Artigos Científicos - CAMTUC
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/11430
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Item Acesso aberto (Open Access) Segurança de barragens de rejeitos e impactos ambientais: uma revisão sobre a mineração de caulim em uma região amazônica(Instituto Tocantinense de Educação Superior e Pesquisa, 2023-12) SILVA, Matheus Cavalcante; MOREIRA, Debora Dias Costa; ISHIHARA, Júnior Hiroyuki; MONTE, Christiane do Nascimento; SELFE, Ana Cristina Cavalcante; SOUZA, Jadelene Ramos de; FRANÇA, Carlos David VeigaIn Brazil, the state of Pará has received attention, especially for the production and processing of kaolin. On the other hand, the demand for such mineral inputs has led to the growth of tailings production, which represents risks, which can be evidenced in recent disasters involving mining dams. This study consists of a systematic bibliographical review and aimed at discussing related methods of processing, kaolin storage and numerous incidents involving waste leaks, in order to support actions to detect the most impacted areas. The results demonstrated that the processing of kaolin ore in the study area is carried out via the wet process. Kaolin tailings storage systems in Barcarena-PA are more unsafe in relation to alternative disposal systems, resulting in events of kaolin tailings leaking into regional water bodies and spreading areas used for bathing.Item Acesso aberto (Open Access) Resíduos de gesso na construção civil: um mapeamento bibliométrico na base de dados Web of Science(Universidade do Vale do Taquari, 2024) FREITAS, Pablo Virgolino; ISHIHARA, Júnior Hiroyuki; CORDEIRO, Luciana de Nazaré Pinheiro; VIEIRA, Geilma LimaThe present study aims to analyze the scenario relating to Brazilian and international scientific publications that deal with the reuse of gypsum plaster, carrying out a bibliometric mapping in the electronic database Web of Science (WoS) covering a period of twenty years, before and after CONAMA Resolution No. 431/2011, starting in 2001 and ending in 2020. Data collection began through exploratory research, where words and expressions were collected in abstracts and keywords from scientific productions related to the topic to create word clouds. In order to identify the scope of the three words identified as translations for gypsum plaster, an initial search was carried out in order to understand their return in numbers; then, search terms were created for searches for the three translations of the word gypsum, and a search term containing them all. The article data was exported to EndNote web, where the articles were selected, and later, using the VOSViewer software, bibliometric mapping was carried out. The database search identified 150 articles, of which 54 contained information on the recycling of gypsum waste, with the participation of 163 authors from 24 countries, the most representative being Brazil, with 13 publications. In the end, there is a lack of publications related to the topic, and that, despite some works published in relevant journals, research related to gypsum waste ends up alienating researchers due to the lack of work that supports new research, since the reference theory is essential for defining research hypotheses.Item Acesso aberto (Open Access) Pressure regulation and energy recovery in water distribution networks using pumps as turbines(Associação Brasileira de Engenharia Sanitária e Ambiental, 2023-03) VIANA, Ingrid Luna Baia; BATISTA, Jamile Caroline Moreira; SÁ, João Henrique Macedo; RAMALHO, Rodolfo Vitorino Correia; LOPES, Raynner Menezes; SOUZA, Davi Edson Sales e; MESQUITA, André Luiz AmaranteWater distribution networks (WDNs) are considered a potential renewable energy source, as they have more than enough pressure energy to deliver water to users. To control excessive pressure, WDNs are commonly divided into district metered areas (DMAs) with pressure reducing valves (PRVs). The energy wasted by PRVs can be recovered using pumps as turbines (PATs). However, selecting the appropriate pump remains a challenge, as it must account for daily pressure and flow variations from consumers (off-design conditions). In this article, a combination of models was validated and applied to select the suitable pump for operating in an actual WDN. The replacement of two PRVs with PATs in a real network, previously divided into two DMAs and operating at constant speed was investigated. Economic and environmental analyses were also conducted. PAT1 was technically superior to PAT2 , as PAT2 exhibited negative outlet pressure, affecting the pressure in DMA2 . Optimal efficiencies are achieved at flow rates corresponding to the pump’s best efficiency point or near it, mimicking pressure control as if they were the valves themselves. The most efficient pump recovered 4,331 kWh/year, equivalent to a reduction of 1,732,400 gCO2/year, serving two households categorized as low income. PATs proved to be a viable alternative, with a payback period of 2.1 years, as it can recover renewable energy. However, for effective pressure control in WDNs, other operational strategies, such as variable speed operation, should be explored.Item Acesso aberto (Open Access) Análise do aproveitamento energético em redes de distribuição de água com a utilização de bombas como turbina (BFT)(Companhia de Saneamento Básico de São Paulo, 2023-09) SILVA, Victor Renan Barbosa da; ISHIHARA, Júnior Hiroyuki; VIANA, Ingrid Luna Baia; SOUSA, Juliana Melo de Sousa; SOUZA, Davi Edson Sales eWater distribution networks (WDNs) need adequate pressure to deliver water to users. In some cases, the pressure is excessive and is