Artigos Científicos - ITEC

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/3360

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Aforar, arrumar e alinhar: a atuação da Câmara Municipal de Belém na configuração urbano-fundiária da cidade durante o século XIX
(Universidade Federal do Pará, 2018-12-03) LIMA, José Júlio Ferreira; FISCHER, Luly Rodrigues da Cunha; ABREU, Paula Vanessa Luz de
The paper examines the morphological transformation of the city of Belém, influenced by the new land regime inaugurated by the Land Law of 1850 and by the growth of state urban planning. We investigate the actions of the City Council in the urban land tenure and the implementation of an Expansion Plan for Belém in the 19th century. In order to understand the spatial actions undertaken by the City Council, we started from the study of three instruments: emphyteusis, the main form of land transfer used by the City Council; alignment, related to the public-private boundaries and streets definitions; and land demarcation. We investigated the original land documents that record the emphyteusis, alignment and land demarcation carried out by the City Council along the Bragança Road, the main axis of city expansion in the 19th century. From the graphic spatialization of the information contained in these documents and the research in local newspapers, it was possible to verify that the City Council acted as a pioneer state agent, through a systematized land subdivision project. The discussion contributes to the comprehension of the structuring role of the local power in the definition and change of urban morphology and to a new understanding of the Belém Expansion Plan, classifying it as not only a urban beautification project, but as a product of the political-land tenure transition that marks the nineteenth century.
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An automatic methodology for obtaining optimum shape factors for the radial point interpolation method
(2011-12) MACHADO, Péricles Lopes; OLIVEIRA, Rodrigo Melo e Silva de; SOUZA, Washington César Braga de; ARAÚJO, Ramon Cristian Fernandes; TOSTES, Maria Emília de Lima; GONÇALVES, Cláudio
In this letter, a methodology is proposed for automatically (and locally) obtaining the shape factor c for the Gaussian basis functions, for each support domain, in order to increase numerical precision and mainly to avoid matrix inversion impossibilities. The concept of calibration function is introduced, which is used for obtaining c. The methodology developed was applied for a 2-D numerical experiment, which results are compared to analytical solution. This comparison revels that the results associated to the developed methodology are very close to the analytical solution for the entire bandwidth of the excitation pulse. The proposed methodology is called in this work Local Shape Factor Calibration Method (LSFCM).
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Análise da influência do formato de elemento de concreto e propriedades de fibras de aço na tenacidade à flexão
(Rede Latino-Americana de Materiais, 2018-10) OLIVEIRA, Marco Antonio Barbosa de; RAMOS, Edson Marcos Leal Soares; OLIVEIRA, Dênio Ramam Carvalho de; POMPEU NETO, Bernardo Borges
Concrete characterizing studies with steel fibers starting from the assay of the traction on flexural of prisms to obtain the toughness flexural have being done to the parameterization of the mechanic behavior of concrete pipes with steel fibers. The study aim is to adjust curves modeling the toughness estimates to the flex on concrete pipes in function to the toughness flexural on prims, both with steel fibers randomly oriented and moreover verify if there is or there is not significant statistic difference among toughness average to flexural when compared to the concrete element form (pipe or prism), and the priorities of steel fibers: Form Factor (65 or 80), State (free or joined to the basis comb) and theoretical fiber consumptions (0,25% or 0,38% or 0,50%). Curves were adjusted modeling the concrete pipe toughness with steel fibers in function of prism flexural toughness, being possible to observe that larger is the prism flexural toughness the larger will be the pipe flexural toughness. The analysis of variance was used to evaluate the existence or not of significant statistic difference among double or triple or quadruples associations. It was individually found that there is not significant statistic difference among the average values of toughness flexural, when compared concrete elements forms, however, there is significant statistic average values of toughness flexural when compared: (i) Form Factor; (ii) State and (iii) Theoretical Fiber Consumption. There was influence on the average values of flexural toughness when we make associations among the different levels of form factors, state and theoretical consumptions on fibers.
