagnosis. In the first case statistical predictors (Root Mean Square Value, Crest Factor, K Factor, Kurtosis and Skewness) are used as features for the SVM classifier. In the second case, the signal processing is performed by applying the Ensemble Empirical Mode Decomposition (EEMD), which generates several signals called Intrinsic Mode Functions (IMFs). For each IMF, it’s modeled using Autoregressive Modeling (AR), and the AR modeling coefficients of each IMF are used as features for the SVM classifier. The analyzes are performed for training and validation groups, with randomly chosen window and with temporal sequence chosen window, considering two classification problems within the same data, the first one considers the same severity and only changes the fault type and the other vary both severity and fault type. As result, both methodologies presented excellent reliability results for bearing faults’ diagnosis.
Acesso aberto (Open Access)
Análise de dano em barragens de concreto através do método dos elementos finitos
(Universidade Federal do Pará, 2019-08-30) BORGES NETO, Osvaldo Sousa; PRAZERES, Plínio Glauber Carvalho dos; http://lattes.cnpq.br/6175760351403329
The mechanics of damage in continuous mediums studies the effects of degradation, in diffuse and progressive way, suffered by solid bodies under requests of mechanical or non-mechanical nature. Therein such effects are taken into account by reducing the strength and stiffness properties of the damaging material. Materials such as concrete and rocks have as their basic reason for their nonlinear behavior, micro defects in their microstructure that favor the concentration of micro tensions. These micro defects constitute what is understood as the initial damage of the material. The purpose of this work is the study of appropriate damage models for the analysis of damage mechanisms in concrete dams. For this, a linear softening isotropic damage model was used and the damage model of Cervera et al. (1996) in the analysis of two sections of concrete dams. The model of Cervera et al. (1996) stood out for presenting good results in the identification of damage as well as better describing the real aspect of the stress versus strain curve of the concrete. To validate the results, the example of a wall beam by Proença et al. (2002) in which the damage results were compatible with that of the Matlab language program.
Acesso aberto (Open Access)
Análise do aproveitamento energético em redes de distribuição de água com a utilização de bombas como turbina (BFT)
(Universidade Federal do Pará, 2022-03-31) SILVA, Victor Renan Barbosa da; ISHIHARA, Júnior Hiroyuki; http://lattes.cnpq.br/3498874642887006; https://orcid.org/0000-0002-0081-7913
Climate change has intensified research related to the production of renewable energies around the world. In this sense, the present study intends to contribute to the analysis of the use of Pumps Functioning as Turbine (PAT) to replace Pressure Reducing Valves (PRV), aiming both at the control of pressure in water distribution networks, as well as , consequently, its use for energy generation. The installed PAT must be able to operate under different flow rates due to fluctuations in the water consumption rate, which makes it difficult to select the appropriate pump, therefore, the selection process of PATs to replace PRVs was optimized by combining two selection methods and PAT prediction, Williams (1995) the first method was used to select the appropriate PAT according to height and flow data available in the network, then the method of Rossi et al. (2019) was used to evaluate the characteristic curves of the pump as a turbine, with particular attention to out-of-design operating conditions. Two simulations were performed for the optimization process, considering the PAT with constant speed, applied to a real network that was divided into 3 district measurement areas (DMA). In the first simulation a PAT was added to the network to replace a PRV located at (DMA 3), in the second simulation two PATs were added to the network (DMA 3) to replace the PRVs. The results show, in simulation 2, that the pressure control was better, in addition to the recovery of electrical energy, which was 190.96 kWh/day or 69.70 MWh/year, corresponding to a reduction of 41.74 tons of CO2 not emitted. Thus, the energy recovery was 267% higher compared to simulation 1. In addition, the pressure control also presented satisfactory results, staying within the established standards. Therefore, the combination of Williams' (1995) and Rossi et al. (2019), simplified the work of BFT selection and prediction with significant results and it was possible to conclude that BFTs working at peak consumption hours can adjust the required standard pressure and, in the rest, PRVs can regulate the pressure. In this case, in addition to controlling the pressure continuously, significant renewable energy can be recovered from the WDN
Acesso aberto (Open Access)
Análise do ciclo de vida da cadeia da banana na região do Lago de Tucuruí
(Universidade Federal do Pará, 2018-07-20) PINHEIRO, Joana Cláudia Zandonadi; MESQUITA, Andre Luiz Amarante; http://lattes.cnpq.br/1331279630816662; GOMES, Luiz Moreira; http://lattes.cnpq.br/7074266533007983