usually dissipated by pressure reducing valves (PRVs), which end up wasting this energy contained in the network. Due to the worldwide need to seek renewable energy generation technologies, researchers have studied the possibility of replacing these PRVs with a pump running as turbines (PAT). It is a centrifugal pump operating inversely in substitution of PRVs. As WDNs operate under varying conditions of flow and pressure, the prediction of PATs still encounters difficulties, which impairs their effective control of pressure when replacing PRVs. This work analyzes a real network with pressure management problems. Different locations of PRVs to control network pressure were proposed in two hydraulic simulations. The PRVs were replaced by PATs and it was evaluated to see which was the best configuration for greater control of supply pressure. The prediction of these machines was performed by a joint method that analyzes the entire operating range. In addition, the amount of energy recovered and the environmental benefits were estimated. The results show the pressure control in the two simulations (S1 and S2), in S1, the pressure in the most critical node was reduced in 42.80% and the energy recovery was 52 kWh/day. In S2, the pressure was reduced in 45.21% and the energy recovery was 190.96 kWh/day; in addition to better controlling the pressure, the energy recovery results were 267% higher than S1. The joint method, proposed in the research, simplified the PAT selection and prediction process, and it was possible to conclude that these machines should be installed in parallel with the PRVs, considering that, when the PATs cannot adjust the pressure at some times of the day, the valves do.Item Acesso aberto (Open Access) Predição de operação de bombas como turbina e sua aplicação para recuperação de energia em sistemas de distribuição de água(Universidad Nacional Autónoma de México, 2023-04) DUCATI, Juliana Gaia; SOUSA, Juliana Melo de; SOUSA, Davi Edson Sales e; MESQUITA, Andre Luiz AmarantePumps as turbines (PAT) are a sustainable alternative for generating energy by taking advantage of the hydraulic potential of a site. However, there are difficulties in predicting the turbine mode characteristic curves for off-design operating points, based on the curves provided by the pump manufacturers. The purpose of this work is to predict the PAT operating range of pumps selected to work as pressure-reducing valves (PRV) in the water supply system (WSS) of Vila Permanente, in Tucuruí - Pará, Brazil. Three experimental studies were evaluated for the prediction of head (Ht) and flow (Qt) of PATs in turbine mode at the best efficiency point (BEP). Then, a second method was applied that considers the entire operating range of PAT, combined with the methods in the BEP to obtain characteristic curves QxH (flow x head) and Qxη (flow x efficiency) of PAT. With the head and flow values of the pressure points in the WSS under study, centrifugal pumps were selected to work as turbines, applying the best combination of method and obtaining the characteristic curves of PAT in turbine mode, in order to obtain the operation range of the PAT, in addition to the calculations of partial energy recovery with values of 372.3 MWh/ year.Item Acesso aberto (Open Access) Influence of the supplementary reinforcement on the shear strength of beams with prefabricated truss stirrups(Instituto Brasileiro do Concreto, 2022) PINTO, Rosângela Silva; SOUSA, Vanessa Carolaine de; TAPAJÓS, Luamim Sales; FERREIRA, Maurício de Pina; LIMA NETO, Aarão FerreiraThis paper presents the results of seven experimental tests in reinforced concrete wide beams, aiming to investigate their performance when subjected to shear, using prefabricated truss stirrups as shear reinforcement, as well as a supplementary reinforcement to control cracks by delamination. The main analysed variables were: position of the supplementary reinforcement, inclination of the shear reinforcement, and spacing between stirrups. Results showed that strength increments of up to 142% were obtained using the prefabricated truss stirrups. Furthermore, the experimental results were compared with the theoretical shear strength estimates of the tested beams, following the recommendations of NBR 6118 (2014), Eurocode 2 (2004), and ACI 318 (2014), in order to evaluate the safety level of these codes when designing concrete elements subjected to shear with the reinforcement used in this paper.Item Acesso aberto (Open Access) Slabs strengthened for punching shear with post-installed steel and CFRP connectors(Universidade Federal do Pará, 2019-06) PEREIRA FILHO, Manoel José Mangabeira; FREITAS, Marcus Vinícius Pereira de; SANTOS, Douglas Freitas Augusto dos; FERREIRA, Maurício de Pina; NASCIMENTO, Alex J. C.Structural accidents due to punching shear failures have been reported in flat slab buildings. Design recommendations presented by codes can lead to entirely different punching shear resistance esti-mates for similar situations. Furthermore, design codes do not present guidelines for the design of punching shear strengthening of existing slabs. This paper uses a database with 118 experimental re-sults to discuss the performance of theoretical estimates of punching shear resistance using ACI 318, Eurocode 2 and ABNT NBR 6118 in the case of slabs without shear reinforcement. Another database with results of 62 tests on slabs strengthened with post-installed steel and CFRP dowels is used to evaluate the performance of these strengthening techniques and to propose adaptations in codes to allow their use in punching shear strengthening situations of existing slab-column connections.