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Análise do potencial pozolânico da cinza de casca de arroz (CCA) através da técnica de refinamento de Rietveld
(2014-06) CORDEIRO, Luciana de Nazaré Pinheiro; MASUERO, Ângela Borges; DAL MOLIN, Denise Carpena Coitinho
Rice husk ash (RHA) is an agricultural by-product with well-known pozzolanic properties. However, the widespread commercial use of RHA is hindered by the lack of consistency between batches of this material and by the lack of quick and inexpensive quality control parameters. This study presents some basic principles for the quantification of the amorphous phases of RHA with the assumption that mineralogic characterization with X-ray diffraction can be a good quality control method for use residual or controlled ashes. The samples in this study were prepared with a lithium fluoride (LiF) standard and phase quantification was carried out using Rietveld's refinement method. The analysis of the phases was successfully conducted and results were satisfactory, with maximum relative standard deviation of 5%. These results show that quantitative analysis by Rietveld refinement can be used in the characterization of construction waste.
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Análise estatística do comportamento mecânico à compressão do compósito cimento-madeira
(2011) MACÊDO, Alcebíades Negrão; LIMA, Alexandre Martins de; FONSECA, Fábio de Oliveira; LAVÔR, Bárbara Valéria de Abreu
The present work has the objective to propose the use of saw dust wood waste from the tropical wood industry mainly located at Belém, Pará State, for the fabrication of wood-cement composites. Due to the natural chemical incompatibility between wood and cement, this procedure results in a set retarding effect, with wood specie depending intensity. This by-effect can be overcome by using procedures such as additives, wood mineralization, accelerated carbonation and others. Analysis were made based on axial compression strength data with samples aged 28 days for mortars made with 2, 3.5 and 5% wood content in mass, using cements type CP I and CP II, with and without Calcium Clorets-based set accelerator additive. The data there from obtained was statistically analyzed to evaluate the influence of the wood content and of additives on the mechanical strength. Most of the research works developed so far make use of reforestation waste, very little being available about tropical wood waste. So, this work represents a pioneer effort in developing a cement-bonded wood composite with regionally available materials and residues from Belém, Pará State.
Acesso aberto (Open Access)
Avaliação de processos de misturas de concretos com agregados graúdos reciclados
(Universidade Federal do Pará, 2017-09) CORDEIRO, Luciana de Nazaré Pinheiro; MASUERO, Ângela Borges; DAL MOLIN, Denise Carpena Coitinho; SOUZA, Paulo Sérgio Lima; PAES, Isaura Nazaré Lobato
The reuse of construction waste is a strategy employed to achieve sustainability, however, only a small number of construction initiatives use it. The variability of concrete residue is an inherent condition of this product and it must be considered. The control of the production process of concrete produced with concrete waste can improve the quality of the final composite. This paper aims to evaluate the effect of the mixing process and the mixer type on the fragility of recycled coarse aggregate concrete and to investigate their influence on compressive strength. This study also evaluates the effect of the mixer on concrete performance. Recycled coarse aggregate concrete was used as a total replacement for natural coarse aggregate. The results showed no significant differences between concrete produced from different types of mixtures, however, both yielded satisfactory compressive strength results at 28 days. However, the mixtures made in the vertical shaft mixer were more efficient than the mixtures produced in the inclined axis mixer, as the concrete produced by the former presented a lower variation coefficient. The study concluded that the equipment's characteristics contributed to better uniformity, leading to less variability in the resulting concrete.
Acesso aberto (Open Access)
Avaliação do comportamento reológica e mecânico de geopolímero sintetizado com reaproveitamento de resíduo
(Rede Latino-Americana de Materiais, 2018-10) BRITO, Woshington da Silva; BRUM, Sebastião Martins; SILVA, André Luis Mileo Ferraioli; FELIPE, Augusta Maria Paulain Ferreira; SOUZA, José Antônio da Silva
The sustainable construction of the future, besides low energy consumption and greenhouse gas emissions must also adopt the principle of reusing wastes generated by the production chain that impact the environment. One of the most impacting wastes generated by the aluminum production chain is fly ash. Geopolymers are cementitious materials with a three-dimensional structure formed by chemical activation of aluminosilicates. According to studies some ashes have proven to be suitable sources of Al and Si for the geopolymerization reaction. One of the most important aspects in the commercializing these products is their behavior in a plastic state. The workability of fresh geopolymer paste can be measured using several common tests used for Portland cement concrete, such as flow and slump; however, a more in-depth characterization of their rheology is essential for understanding their basic setting mechanisms. The objective of this work was to evaluate the rheological behavior of the Davidovits (SiO2/Al2O3) geopolymer paste at 2.65; 3.04 and 4.11. The mechanical resistance to compression at 24 hours, 7 days and 28 days of geopolymer cure was also evaluated. The geopolymerization reaction was conducted at ambient temperature of 28°C and 15 Molar sodium hydroxide (NaOH) and 10 Molar sodium silicate (Na2SiO3), were used as the activator. Fly ash and metakaolin were used as source of Al and Si was used. XRD, XRF, SEM techniques were used in the characterization of raw materials and geopolymers. The geopolymer with a lower Davidovits ratio of 2.65 presented better workability in its fresh state and higher mechanical strength at 40.80 MPa compression with 28 days cure at ambient temperature. The Herchel Bulkley rheological model was the one that was best adjusted to the geopolymers.