This work deals with the analysis of the banana life cycle in the Lake of Tucuruí region, in the State of Pará. The environmental impacts of this product and its production chain are quantified. It is also evaluated the potential of beneficiation, aiming the incentive of its production in the region. Regional banana producers were visited on their properties, where they mapped the life-cycle flows of this product, from planting to sale. The methodology applied in the research involves the Life Cycle Analysis (LCA) tool, which allows the visualization of the environmental and economic contributions of each productive process. This approach makes it possible to focus analysis on reducing environmental impacts and on better processing practices and costs of product processing. The obtained results show that the properties studied have similar emission indices of environmental impacts as others studied in the world and that the stages of the planting until the formation of the fruit have elevated indices of emissions, so that the application of best practices to the processes, so that there is potential reduction of the environmental impacts generated. The LCA methodology used was extremely important to identify the factors that impact the problems of agricultural production. Thus, we can propose improvements in the use of natural resources for the properties studied, seeking conservation and sustainability for future generations.
Acesso aberto (Open Access)
Análise experimental da eficiência de bielas de concreto simples e armado em modelos locais e globais
(Universidade Federal do Pará, 2019-03-21) FREIRE, Marília Caires; FERREIRA, Maurício de Pina; http://lattes.cnpq.br/4242041552985485; https://orcid.org/0000-0001-8905-9479
Reinforced concrete beams are usually designed by sectional analysis methods, where Bernoulli hypothesis is taken into account, assuming that strains are linearly distributed along the cross-sectional area of the element. However, many practical situations require distinct calculation alternatives, made by both fundamentally empirical code expressions and numerical or analytical solutions from the Strut-and-Tie Method. This is the case of deep beams, where a bottle-shaped strut is formed and the influence of its reinforcement ratio is generally discounted by the current design codes. Therefore, an experimental study was performed to assess the efficiency of plain and reinforced concrete struts, by local and global models, respectively represented by diamond-shape panels loaded in small bearing areas and deep beams, since in both the resistant mechanism seems to be directly related to the flow of stresses in the concrete strut. The results showed similar behaviors among the models regarding strains in concrete and reinforcement, as well as equivalent failure modes resulting from a splitting crack of the strut. With the increase of transverse reinforcement ratio, gains of ultimate strength, ductility and cracking control were observed, mainly for specimens with mesh reinforcement, as well as higher and safe results for the analysis by the strut efficiency factors. On the other hand, the assessment of shear strength by the design codes showed unconservative predictions with increasing transverse reinforcement. This way, it is confirmed that solutions by strut-and-tie models are more suitable methods for the efficient and safe design of structures with regions of disturbance in the stress-strain distribution.
Acesso aberto (Open Access)
Análise experimental do cisalhamento em vigas de concreto armado reforçado com microfibras
(Universidade Federal do Pará, 2019-01-31) OLIVEIRA, Mateus Gonçalves de; TEIXEIRA, Marcelo Rassy; http://lattes.cnpq.br/8912916360456192
The shear study for small, medium and large works, the latter known as works of art, with the use of reinforced or prestressed concrete presents particularities in the definitions of the traces, since, it has the need to minimize the propagation of fissures, as well as to obtain suitable mixtures considering the high characteristic high diameter of the large aggregates, as well as to avoid deleterious reactions in the concrete. In this sense, the main objective of this research is to analyze the shear behavior of reinforced concrete beams, with reinforcement of glass and polyester microfibers for each type of cited in volumetric fractions (0,024%, 0,032% e 0,048%), comparing them with the behavior of fiber- aiming its application in structural elements. In order to meet the proposal of this research, the methodology was based primarily on the characterization of concrete constituent materials (cement, small and large aggregates and fibers already mentioned), concrete dosage based on the Concrete Dosage method EPUSP -IPT, concrete of the beams, being: one of reference without fiber addition and 6 (six) with additions of microfiber of glass and polyester, being three (three) for each one of them, and later analysis as to shear through the breaking of the experimental beams, and computational analysis between the beam modeled in the Response 200 software considering stirrups throughout its section and the experimental reference without stirrups in 1/3 of its sections. It can be stated that the glass and polyester microfibers have shown that their uses can be used as partial replacement of the transverse reinforcement; contributed to post-peak or post-cracking stability; contributed to the gain in shear strength of 15.1% for VFV01 (beam with addition of glass microfibers with a percentage of 0.024%) and 21.6% of VFP02 (beam with addition of polyester microfiber with a percentage of 0.032%) both in relation to VR (reference beam). Therefore, this study demonstrated that the fibrous reinforcement can be used as control efficiency and as well as shear performance improvement in structural concrete.
