Dissertações em Engenharia de Infraestrutura e Desenvolvimento Energético (Mestrado) - PPGINDE/NDAE/Tucuruí
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Item Acesso aberto (Open Access) Avaliação da influência de sistemas de proteção na permeabilidade de água em placas cimentícias com incorporação de perolas de poliestireno expandido(Universidade Federal do Pará, 2025-04-24) GOMES, Saulo de Almada; CORDEIRO, Luciana de Nazaré Pinheiro; http://lattes.cnpq.br/9126233381230999; https://orcid.org/0000-0001-7931-4042Water is one of the main elements responsible for the emergence and propagation of pathological events in coatings. Its permeated presence compromises the protective capacity, as well as directly influences durability, and can accelerate the deterioration of mortars, impairing their useful life. It is known that the use of surface protection instruments (painting system) and the use of waterproofing additives in the production of mortar coatings directly influence the protection against water permeability. Within this aspect, this study aimed to evaluate the degree of influence of protection systems for cement boards with the incorporation of Expanded Polystyrene (EPS). EPS was used in the cement board as a partial replacement for sand, in a volume of 20%. Two types of painting systems were evaluated, one for indoor environments and the other for outdoor environments, in addition to a type of waterproofing water-repellent additive, which was applied to the mortar mixture. This evaluation was carried out using two methods that analyze the permeability of mortar coatings: the Karsten tube test (pipe method) and the permeability test of ABNT NBR 15498/2021, which deals with the requirements for using cement boards. The mechanical properties of the mortars and boards were also characterized. The results of this work demonstrated that the protection systems evaluated caused different effects on the permeability of the boards. The waterproofing additive did not significantly influence the permeability of the panels, only the physical characteristics, with greater emphasis on the mass density and water absorption properties. The painting systems positively influenced the waterproofing capacity of the panels, with the external painting system being more efficient. Regarding the permeability assessment techniques, the Karsten tube showed great variability in the results, demonstrating that this technique is more sensitive to the conditioning variables. And, in the permeability test of NBR 15498, all panels passed the use requirement.Item Acesso aberto (Open Access) Análise experimental do desempenho à flexão de vigas de concreto armado reforçadas com laminado de fibra de carbono com variação da taxa de armadura existente e do mecanismo de ancoragem(Universidade Federal do Pará, 2025-06-17) LEÃO JÚNIOR, Paulo Sérgio Barreiros de; LIMA NETO, Aarão Ferreira; http://lattes.cnpq.br/0287664572311345; https://orcid.org/0000-0002-5911-1368The strengthening of existing reinforced concrete structures with Fiber-Reinforced Polymers (FRP), using techniques such as Externally Bonded Reinforcement and Near-Surface Mounted, is common in practical applications, especially when using Carbon FRP (CFRP). However, in strengthening scenarios that require higher load capacities, these methods may be less effective due to premature debonding failure, highlighting the importance of anchorage systems to improve reinforcement efficiency. There is limited information in the literature regarding the influence of steel reinforcement ratio on the behavior of beams strengthened with anchorage systems. Therefore, this study experimentally investigates the flexural performance of reinforced concrete T-beams strengthened with CFRP, considering two steel ratios (0.44% and 1.12%) and two anchorage systems. Flexural tests were conducted on six T-section beams (2200 mm length, 280 mm height, 180 mm web width, and 80 mm thick by 350 mm wide flange). Each beam had 21 stirrups made of 12.5 mm bars spaced at 100 mm. For each steel ratio, one beam was unstrengthened (reference), and two were strengthened using either a friction-based mechanical anchorage (Hybrid Bonded – HB) or an anchorage system using bonded CFRP strips (FT). Strengthening was more effective in beams with the lower steel ratio, with strength increases of 58% for HB and 11% for FT. For the higher steel ratio, gains were limited to 10% for HB and none for FT. The HB system achieved a flexural capacity of 117.72 kN·m and showed better performance in intermediate displacements, with ductility increases up to 57 times at cracking and up to 100% at steel yielding. At maximum load, all strengthened beams showed reduced ductility. In the HB system, ductility loss increased with steel ratio, from 25% in the less reinforced beam to 49% in the more reinforced one. In the FT system, the trend was reversed, with a 66% loss for the lower steel ratio and 24% for the higher. Failure modes were governed by laminate slip in HB and cover delamination in FT.Item Acesso aberto (Open Access) Análise experimental da influência de ancoragens e taxas de armadura na resistência à flexão de consolos longos reforçados com laminados de fibra de carbono(Universidade Federal do Pará, 2025-05-29) SILVA, Lucas Carvalho; LIMA NETO, Aarão Ferreira; http://lattes.cnpq.br/0287664572311345; https://orcid.org/0000-0002-5911-1368For the repair and strengthening of reinforced concrete corbels, solutions