Acesso aberto (Open Access)
Canaã dos Carajás: um laboratório sobre as circunstâncias da urbanização, na periferia global e no alvorecer do século XXI
(Associação Nacional de Pós-Graduação e Pesquisa em Planejamento Urbano e Regional, 2018-04) CARDOSO, Ana Cláudia Duarte; CÂNDIDO, Lucas Souto; MELO, Ana Carolina Campos de
This article addresses the processes of urbanization and urban sprawl in Canaã dos Carajás, a small relatively recent Amazonian municipality. The analysis is dialectically structured according to Lefebvre’s interpretation of the levels of social reality. The global level captures how capitalintensive activities (mining, ranching, and monoculture) have impacted the connection between the place of production and the global market. The mixed level explains how local social groups, inspired by global processes, have mediated urbanization. The local level demonstrates how blind spots in understanding the ongoing processes have impaired the strengthening of diversity, and led to the exclusion of social groups that most depend on the land and nature. We conclude that it is necessary to articulate contemporary formulations and studies on Brazilian urbanization so as to demonstrate the selective manner in which modernization takes place and is constituted in new forms of colonization, whenever economic opportunities formulate socioenvironmental issues in a conservative manner.
Acesso aberto (Open Access)
Caracterização completa da madeira da espécie amazônica Paricá (Schizolobium amazonicum Herb) em peças de dimensões estruturais
(2013-12) ALMEIDA, Diego Henrique de; SCALIANTE, Ricardo de Mello; MACEDO, Laurenn Borges de; MACÊDO, Alcebíades Negrão; DIAS, Antonio Alves; CHRISTOFORO, André Luis; CALIL JUNIOR, Carlito
The Amazon specie Paricá (Schizolobium amazonicum Herb) present fasts growth and very good development in diameter in a few years, a small amount of nodes and defects, key characteristic in its use for structural purpose. The aim of this paper was to determine the strength and stiffness properties of Paricá wood, according to ABNT NBR 7190: 2011, as well, perform the visual classification of members for determination of defects as: nodes, inclination of grain, warpings. The concluding that the Paricá wood is classified as C 20 dicotyledonous class, low density, with good compression strength parallel to the grain, with a great potential to be used in civil construction, when compared with other species and, in relation to the visual analysis, few nodes, right grain and has no warping.
Acesso aberto (Open Access)
Chemical composition of different muscle zones in pirarucu (Arapaima gigas)
(Universidade Federal do Pará, 2017-04) MARTINS, Mayara Galvão; MARTINS, Déborah Elena Galvão; PENA, Rosinelson da Silva
Identifying potential patterns in pirarucu (Arapaima gigas) composition, as a function of the different fish muscle zones (dorse, venter, ventrecha and tail), was the main objective of this research. For such, the different pirarucu muscle zones were evaluated, in order to obtain proximate composition and minerals content. It was also determined amino acids and fatty acids contents in fish muscle. The dorsal, ventral and tail muscle zones presented similar moisture (76.5-78.2%), protein (17.8-18.9%), total lipids (1.0-1.5%) and ash (0.9-1.2%) contents. On the other hand, the ventrecha zone presented 25.8% of protein and the major total lipids content (17.1%). The main minerals found in fish muscle were K (183.5-288.6 mg/100 g muscle) and Na (65.1-175.5 mg/100 g). Glutamic acid (3027.6 mg/100 g muscle) was the main amino acid found in fish muscle, which presented 48% of essential amino acids in the protein fraction. Lipids content showed 57.3% of unsaturated fatty acids and 42.7% of saturated fatty acids.