Acesso aberto (Open Access)
Análise experimental dos limites superiores de resistência à punção de lajes lisas de concreto armado com armaduras de cisalhamento
(Universidade Federal do Pará, 2018-10-30) FREITAS, Marcus Vinícius Pereira de; FERREIRA, Maurício de Pina; http://lattes.cnpq.br/4242041552985485; https://orcid.org/0000-0001-8905-9479
In the flat slab system, the slab-column connection is a critical point due to the risk of punching shear failure. Several structural collapses are reported due to this mode of failure and constructive errors are the main causes of such accidents, leading researchers to study new shear reinforcement to minimize them. The use of shear reinforcement is the most efficient way to increase punching shear ductility and strength, but its correct arrangement generates conflict with the flexural reinforcement. Thus, Ferreira et al. (2016) propose a prefabricated truss reinforcement positioned internally to the flexural reinforcement, which generated the patent number BR 10 2015 006518 3 A2. Therefore, the work carried out in this research contributes to the investigation of cases of bidirectional shear for the present reinforcement. In this research, 5 experimental tests of reinforced concrete flat slabs submitted to symmetrical loading, containing both Stud Rails and the pre-fabricated truss reinforcement proposed by Ferreira et al. (2016) as shear reinforcement, were carried out. The study evaluated the performance of the reinforcement in relation to punching shear strength and analyzed the upper limits of strength, since a flexural reinforcement ratio of 2% and shear reinforcement ratios around 1% were used. The slabs were octagonal with a 2500 mm distance between parallel faces, side of 1036 mm and thickness of 210 mm, cast with concrete around 30 MPa and supported on columns with 400-mm-side. The following variables were analyzed: shear reinforcement type, slope and spacing of the shear reinforcement layers, as well as the design parameters of ACI 318 (2014), EC2 (2014), ABNT NBR 6118 (2014) and ETA 12/0454 (2012) codes. The experimental results show that the increase of load, in relation to the slab without shear reinforcement, reached up to 92%, with the use of pre-fabricated truss reinforcement, and 101% with the use of Studs, showing that the upper limit of ultimate load as a function of the concrete strength (Vu/Vc) can be limited to 2 and that the reinforcement studied in this research has a high commercial potential, since its cost per increment of load was lower than the one of the slab reinforced with Studs Rails, except for the design criteria suggested by ETA 12/0454, reducing the total cost by 15.6%.
Acesso aberto (Open Access)
Aplicação de técnicas de identificação de sistemas para previsão de resistência à punção em lajes lisas de concreto armado sem armadura de cisalhamento
(Universidade Federal do Pará, 2019-02-27) AMORIM, Fábio de Oliveira; FERREIRA, Maurício de Pina; http://lattes.cnpq.br/4242041552985485; BAYMA, Rafael Suzuki; http://lattes.cnpq.br/6240525080111166
The structural systems used in reinforced concrete pavements, in which the slabs rest directly on the pillars, without the use of beams, have, among their characteristics, the existence of high concentrated stresses in the slab-pillar connections. These tensions can cause these connections to rupture and cause the structure to collapse progressively. This is called a punching. As the breakage of the punching bonds is fragile, without warning, it is extremely important that the bond strength is checked. For the study in question, information was collected from two databases of several authors who performed experimental tests on plain slabs of reinforced concrete without shear reinforcement, containing several parameters used in the tests, as well as punching resistance values. A lot of studies were developed with the purpose of defining and standardizing procedures and mathematical functions that satisfactorily represented the phenomenon of punching in function of its various parameters of influence. In this way, calculation models and normative instructions have been developed that can be used for the study and development of the subject. Besides, some studies were developed with the rescue of numerical techniques and systems identification, resulting in equations that aim to represent the punching phenomenon satisfactorily. The present work aims to obtain a mathematical function that represents the phenomenon of punching in slabs without shear reinforcement by means of their strain strength, or even group of functions, if this is the case. Therefore, it was possible to propose improvements in the equations present in the norms. The results show that it is possible to predict new mathematical models that describe the phenomenon of punching by means of systems identification techniques. The results also show that it is possible to propose better mathematical models when evaluating better performance metrics than the equations derived from normative data through statistical data. Thus, it is concluded that new mathematical models can serve as reference for engineers of the area of structures and researchers of related areas.