are sought that extend the service life of these structures, increase their load-bearing capacity, reduce deformations, and limit crack propagation. Therefore, this study presents tests on experimental models of corbels strengthened with Carbon Fiber Reinforced Polymer (CFRP) laminates to analyze the strength enhancement in these models. All corbels are chamfered and have the same geometry. Thus, the ratio between the load application point (a) and the effective depth (d) is approximately 1.28, allowing the behavior to be characteristic of either a corbel or a cantilever beam. All specimens have a geometric arrangement with 250 mm width, 400 mm embedded height, 200 mm height at the outer face, and 570 mm length. The main objective of this research is to analyze the behavior of the reinforcement according to the variation in the main reinforcement ratio and the anchorage method, to compare the experimental results with current standards, and to verify whether the proposed anchorage systems prevent premature failure modes. The reinforcement dimensions consist of a (50x1440) mm laminate applied to both faces of the corbel. Two configurations of the anchorage system were analyzed. The first anchorage method involves attaching bolts through plates that do not perforate the laminate, known as Hybrid Bonding (HB). The second method, classified as FT (based on the laminate application approach), uses the reinforcement laminates themselves, with overlapping layers — the final one being applied perpendicular to the reinforcement and previous layers. Regarding the results, it was observed that both anchorage methods are effective in increasing the strength of the specimens, with HB being the most suitable anchorage method. Furthermore, depending on the reinforcement ratio, the strength gains provided by the reinforcement vary, being less effective in corbels with higher main reinforcement ratios. Finally, it was noted that the proposed anchorage methods were not entirely effective in preventing debonding along the laminate. However, it is worth highlighting that in the corbels with HB anchorage, even with reinforcement debonding, the anchorage was able to prevent complete slippage, contributing to increased ductility of the corbel even after debonding.Item Acesso aberto (Open Access) Efeito da taxa de armadura existente e do sistema de ancoragem na resistência à flexão de consolos curtos de concreto armado reforçados com laminados de PRFC(Universidade Federal do Pará, 2025-06-13) LIMA, Layse Rafaele Furtado; FERREIRA, Maurício de Pina; http://lattes.cnpq.br/4242041552985485; https://orcid.org/0000-0001-8905-9479Short corbels are elements used in bridges and buildings to support beams, stringers or concentrated loads of great intensity, and are characterized by having a span-to-height ratio of less than one. Over the course of their useful life, these structures can fail to meet basic safety requirements for reasons such as design error, material degradation, overload or change in use, requiring reinforcement techniques that can be applied quickly and efficiently. With this in mind, this work seeks to experimentally analyze short reinforced concrete beams reinforced externally in bending with Carbon Fiber Reinforced Polymer (CFRP) laminates. To this end, six specimens were analyzed, three with a 0.18% flexural reinforcement rate and three with a 0.47% rate. All the models have the same geometry, with the presence of horizontal and vertical stirrups. The reinforcement was positioned on both sides of the cantilever and anchored at the ends, checking the influence of two systems. The first anchoring system is made up of steel plates and bolts, while the second is made up of overlapping laminates, with transverse bonding in the last layer. As a result, it was possible to analyze that the reinforcement proved to be efficient in terms of increased resistance, which ranged from 14,5% to 50,3%, with the hybrid anchorage standing out as having the highest loading value.Item Acesso aberto (Open Access) Análise experimental de consolos curtos de concreto armado com fibras e variação da armadura de costura(Universidade Federal do Pará, 2023-11-23) QUEIROZ, Daniel Pessanha de; LIMA NETO, Aarão Ferreira; http://lattes.cnpq.br/0287664572311345; https://orcid.org/0000-0002-5911-1368Short armoured concrete consoles are pre-molded structural elements, arranged in balance, which function as a load support. This work aims to analyze experimentally the behavior of short consoles of armed concrete with variation of sewing armour area and application of a fixed content for steel fibers, polyethylene and polypropylene. Ten symmetrical specimens were analyzed, where four speciments did not contain sewing armor and possessed respectively the steel fibers (CA), polyethylene (CPE), polypropylene (CPP) and a fiber-free (CSF). Four specimens with six sewing armor Ø6.3 mm and used steel fibres respectively (C6Ø6.3A), polyethylene (C6Ø6.3PE), polypropylene (C6Ø6.3PP) and a fiber-free (C6Ø6.3SF). One specimen with six armor Ø5.0 mm seam and polyethylene fiber (C6Ø5.0PE). One specimen with eight armor Ø5.0 mm seam with polyethylene fiber (C8Ø5.0PE). They are presented, analyzed and discussed the results of: deformations of concrete and main traction armor and sewing; breaking modes; cracking maps and patterns; end resistance and loads of consoles; as well as the efficiency factors of biela, subsequently these topics above should