Acesso aberto (Open Access)
Comparative study on the quality of oil extracted from two tucumã varieties using supercritical carbon dioxide
(Universidade Federal do Pará, 2016-06) COSTA, Bárbara Elizabeth Teixeira; SANTOS, Orquídea Vasconcelos dos; CORRÊA, Nádia Cristina Fernandes; FRANÇA, Luiz Ferreira de
The vast Amazon region has considerable territorial peculiarities and plant species diversity, sometimes from the same botanical family, which can exhibit significant differences in physicochemical properties. From this diversity, two species stand out – Amazonas tucumã (Astrocaryum aculeatum Meyer) and Pará tucumã (Astrocaryum vulgare Mart.). The research focus is to analyze, comparatively, these oleaginous fruits, their similarities, particularities and potentials regarding the oil quality extracted from two tucumã varieties from the states of Amazonas and Pará, obtained using supercritical carbon dioxide, under different extraction parameters. The results demonstrate the biometric particularities of each species, highlighting the Amazon fruit, which also showed higher oil yield using supercritical CO2 extraction. The fatty acid quality and profile aspects of the oils show their unsaturated predominance, considering carotenoid content and how the extraction temperature can influence the nutritional quality of the oils. The statistical analyses indicated that the Amazon tucumã oil is superior to the Pará tucumã oil. However, in terms of added value both oils have potential applications in various industrial segments.
Acesso aberto (Open Access)
Comparison of the effects of brazil nut oil and soybean oil on the cardiometabolic parameters of patients with metabolic syndrome: a randomized trial
(Multidisciplinary Digital Publishing Institute, 2020) SILVA, Lívia Martins Costa e; MELO, Maria Luisa Pereira de; REIS, Fernando Vinícius Faro; MONTEIRO, Marta Chagas; SANTOS, Sávio Monteiro dos; GOMES, Bruno Alexandre Quadros; SILVA, Luiza Helena Meller da
Recent evidence suggests that replacing saturated fat with unsaturated fat is beneficial for cardiovascular health. This study compared the effects of Brazil nut oil (BNO) and soybean oil (SO) supplementation for 30 days on anthropometric, blood pressure, biochemical, and oxidative parameters in patients with metabolic syndrome (MS). Thirty-one patients with MS were randomly allocated to receive 30 sachets with 10 mL each of either BNO (n = 15) or SO (n = 16) for daily supplementation. Variables were measured at the beginning of the study and after 30 days of intervention. No change in anthropometric and blood pressure variables were observed (p > 0.05). Total (p = 0.0253) and low-density lipoprotein (p = 0.0437) cholesterol increased in the SO group. High-density lipoprotein cholesterol decreased (p = 0.0087) and triglycerides increased (p = 0.0045) in the BNO group. Malondialdehyde levels decreased in the BNO group (p = 0.0296) and total antioxidant capacity improved in the SO group (p = 0.0110). Although the addition of oils without lifestyle interventions did not affect anthropometric findings or blood pressure and promoted undesirable results in the lipid profile in both groups, daily supplementation of BNO for 30 days decreased lipid peroxidation, contributing to oxidative stress reduction.
Acesso aberto (Open Access)
Comportamento reológico de suco misto elaborado com frutas tropicais
(2013-06) BEZERRA, Carolina Vieira; SILVA, Luiza Helena Meller da; COSTA, Rebeca Desireé Sousa da; MATTIETTO, Rafaella de Andrade; RODRIGUES, Antonio Manoel da Cruz
The rheological properties of a juice blend obtained from a tropical fruit mix were determined in this work using a rotational viscosimeter at temperatures from 10 ºC to 60 ºC. The Power law and Mizrahi-Berk models were fitted to the experimental data. All the models were considered adequate to describe the rheological properties of the juice blend according to the fitted statistical parameters. The behaviour index of the product was below 1.0, indicating the pseudoplasticity of the juice. The behaviour indexes for consistency were found to decrease with increase in temperature. The effect of temperature on the rheological behaviour of the juice was described by an Arrhenius type equation and discussed in terms of the activation energy (Ea). The values for Ea varied from 4.27 to 4.66 kcal.gmol-1 with increases in shear rate.