Acesso aberto (Open Access)
Avaliação da resistência ao cisalhamento em vigas de concreto armado reforçadas com macrofibras sintéticas
(Universidade Federal do Pará, 2019-02-01) SOUSA, Diego Lucena de; TEIXEIRA, Marcelo Rassy; http://lattes.cnpq.br/8912916360456192
With the increased use of composite materials, in search of adding to the new technologies, and, through the application in synthetic fiber contents to the concrete, this material can add favorable characteristics in relation to the conventional concrete. From this finding, the present study applied 0.08%, 0.12% and 0.16% for polypropylene fiber and 0.24%, 0.36% and 0.48% for polyethylene fiber in reinforced concrete beams so that the appropriate contributions could be evaluated, when this element was subjected to shear stress. Thus, after the tests, it was possible to observe that the elements with fiber application obtained a resistance above, however, close to the beam produced with the reference concrete. In contrast, as the contents of both fibers were increased, it obtained a ductility increment, a fact proven by the graphics shear x vertical displacement, shear x concrete deformation and shear x bending armor deformation, since, among the fiber contents used, the percentages of 0.36 % and 0.48% of polyethylene and 0.16% of polypropylene were the ones that presented a critical volume corresponding to the fiber content closest to an ideal, thus demonstrating the proximity of the carrying capacity for such produced composite, from the rupture of its matrix. Therefore, according to Figueiredo (2000), the behavior change is a function of the fibers characteristics, the concrete matrix and their interaction. In this way, the material now has specific requirements for its quality control, dosage and even application, different from conventional concrete. In view of this, it can be stated that the application possibilities of the material are amplified, since the reinforced concrete with fibers presented technological advantages in relation to the conventional one, as it showed a more ductile behavior, absorbing na equal load capacity for a longer period of time.
Acesso aberto (Open Access)
Concreto auto adensável com agregado miúdo reciclado de concreto
(Universidade Federal do Pará, 2019-03-29) BERNARDO, Karen Suely Martins; CORDEIRO, Luciana de Nazaré Pinheiro; http://lattes.cnpq.br/9126233381230999; https://orcid.org/0000-0001-7931-4042
A more sustainable approach in the production of self-compacting concrete (SCC) aims to replace the natural aggregates by recycled concrete aggregates, however this substitution affects the properties of the concrete produced. This research propose evaluate the effect of the fine recycled aggregate on the properties in the fresh and hardened state of self-compacting concrete using a methodology of dosage focused on the rheology of materials. The dosage study was performed through an adaptation of the Gomes method, and four levels of FNA substitution by FRCA were determined (10%, 20% and 30%). Were analyzed the fresh state properties according to the parameters established according to the specifications on the subject and by the normative prescription of reference, and the properties in the hardened state. In this study, was observed a decrease in apparent viscosity, passing ability and segregation resistance, proportional to the increase in FNA substitution. However, all mix designs have attend the required of self-compacting, with minimum adjustments. All concretes obtained axial compressive strength at which fit in the structural concrete class. Therefore, through the responses founded during the dosing study, it was possible to produce self-compacting concretes with 30% of FRCA that met the requirements established.