be compared with those obtained by Abrantes (2019) and with what advocates the regulatory standards ABNT NBR 9062 (2017), NBR 6118 (2023), EUROCODE 2 (2010) and ACI 318 (2014). It is concluded that they have achieved better results compounds that received the addition of fibers. In terms of compression, traction and modulus of elasticity, comparing the matrix without and with fibres, polyethylene was 15%, steel 18% and polypropylene 21% more efficient, respectively. It can be seen that for each test a different fibre performed better. In general, C8Ø5.0PE achieved good results in all analyses, despite not being the specimen with the largest seam reinforcement area. This result is justified by the arrangement of the reinforcement inside the concrete, as well as the presence of the polyethylene fibre.Item Acesso aberto (Open Access) Proposta de metodologia para diagnóstico de falha em rolamentos de baixa velocidade(Universidade Federal do Pará, 2024-04-19) COSTA, Thiago Barroso; MESQUITA, Alexandre Luiz Amarante; http://lattes.cnpq.br/3605920981600245; https://orcid.org/0000-0001-5605-8381Monitoring low-speed bearings with vibration analysis is more challenging due to the low energy level of the vibration signal that carries the failure data, making it more susceptible to interference from other sources, impairing the interpretation of information. Thus, an alternative is to calculate signal predictors that may be sensitive to pattern changes relative to failure onset and progression. Hence, the present work extracted different types of features, among them two nonlinear features and eleven extracted from the signal in the time domain. Those features were ranked and selected based on their sensibility to class differentiation, which was estimated using the t-Welch statistic value. Among them is the Largest Lyapunov Exponent, which, in this work, had a modification in one of its calculation steps, improving its sensitivity in some cases. In addition, the influence of the vibration signal window size on the class separability of the indicators was evaluated (which is a scarce content in low-speed bearing monitoring literature). After feature selection, the data were subjected to a linear transformation through PCA (Principal Component Analysis), aiming to reduce the data dimensionality to three dimensions and to minimize the redundancy effects of highly correlated features. In sequence, the data represented in the space of principal components were projected on a Hotelling T2 statistic control chart. The chart allowed the detection and rejection of potential outliers, which consisted of points above a limit line estimated based on F statistic distribution. Finally, binary and multiclass Support Vector Machine classification models were trained with experimental data acquired from normal conditions and three levels of incipient fault in bearing. The models performed well, mainly the binary model with test data obtained from belt conveyor pulley bearings in industrial operation.Item Acesso aberto (Open Access) Experimento em escala de emissão de poeira no processo de empilhamento(Universidade Federal do Pará, 2022-03-25) CASTRO, Maycon Magalhães; MESQUITA, André Luiz Amarante; http://lattes.cnpq.br/1331279630816662; MACHADO, Luis Paulo Silveira; http://lattes.cnpq.br/0702289670734922; https://orcid.org/0000-0003-1587-3632Dust emission can lead to health problems, explosion risk, material segregation and environmental pollution. Therefore, it is necessary to understand the parameters related to dust generation to improve particulate emission control techniques. Dust reduction based on spray spraying is the main method to prevent and control dust emission in ore stacking. Dust suppression techniques at conveyor belt transfer points can be subdivided into material spraying and trapping of fugitive particles. To analyze the parameters associated with dust generation during ore stacking, a scaled conveyor bench was developed for dust suppression tests via water spray. This installation is equipped with spray nozzles whose relative location on the belt can be adjusted and the speed of the conveyor can also be controlled. The spray jet is provided by a set of spray module and flow divider, allowing the variation of the system pressure and with the possibility of using suppressors, which can increase the efficiency of particle capture. Dust suppression performance is analyzed by monitoring strategic points with the highest dust emission. The results of this investigation show that dust generation increased as the drop height increased, it was observed that the region close to the pile emits a higher concentration of dust, due to the impact of the material flow on the stacking surface, in compared to the front region of the flow. The results after using the spray on the belt showed that the highest drop height (1600 mm) emitted the highest concentration of particles (3192.72 μg/m3) after spraying, on the material, the dust concentration reduced by about almost 70%, showing the efficiency of spray humidification. It was also observed that PF has a higher critical humidity than that of SF, as well as that it emits a higher concentration (1116.52 μg/m3) compared to Sinter feed (848.14 μg/m3), making it evident that by as it is a material with a smaller granulometry, the pellet feed tends to emit a higher concentration of particulates when handled.Item Acesso aberto (Open Access) Análise experimental da