Acesso aberto (Open Access)
Construction delays: a case study in the Brazilian Amazon
(Universidade Federal do Pará, 2017-09) MAUÉS, Luiz Mauricio Furtado; SANTANA, Wylliam Bessa; SANTOS, Paulo Cerqueira dos; NEVES, Renato Martins das; DUARTE, André Augusto Azevedo Montenegro
The construction industry is one of the industrial sectors with the lowest rates of fulfilment of contract deadlines, especially in developing countries. This fact has been the focus of considerable discussions seeking to identify the causes of the delays. The main purpose of this paper is to use factor analysis to identify the factors that are correlated with delay, contemplating exclusively residential real estate projects and using a city in the Brazilian Amazon as a case study. Based on the database from the government agency that authorises constructions in the city of Belém (City Planning Department - Secretaria Municipal de Urbanismo, SEURB) and data from construction companies, the study investigated 274 construction projects from the past 11 years. Factor analysis and work with the variables that can be identified and measured in the initial phase of the project, i.e., during the feasibility study, demonstrate that the physical characteristics of the apartments and the construction project are the primary causes for variations in construction delays; these causes have not yet been reported in the literature. We hope that the results of this study will contribute to more consistent forecasting of construction time, minimising the risk of delays.
Acesso aberto (Open Access)
Corrosão em estacas metálicas de torres de energia elétrica
(Rede Latino-Americana de Materiais, 2019-05) VILHENA, Alexandre Evangelista Rodrigues; PINTO, Renata Godinho; COSTA, Rafaela Reis da; PICANÇO, Marcelo de Souza; MACÊDO, Alcebíades Negrão
In order to maintain the quality and continuity of the power supply it is essential to monitor the integrity of the structure of the transmission towers usually executed in steel. This study evaluated soil corrosivity in the Amazon region in the Vila do Conde-Tucuruí stretch, state of Pará. The resistivity, potential soil structure, redox potential, pH, chloride, sulphate and sulfate concentration, besides the Steinrath index and the quantification of the soil corrosivity through the installation of test specimens in the studied soil. The data were collected in the dry and rainy period while the specimens were removed after 12 months of exposure. The soils of the region presented resistivity higher than 20 kΩ.cm, characterizing as few corrosives; the redox potential of 100 to 300 mV indicated mild to moderately corrosive soils; the potential soil structure remained in the range of -0.4 to -0.7 V/ECS being within the range considered normal; the Steinrath index classified the soils into little corrosive to non-corrosive and the corrosion rates of the test specimens indicated high corrosion at 3 meters depth. Based on the results of each evaluation method used it can be verified that the soil corrosivity increases with the depth, besides being favorable to the attack of microbiological corrosion.
Acesso aberto (Open Access)
Dependência de recursos e custos de transação: rumo a um modelo convergente
(Universidade Federal do Pará, 2017-12) LOPES, Arleson Eduardo Monte Palma
The present study addresses the process of inter-organizational relationships from two theoretical perspectives: resource dependence and transaction costs. First, the text presents a bibliographic review on the two theoretical constructs; next, it discusses how the use of these theories can contribute to understanding the interorganizational phenomenon. Despite the divergence between the two perspectives, the authors conclude that they are convergent based on the bibliographic review. The convergence of these conceptions relates to the fact that organizational relations are a key factor for the functioning of companies. The resource dependence perspective suggests that resources are distributed in the environment and that firms develop organizational relationships to obtain them; in contrast, the perspective of transaction costs refers to the relations of economic exchange between organizations. Therefore, it is necessary to consider the assumptions of these two theoretical perspectives to understand inter-organizational relationships
Acesso aberto (Open Access)
Diversity of yeasts during fermentation of cocoa from two sites in the Brazilian Amazon
(Instituto Nacional de Pesquisas da Amazônia, 2019-03) ALMEIDA, Silvana de Fátima Oliveira de; SILVA, Letícia Ribeiro Carvalho; GHAGAS JUNIOR, Gilson Celso Albuquerque; OLIVEIRA, Guilherme; SILVA, Silvia Helena Marques da; VASCONCELOS JUNIOR, Santelmo Selmo de Vasconcelos; LOPES, Alessandra Santos
The purpose of this study was to identify the yeasts involved in spontaneous fermentation of cocoa from the Brazilian Amazon region. The fermentation process was carried out experimentally with cocoa seeds from two sites (Medicilândia and Tucumã), State of Pará, northern Brazil, during a six-day period. Totals of 44 yeasts were isolated from Medicilândia and 29 from Tucumã. Molecular identification was carried out by sequencing the D1/D2 region fragment of the rRNA 26S gene, expanded with universal primers for the NL1GC and LS2 eukaryotes. Pichia manshurica and Saccharomyces cerevisiae were identified in Medicilândia and five yeast species (Pichia fermentans, P. kudriavzevii, P. manshurica, S. cerevisiae and Zygosaccharomyces bailii) were identified in Tucumã. The results showed that P. manshurica and S. cerevisiae may have potential for use as starter cultures in future studies to improve the quality of cocoa seeds fermented in the Brazilian Amazon region.