Acesso aberto (Open Access)
Desenvolvimento de um aplicativo móvel para promover o reaproveitamento de resíduos na dosagem de concreto
(Universidade Federal do Pará, 2019-09-04) MESQUITA, Felipe José Marques; FÜLBER, Heleno; http://lattes.cnpq.br/5018616409948511; ISHIHARA, Júnior Hiroyuki; http://lattes.cnpq.br/3498874642887006; https://orcid.org/0000-0002-0081-7913
Concrete is the most widely used building material in the world, resulting in high consumption of natural materials, thus, the reuse of waste in substitution of cement and aggregates in the production of concrete enables reduction of greenhouse gas emissions, reduction in extraction of natural raw materials, in addition to the reduction on the disposal of these wastes in nature. Given the need to develop solutions that contribute to the efficient reuse of waste, this paper aimed to analyze the state of the art of national production of concrete with waste reuse, to develop a mobile application to promote the reuse of waste in concrete production. Through bibliometric analysis of Brazilian publications on concrete with reuse of waste, we analyzed works published over a period of 20 years in the Web of Science database, revealing growing interest on the subject, especially the construction and demolition waste, being this the most published and protagonist residue of the most influential article on the subject. The analysis of the publications allowed the creation of a knowledge base on the use of waste in concrete production. These data were used in the development of an application for Android mobile devices, which allows the user to have easy access to concrete dosages with reuse of residues, obtain information on potential waste suppliers and calculate the production costs of this concrete. The system has 41 different mix proportioning, including 7 concrete types and 10 waste options, allowing the user to achieve environmental gains by replacing up to 100% of natural concrete aggregates with waste and saving up to 11.82% over cost. of concrete produced without waste. Keyword: concrete, waste, database, application, bibliometrics.
Acesso aberto (Open Access)
Dimensionamento de soluções acústicas para máquina aplicada à extração de fibras do pseudocaule da bananeira
(Universidade Federal do Pará, 2020-02-28) SILVA, Geanilson Brito da; MESQUITA, Alexandre Luiz Amarante; http://lattes.cnpq.br/3605920981600245; https://orcid.org/0000-0001-5605-8381
The Lake Tucuruí Integration Region (RI) stands out for its banana production in the state of Pará, making it one of the main producers of the fruit. However, the income of farmers in the region with banana production is restricted only to the sale of the fruit, discarding the other parts of the banana tree, which can be used to manufacture products with higher added value. With the use mainly of the fibers of the banana pseudo-stem, several products can be generated, boosting the development of banana cultivation in the region and promoting an increase in employment and income. Aiming at this socioeconomic growth of the RI Lago de Tucuruí, the present work presents, in its first part, an analysis of the fiber extraction machine of the banana pseudo-stem at the Federal University of Pará, Campus de Tucuruí, which will serve the small producers and cooperatives of farmers in the region. In the operation of the machine, it was found that it has noise problems. The sound pressure levels measured around the machine are above the normative limits. Thus, studies were carried out to define acoustic solutions aimed at solving the problem. In the second part, the main focus of this work is to present the acoustic solutions for the fiber extraction machine, including the specification of vibration isolators, replacement of the electric motor fan and dimensioning of the partial enclosure of the machine.
Acesso aberto (Open Access)
Dispersão de energia em um cristal granular hexagonal decorado
(Universidade Federal do Pará, 2024-02-29) RAMOS, Jorde Anthonny Alves; MACHADO, Luis Paulo Silveira; http://lattes.cnpq.br/0702289670734922; https://orcid.org/0000-0003-1587-3632
The decorated hexagonal granular crystal consists of main spherical grains arranged in a two-dimensional hexagonal array, with small spherical grains filling the interstitial spaces. These additional grains barely touch the main grains, increasing the number of contacts per grain. Additionally, all grains are initially at rest, with null velocities. For comparation, we used results from a similiar arrangement without decoration (i.e., without interstitial grains). We investigated the mechanical responses of both granular arrangements to the punctual incidence of an external grain. Our analysis focused on how the mechanical energy is dispersed and mitigated after a single initial impact. The proposed model confirmed the significant role of interstitial grains in the granular crystal. The decorated arrangement demonstrated accelerated behavior of the energy wavefront, both in its mitigation and propagation. In our analysis of energy scattering orientations, we found that the decorated arrangement exhibits greater energy mitigation and reorientation of return energy compared to the undecorated arrangement. Thus, the addition of interstitial grains promoves a greater return of mechanical energy to the external medium of origin. We conclude that with proper decoration, a granular crystal could act as a barrier against strong impacts.