influência da adição de fibras e da variação da armadura de costura em consolos curtos de concreto armado(Universidade Federal do Pará, 2022-06-23) BRANDÃO, Jaciara Santos; LIMA NETO, Aarão Ferreira; http://lattes.cnpq.br/0287664572311345; https://orcid.org/0000-0002-5911-1368Reinforced concrete corbels are usually characterized by being support elements whose design can be made from the Strut-and-Tie Method (STM) which is based on fundamental assumptions that consider that the tensile stresses are absorbed by the rods (structural steel) and the compressive forces are absorbed by the struts that are formed inside the concrete section, as it is understood that these elements have regions of discontinuity (D) or disturbances in the stress distribution. This method can be applied in the case of short corbels as they also present regions (D), given that their stress flow occurs in a non-linear manner. In this way, this experimental study analyzed the influence of the addition of synthetic fibers (polyethylene and polypropylene) and steel in the composition of the concrete, as well as, to verify the influence of the variation of the seam reinforcement rate in order to validate the MTB as a solution safe and efficient for the design of elements that present discontinuities (D) or disturbances. In the tests, the breaking load, the opening of cracks and the deformations in the tie rods, seam reinforcement and in the concrete, internally and externally, were observed. The results showed that the specimens containing synthetic fibers showed the highest strengths compared to the steel fiber specimen, being on average 10.82% more resistant than the reference specimens, despite not containing the highest fiber contents. In general, the elements showed similar ductile behavior and failure mode, so the cracks occurred in a controlled manner and there was no sudden rupture. As for the deformations in steel and concrete, the results showed a similar behavior among the specimens.Item Acesso aberto (Open Access) Desenvolvimento de túnel de vento para avaliação de bicos de pulverização no abatimento de poeira(Universidade Federal do Pará, 2024-12-20) SANTOS, Danilo Silva; MESQUITA, André Luiz Amarante; http://lattes.cnpq.br/1331279630816662Mining is extremely important economically and socially for the industry, especially iron ore, but along with its benefits, it also has environmental impacts generated in different ways, such as dust. This inconvenience has caused disruptions to mining enterprises, such as production shutdowns and heavy fines, as well as problems for people who work in the companies and surrounding communities, due to health problems associated with inhaling dust and dirt from the environments, making them unhealthy and devalued. Dust control mechanisms have been widely studied and one of these is dust control using spraying of suppressant solutions. Studying the efficiency of spray nozzles has become of great importance and bench tests act as efficient means of understanding the mechanism of dust abatement from minerals. Research has been common to use wind tunnels. Thus, a tunnel was built capable of evaluating 5 different nozzles and their efficiencies in suppressing pellet feed and sinter feed at two speeds and different water pressures. It was concluded that the tunnel is capable, through the methodology used, of evaluating and comparing the best nozzle, demonstrating that it is an important tool in consolidating this knowledge in the Fluid Dynamics and Particulates Laboratory.Item Acesso aberto (Open Access) Protótipo para análise técnico-econômica de bombas funcionando como turbinas em redes de distribuição de água(Universidade Federal do Pará, 2025-02-27) VIANA, Ingrid Luna Baia; SOUZA, Davi Edson Sales e; http://lattes.cnpq.br/6130270007673176; HTTPS://ORCID.ORG/0000-0001-9632-5667; ISHIHARA, Júnior Hiroyuki; http://lattes.cnpq.br/3498874642887006; https://orcid.org/0000-0002-0081-7913The growing need for sustainable solutions in water distribution networks requires technologies that optimize energy efficiency and reduce operating costs. However, choosing the best alternative for implementing Pumps Operating as Turbines (BFTs) is challenging due to the multiple technical and economic criteria involved. Therefore, this study proposes a decision support model, employing multicriteria techniques and computer programming to assist in selecting the most viable alternative within different scenarios. The analysis focuses on the technical-economic feasibility of BFTs in Water Distribution Networks (RDAs), using the TOPSIS method, where data will be evaluated and classified by similarity to ideal conditions. Implemented in Python, the system ensures calculation accuracy, with a graphical interface called FliessEnergy, hosted by Vercel, with a responsive and scalable layout, providing an optimized user experience. Practical application with real RDA data demonstrated its effectiveness in prioritizing the most advantageous alternatives. The results indicated that Scenario 1 presented the best configuration for implementing BFTs, while Scenario 5 was the least favorable alternative. This classification of alternatives helps managers make decisions, taking into account both the proximity to the best conditions and the distance from the worst. To assess the reliability and consistency of the codes, PyTOPS, free software that allows several simulations with changes in the weights of the criteria, was