Acesso aberto (Open Access)
Efeito de aditivos no comportamento reológico do rejeito da bauxita
(Universidade Federal do Pará, 2015-03) GONÇALVES, Silvane Gonçalves e; BRUM, Sebastião Martins; FELIPE, Augusta Maria Paulain Ferreira; SOUZA, José Antônio da Silva; FERREIRA, Keylla Castro
In the bauxite mining in Parogominas, PA, Brazil, tailings are discarded in the processing with 33.5% of solids content and small particle size with D50 below 5 µm. These factors contribute to this suspension basically formed by silicoaluminates, with high concentrations of kaolinite clay, increase the viscosity and the yield stress, these factors are important during the pumping. It was performed granulometric analysis and determined the chemical and mineralogical composition of the material. It was studied the use of the sodium hexametaphosphate and polyacrylamide 25% anionic to decrease the viscosity. The result show that the viscosity decrease with use of 23.8 g/ton for the polyacrylamide and 101.75 g/ton for the sodium hexametaphosphate. The particle size and the pH have influence in the behavior of the additives.
Acesso aberto (Open Access)
Effect of the T6 Heat Treatment on Microhardness of a Directionally Solidified Aluminum-Based 319 Alloy
(Universidade Federal do Pará, 2017-11) MAGNO, Igor Alexsander Barbosa; SOUZA, Fabricio Vinicius Andrade de; BARROS, André dos Santos; COSTA, Marlo Oliveira; NASCIMENTO, Jacson Malcher; COSTA, Thiago Antônio Paixão de Sousa; ROCHA, Otávio Fernandes Lima da
Aluminum alloys of the ANSI series 319 present Si and Cu as the main alloying elements and the mechanical strength of these alloys can be improved by the precipitation of the metastable Al2Cu phase during the ageing heat treatment. In this paper, the Al-5.5wt.%Si-3wt.%Cu alloy was elaborated and solidified in a water-cooled horizontal directional solidification device. The as-cast ingot was subjected to the precipitation hardening heat treatment (T6 heat treatment), which consisted of: solution for 5 h at 490°C±2°C, followed by quenching in water at 60°C±2°C and ageing for 3 h at 155°C±2°C, and cooling-air. Secondary dendrite arm spacing (λ2) measurements were carried out before and after T6 heat treatment. The mechanical strength of the alloy was investigated by the microhardness test. It has been found that the heat treatment did not influence the λ2 values, however, highest HV values have been observed for the heat-treated samples.
Acesso aberto (Open Access)
Effect of wind in the design of reinforced concrete buildings
(Universidade Federal do Pará, 2016-12) TAPAJOS, Luamim Sales; FERREIRA, José Augusto Tavares; LIMA NETO, Aarão Ferreira; TEIXEIRA, Marcelo Rassy; FERREIRA, Maurício de Pina
This paper presents the results from a parametric study carried in order to quantify how far errors in the design stage related to the consideration of the wind action may put at risk the response and safety of reinforced concrete buildings. Using an architectural model as reference and varying the number of floors of the building, the structural safety was evaluated as a function of the wind action intensity. Results showed that even for low-rise buildings, with 10 floors, ignoring the wind action can significantly jeopardize their behaviour and safety. Yet, for slenderer buildings, up to 30 floors, it can lead to catastrophic results, as the ruin of the structure by progressive collapse.