Acesso aberto (Open Access)
Formulações de argamassas autonivelantes para contrapiso com incorporação parcial de agregado reciclado de concreto
(Universidade Federal do Pará, 2019-01-21) OLIVEIRA, Thais Valadares; CORDEIRO, Luciana de Nazaré Pinheiro; http://lattes.cnpq.br/9126233381230999; https://orcid.org/0000-0001-7931-4042
Self-leveling mortar is a material with advantageous characteristics for the industry of civil construction, among them: high flatness, low thickness of the elements that use it, rapid application and short demand of labor for its execution. In order to add knowledge about this material, as well as to make it more sustainable, by incorporating recycled concrete aggregates in its mixture, the present work was proposed. The main objective was to build self-leveling mortars with incorporation of these residues and to characterize them in the fresh state, verifying the technical feasibility of their use. Furthermore, in a complementary manner, it was observed how different combinations of additives may influence the properties of these mortars. Based on the use of a base formulation, available in the literature, eight traces were produced, including four variations of replacement of common sand by recycled aggregate (0%, 25%, 50% and 75%) and two possible combinations of additives, one employing in parallel a superplasticizer additive and a viscosity modifying additive and another in which only one polyfunctional plasticizer additive was applied. Initially, each mixture passed through individual adjustments so as to have adequate consistency, flow time and visual configuration, without demonstrating the occurrence of exudation or segregation. Thereafter, fresh tests were carried out to verify exudation, mass density, incorporated air content and curing time of the mortars. At the end of the research, it was noticed that the incorporation of recycled aggregate in self-leveling mortars could be a technically feasible option, and even advantageous for the mortars formulated with it, considering the evaluated properties, by reducing, among the mixtures with the residue and those ones of reference, the amount of additive employed (up to 0.2%), the exudation (the quantity of water exuded reached 2.04% in a mixture with recycled aggregate and 2.61% in a mixture of reference), the incorporated air content (ranging from 0.17% to 1.34% between traces with and without recycled aggregate) and the mass density (reduced up to 5.5%). Among the combinations of additives, in turn, it was observed that the most satisfactory was the one that employed polyfunctional additive.
Acesso aberto (Open Access)
Identificação de danos em estruturas usando modelo preditor baseado em técnicas de aprendizagem de máquinas
(Universidade Federal do Pará, 2019-10-04) BONA, Vanessa Cordeiro de; BAYMA, Rafael Suzuki; http://lattes.cnpq.br/6240525080111166; MESQUITA, Alexandre Luiz Amarante; http://lattes.cnpq.br/3605920981600245; https://orcid.org/0000-0001-5605-8381
The increase in the number of new buildings and the existence of countless old buildings, whether small or large, call attention to the need for measures that maintain the quality, safety and useful life of the structures. Inspections and monitoring, regardless of the age of the building, are essential to detect the existence of damage, especially in its initial phase, avoiding its propagation or serious consequences that originate due to a collapse of the structure, due to the high degree deterioration and no recovery techniques. Based on these aspects, this dissertation has the general objective of detecting damage in structures using the machine learning approach, which integrates three techniques: initially the Ensemble Empirical Mode Decomposition (EEMD) is applied a processing of the signals and seeks to adapt them for the application of the Auto Regressive Model (AR) generating the attributes, which will serve as input patterns for the Support Vector Machine (SVM) classifier. The data used to apply the methods come from the modeling of bi-supported steel beams, intact and with damaged regions, by the SAP 2000 Structural Analysis Software. With reference to the creation of the structures by finite elements, two types of loads were applied . The first case of random loading acting in only one point of the beam and the second case with three simultaneous loads in three points of the beam. According to variations in the location and degree of severity of the damage, the study sought to assess the ability of the predictive models to classify the data correctly. In the analyzes with greater mass losses, the accuracy values are higher, decreasing according to the reduction of the damage geometry, as the signs of displacement become similar to the integral structure. Regarding the number of loads, the method demonstrated better performance and accuracy in cases with three simultaneous loads.