used. A total of 500 simulations were performed, resulting in reduced variability between the scenarios, which reinforces the robustness of the model and its ability to generate consistent classifications even with small changes in the parameters. The model proved consistent and reliable, offering a useful instrument for evaluating the implementation of BFTs in RDAs. It is expected that, with future improvements and integration of databases, this solution can contribute significantly to strategic decisions in the sanitation sector in Brazil.Item Acesso aberto (Open Access) Projeto e fabricação de extrusora monorrosca com matriz de extrusão filamentar(Universidade Federal do Pará, 2024-10-25) RODRIGUES, Rodimilson Coelho; EL BANNA, Wassim Raja; http://lattes.cnpq.br/2005046563115507; HTTPS://ORCID.ORG/0000-0001-5085-4352; NASCIMENTO, Walber Alexandre do; http://lattes.cnpq.br/8022410578951099; https://orcid.org/0000-0002-2699-3982Large industrial establishments are always looking for increasingly sophisticated technologies to monitor manufacturing processes. This work aims to design and build a laboratory single-screw extruder and its extrusion die for processing polymers and polymer composites, in addition to enabling studies in the area of mechanical recycling of polymers. The first stage of the work involved choosing the type of extruder to be manufactured. The second stage consisted of dimensioning and designing the equipment using Solidworks software. In the third stage, the types of materials and mechanical and electrical components for assembling the extruder were selected. In the fourth stage, the manufacturing processes of the extruder and assembly of the mechanical and electrical components were carried out. In the fifth stage, the equipment was validated, where temperature and mass flow tests were performed, in addition to mechanical and electrical tests in the processing of a thermoplastic polymer, which, in this case, was polypropylene (PP). The last stage consisted of simulating a die with a cylindrical profile, aiming to study the characteristics of the polymer melt flow and define how the die structure should be adjusted to obtain the desired diameter. After designing the die in Solidworks software, a simulation was performed in Ansys software. In this case, the rheological behavior of the melt as it passed through the die was studied through the simulation, analyzing in which part of it the high and/or low shear rates are observed when the polymer flows through it. The drag flow and pressure flow were then extracted from the simulation parameters, which led to the calculation of the operating point and operating pressure for the die. It was also possible to calculate the mass flow rate and the velocity drop at the die wall, in addition to optimizing the die profile for the circular shape and desired diameter.Item 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/0000-0003-1587-3632The 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.Item Acesso aberto (Open Access) Influência do espaçamento das armaduras de cisalhamento na resistência à punção de lajes lisas com estribos treliçados pré-fabricados(Universidade Federal do Pará, 2022-12-27) COSTA, Denilda Silva; FERREIRA, Maurício de Pina; http://lattes.cnpq.br/4242041552985485; https://orcid.org/0000-0001-8905-9479The shear check on the slab-column connection of flat slabs in reinforced concrete is the critical point of design in the ultimate limit state. Punching failure is the critical point in the design of flat slabs and is defined as a sudden and fragile failure due to shears in the region of connection between the slab and the column, the best option for the control of failure by flat slabs is to use of shear reinforcement. National and international regulations such as the use of shear reinforcements that involve bending reinforcements in a way that their anchoring is guaranteed. However, this model makes the executive process difficult, requiring configurations between the bending and shear protections at the construction site. This research aims to present a technical and constructive solution to the problem of shear resistance in flat slabs in the slab-column connection through the use of shear reinforcement proposed by Ferreira et al. (2016), prefabricated truss stirrups, varying the values of the shear reinforcement rates and the spacing between the reinforcement layers. Positioned between the upper and lower flexural reinforcements, it has speed in execution and the possibility of manpower, as it is industrially bent and positioned on the job site, the useful height of the slab and the economy eliminates conflicts between the shear and flexural reinforcements. To compare the results and analyze the performance, tests were carried out on 5 flat reinforced concrete slabs, one of the slabs was reinforced with a flexural reinforcement rate ρ 2,0%, and the others with ρ1%, the reinforcement rate of shear (ρw) varies from 0.49% to 0.99%. As the instrumented in a way that could be the non-designed displacement forms, as in the flexural, shear and complementary reinforcements. The slabs were instrumented so that the vertical displacements, the deformations in the concrete and in the flexural, shear and complementary reinforcements could be obtained. The slabs were dimensioned so that the failure occurred by punching within the region of the shear reinforcement following the normative calculation recommendations of NBR 6118 (ABNT, 2014), ACI 318 (2019), Eurocode2 (2014), fib Model Code 2010 (2013) and the EOTA technical report (2017). From the analysis of the results, it was concluded that all slabs failed by punching, the slabs reinforced with prefabricated truss stirrups showed a strength gain of 73% for the SW3 slab when compared to the reference slab (S0) from Freitas (2018) and of 55%, 58%, 45% and 50% for slabs SW4, SW5, SW6 and SW7, respectively, when compared with the predictions of NBR 6118 (ABNT, 2014), slabs with reinforcement positioned up to 1.125d from the column face showed higher strength increase values and ultimate strength values similar to those of slabs with constant spacing, even with reduction of the total amount of steel by up to 95,2% of its weight.Item Acesso aberto (Open Access) Resíduos de gesso na construção civil: uma análise bibliométrica na base de dados eletrônica Web of Science(Universidade Federal do Pará, 2021-11-05) FREITAS, Pablo Virgolino; ISHIHARA, Júnior Hiroyuki; http://lattes.cnpq.br/3498874642887006; https://orcid.org/0000-0002-0081-7913The construction sector stands out for the exploitation of natural resources and for the production of residues that, in the vast majority, are improperly discarded in nature, generating serious negative consequences for the environment. Aiming to minimize the harm caused by the poor disposal of Construction and Demolition Waste - CDW, as well as to develop alternative ways to replace natural raw material by recycled waste, many studies have been carried out. Among the materials that have high recycling potential is gypsum, whose residues are already being used as a binder, additives in Portland cement, soil correction, among other forms of recycling. Therefore, this study aims to analyze Brazilian and international scientific publications dealing with the reuse of plaster in civil construction, performing a bibliometric mapping in the Web of Science electronic database. The mapping was carried out through exploratory research related to the reuse of gypsum waste in several scientific articles. Words and expressions that had the highest frequency of occurrence in published articles were collected. The search in the database resulted in 89 articles, of which 42 contained information on the recycling of gypsum waste in civil construction. The selected articles belong to authors from 19 countries, the most representative being Brazil, with 13 articles. Through the VOSviewer software, network maps were elaborated, through which it is demonstrated how authors and scientific institutions relate in relation to the recycling of plaster waste. The results of the articles studied here compose a portfolio through which effective methods of reusing this waste can be verified, thus facilitating the search by third parties for this type of information. What can help in the formulation of public mechanisms that help to improve solid waste management in Brazil, because, through the social network Instagram, this information will be made available in order to reach an audience that goes beyond academic borders.Item Acesso aberto (Open Access) Desenvolvimento de sistema de diagnóstico de falhas em roletes de transportadores de correia(Universidade Federal do Pará, 2024-03-28) SOARES, João Lucas Lobato; MESQUITA, Alexandre Luiz Amarante; http://lattes.cnpq.br/3605920981600245; https://orcid.org/0000-0001-5605-8381Belt conveyors are essential equipment in mining industry and require constant monitoring to maintain good reliability. In order to support the belt and the material being conveyed, rollers are components that constantly fail during operation, in which they present faults in bearings and surface wear in the shell as the most common failure modes. Thus, monitoring based on predictive maintenance is essential, and machine learning techniques can be used as an alternative for detecting equipment failures. In diagnostics using machine learning, the feature selection step is important to avoid loss of accuracy in the classification of the equipment's condition. The present study analyzes the performance of the decision tree algorithm and Analysis of Variance (ANOVA) as alternative methods for dimensionality reduction. Initially, the vibration signals were collected on the rollers of a belt conveyor bench and the Wavelet Packet Decomposition (WPD) was applied to the signals to obtain the energy ranges, which were used as features for classification. After the determination of the best features, two approaches were analyzed for the selection of features: one with the application of the method without dimensionality reduction and the other with the application of the decision tree. In addition, different classification algorithms were used: Support Vector Machine (SVM), k-Nearest Neighbor (kNN) and Artificial Neural Network (ANN). As a result, it was found a superior performance of diagnostic accuracy in all techniques with a reduction in the dimensionality of the characteristics selected by the decision tree. In addition, SVM, kNN and ANN showed increases in accuracy ranging among the fault diagnosis models approached.Item Acesso aberto (Open Access) Viabilidade ambiental do tratamento do efluente industrial do dendê e uso na produção de biogás e biofertilizante(Universidade Federal do Pará, 2024-03-28) GOMES, Emanuelle Regina Araújo; ISHIHARA, Júnior Hiroyuki; http://lattes.cnpq.br/3498874642887006; https://orcid.org/0000-0002-0081-7913The