Acesso aberto (Open Access)
Influência das armaduras complementares na resistência ao cisalhamento de vigas com estribos treliçados pré-fabricados
(Universidade Federal do Pará, 2019) PINTO, Rosângela Silva; LIMA NETO, Aarão Ferreira; http://lattes.cnpq.br/0287664572311345; https://orcid.org/0000-0002-5911-1368
In the design of structures under great loads, conflicts with the assembly of longitudinal and transverse reinforcement may happen. To avoid this type of occurrence, internal shear reinforcement may be a good option as they are inserted between longitudinal bars. However, if an anchorage failure occurs, a secondary effect caused by the use of these bars may cause a horizontal failure called (delamination). In order to prevent this failure, NBR 6118 (2014) states that stirrups anchorage must be secured by the use of hooks or welded longitudinal bars. Currently, few researches evaluate the influence of complementary reinforcement (hooks), and these are limited to an overall analysis of the specimens. Besides conflict with the assembly of densely reinforced members, another factor that may compromise their mechanical performance is the positioning angle of the transverse reinforcement. According to Eurocode 2 (2004), the use of reinforcement bars at an angle of 90º does not present fully satisfactory behavior, which indicates that different angles would result in more efficient responses. This research experimentally analyzes the influence of the complementary reinforcement anchorage, fixed in the compression and tensile zones of reinforced concrete beams, as a reinforcement for the stirrups. Seven RC beams using pre-fabricated truss internal stirrups were used, assessing the influence of the complementary reinforcement and verifying the behavior of stirrups at an angle of 90º or 60º in relation to the horizontal axis of the specimen. Some variations of the complementary reinforcement (hooks) ratio and the spacing between stirrups were made. As conclusions, it was observed that the use of complementary reinforcement to the pre-fabricated truss stirrup resulted in an increase of nearly twice the shear strength in relation to the reference beam, avoiding delamination until the failure load. The specimens with complementary reinforcement on both faces presented higher strength and ductility when compared to beams with complementary reinforcement only in the lower face. Strains increased from 2.46‰ in beam Wc-0.4-60b1 to 3.20‰ in beam Wc-0.4-60a1, showing that its use results in transferring stresses to shear reinforcement. On the behavior of beams Wc-04-90, by reducing the spacing between stirrups in 40 mm, they presented superior performance in terms of ductility and shear strength compared to beams Wc-04-90 with spacing of 100 mm.
Acesso aberto (Open Access)
Procedimentos experimentais para avaliação da emissão de poeira em manuseio de minério
(Universidade Federal do Pará, 2018-11-29) SANTOS JUNIOR, Ronaldo Menezes dos; MESQUITA, André Luiz Amarante; http://lattes.cnpq.br/1331279630816662
The generation of dust during the handling and transportation of bulk causes a series of problems, such as the erected air and loss of valuable material. Due to the risk associated with inhalation of dust, several control mechanisms have been adopted. The use of water is a viable option to inhibit the generation of dust, although the use of chemical suppressants is in some cases more appropriate. However, standards and methods for characterizing the generation of particulates are not very consolidated in the literature, for the proper selection of the control mechanism. Therefore, this study aimed to develop test methodologies to evaluate the emission of minerals particulate. The emission of particulate during transport was evaluated in a test bench developed by adapting an existing wind tunnel, using a wagon model and air speeds of 40 km/h and 70 km/h, for different iron ore moisture values. Results show that the increase in flow speed increases the loss of material mass contained inside the wagon model and the increase in material moisture significantly reduces the loss of mass, being enhanced with the use of dust suppressants applied to the material surface. To simulate material handling, a bench was developed using the dust tower technique concept, which allows dust generation tests during material discharge. In the results obtained, it is also verified that the increase in material moisture significantly reduces the emission of particulates, being more evident for materials that have a higher percentage of fines. The influence of suppressants was also evaluated, and among the tested reagents Fe2(SO4)3 showed the best result for the pellet feed milled, greatly reducing the emission of particulates in relation to the use of water only. For pellets, Ca(OH)2 showed the best results without curing time and CaCl2 for the condition with curing time of 2 hours. Therefore, the results show that the benches and experimental procedures developed, presented satisfactory and coherent results, which are reliable for the characterization of the emission of particulates from different materials.