effluents generated in the agro-industrial sector are produced in large quantities, especially those from the processing of a product for commercial use, as is the case with palm oil. In the search for alternatives for treatment and/or reuse, oil palm agro-industrial effluent can be used to produce bio-input and biofuel. The aim of this dissertation is to assess the feasibility of treating industrial oil palm effluent and using it to produce biogas and biofertilizer. The work methodology consisted of manufacturing 10 benchtop bioreactors, adapted with an automatic control system, which allowed quantification of pressure, temperature and methane concentration measurements through sensors, enabling treatment through the anaerobic digestion system of effluents. . For treatment, the effluent was inoculated with one of the solid materials resulting from the processing stages (palm oil sludge), and a physical-chemical analysis of the parameters was carried out. Finally, the system made it possible to quantify biogas production and characterize the biofertilizer generated in the system. The data analysis presented demonstrates that the POME treatment, combined with the inoculum, promotes better results for the physicochemical parameters analyzed in the research, given that the best conditions occurred for the 30% inoculum range, that is. 700 ml of effluent + 300 ml of inoculum, showing the environmental viability of the treatment. With regard to the production of biogas and biofertilizer, the indicators of temperature (20 to 45oC), pressure (1 atm) and daily methane gas production of between 0.26 and 0.44 ml in the anaerobic digestion system showed good operating conditions in the system, making their production feasible through the use of oil palm agro-industrial effluent, allowing an environmentally appropriate possibility for the waste, from the point of view of the production chain, the environment and the economy.Item Acesso aberto (Open Access) A influência dos agregados reciclados de resíduos da construção civil nas propriedades do concreto permeável: uma revisão sistemática(Universidade Federal do Pará, 2023-01-27) OLIVEIRA, Thainá Maria da Costa; CORDEIRO, Luciana de Nazaré Pinheiro; http://lattes.cnpq.br/9126233381230999; https://orcid.org/0000-0001-7931-4042Sustainable development in the civil construction sector has been increasingly promoting the advancement of research on sustainable technologies in order to mitigate the problems caused by this sector. In view of the above, a sustainable measure that aims to reduce the consumption of natural resources and the irregular disposal of waste is the practice of reuse and/or recycling of RCC, and as a solution to flood control, the use of permeable concrete (CPER) is proposed. Due to the lack of standardization and divergence of the procedures determined for the characterization of the CPER with recycled aggregate, it became necessary to analyze the scientific knowledge of this material and demonstrate the feasibility of using RCC in the production of the CPER. In view of the above, this research aims to contribute to the knowledge about the use of recycled aggregates in the production of pervious concrete, through the selection of articles in databases from the last 15 years, in order to evaluate the properties acquired by materials with different types, sizes and contents of recycled aggregates. The present research used the Systematic Literature Review (RSL) as methodology for conducting the study. The articles were collected from the four most prestigious scientific bases for publications on themes related to civil construction. To screen the articles and prepare the RSL, the StArt tool was used, and data extraction from the studies was defined in the research protocol prepared. The results showed that the subject gained more relevance in the year 2016, the Science Direct database presented the highest number of articles, 80% of the works used coarse aggregates in the production of CPER, the percentages of substitution most used among the researches were 100% and 50%. Structural and mixed concrete waste were the most used as recycled aggregates in the production of CPER. It was possible to note great dispersion between the data collected in the surveys and the component materials of the CPER. Moreover, it was found that all types of aggregates met the strength and porosity values determined by the ACI and the permeability met both standards, except for the glass waste. Thus, the application of recycled aggregate in the production of CPER was evaluated as an adequate solution to the problems of irregular waste disposal and shortage of natural aggregates.Item Acesso aberto (Open Access) Reação álcali-agregado: potencial reativo dos agregados miúdos provindos das jazidas dos municípios de Ferreira Gomes, Macapá e Porto Grande no estado do Amapá(Universidade Federal do Pará, 2024-02-29) FIGUEIREDO, Rodrigo Francklin Lopes; SOUZA, Paulo Sérgio Lima; http://lattes.cnpq.br/4933212993218783The concrete is one of the most employed materials in engineering, its performance and durability can be altered by various deterioration processes, making it essential that materials used in its composition be analyzed and suitable for each type of construction. Among these processes, there is the alkali-aggregate reaction (AAR), which is defined as a chemical process that occurs between the alkaline components of cement and certain types of reactive aggregates, which can result in the emergence of expansive products that cause structural damage to concrete (Neville, 1997). The objective of this work is to analyze the reactive potential of fine aggregates, specifically the alkali-reactive potential of 8 sand samples from the main deposits in the municipalities of Ferreira Gomes, Macapá, and Porto Grande in the state of Amapá (AP). The motivation for this research arose due to the lack of data regarding the reactivity of fine aggregates in the state and as a preventive measure against the occurrence of alkali-silica reaction (ASR). For this evaluation, the first test used was the accelerated mortar bar method following NBR 15577 - 4 (ABNT, 2018). In addition to this, the chemical method following NBR 9774 (ABNT, 2008) was employed as an auxiliary, as well as scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS) attached, in order to observe the microstructure of the bars, verify the presence or absence of products that evidence the occurrence of AAR, and through semi-quantitative elemental chemical analysis, identify the substances present in the bars. The results indicated in the accelerated method that the collected samples do not have deleterious potential, as the bars did not reach 0.19% expansion; the highest percentage of expansion was 0.12% in the Translima Deposit (J7), this innocuous behavior was confirmed with the use of the chemical method. Regarding the use of SEM, the formation of the gel related to ASR was not observed. Finally, the mapping of reactive aggregates was carried out, and it was found that the aggregates are innocuous and can be used satisfactorily regarding ASR.Item Acesso aberto (Open Access) Partidas e paradas em usinas hidrelétricas: atendimento ao ONS e custos operacionais(Universidade Federal do Pará, 2023-12-19) MACHADO, Jucileia Cruz; MESQUITA, André Luiz Amarante; http://lattes.cnpq.br/1331279630816662Hydroelectric plants (UHEs) connected to the National Interconnected System (SIN) have their operation under the rules of the National System Operator (ONS), which generate operational conditions that are often not suitable for the generating units, whether due to low efficiency or limit conditions. operation that affect maintenance, such as wear and cavitation. This work investigates the short-term dispatch process, a one-day horizon, for a large hydroelectric plant that is part of the national interconnected system (SIN). The Tucuruí hydroelectric plant was used as a base and case study, where data on generation, hydrology and the number of starts and stops of the installation were mapped, as well as the influence on costs associated with the number of intervention requests. A strategy is proposed to minimize the number of starts and stops, using the change of operating points of the generating units on the hill curve, observing the drop height, power and yield points possible to meet the system demand, without having to the need for successive starts and stops. The result of this investigation, for the year analyzed, obtained a reduction, for one operating day (24h), of around 26% in changes in status (starting and stopping) of the generating units, proving that it is possible to make adjustments at the points of operation of generating units, within the limits permitted by operational restrictions, with a focus on reducing starts and stops.Item Acesso aberto (Open Access) Influência da substituição de agregados naturais por reciclados de concreto na resistência à punção de lajes lisas de concreto armado com armadura de cisalhamento(Universidade Federal do Pará, 2023-11-21) PORTILHO, Shara Katharine Melo Silva; LIMA NETO, Aarão Ferreira; http://lattes.cnpq.br/0287664572311345; https://orcid.org/0000-0002-5911-1368This research experimentally analyzed the mechanical behavior of four reinforced concrete flat slabs with shear reinforcement, when subjected to punching shear forces. Two of these slabs were made using a concrete mixture with a total replacement of natural coarse aggregates (NGA) by recycled concrete coarse aggregates (RCCA), and two slabs served as reference (without replacement). Shear reinforcement had two types: double headed studs and individual stirrups. The specimens were octagonal in shape, with 2,500 mm between opposite faces, thickness of 210 mm, and were supported on square central columns measuring 300 mm on each side. The estimated average concrete strength was 25 MPa, and the flexural and punching shear were 1.4% and 0.34%, respectively. After the laboratory tests, a comparison was made between the experimental behavior and the theoretical predictions from ABNT NBR 6118 (2023), Eurocode 2 (2014), ACI 318 (2019), and the fib Model Code 2010 (2013) models. Regarding the use of shear reinforcement, the results showed that the slabs with double headed studs presented higher punching shear strength when compared to those with individual stirrups. It was also observed that slabs with a total replacement of natural coarse aggregates by recycled concrete aggregates presented lower punching shear strength than slabs with natural aggregates. Regarding the comparison between the estimated punching shear strength of the flat slabs with shear reinforcement using RCCA prescribed by the analyzed codes and the experimental results, it was found that almost all code predictions were very close to the experimental values, except for the Brazilian code, which indicated results against safety.