Navegando por CNPq "CNPQ::ENGENHARIAS"

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Acesso aberto (Open Access)
Uma abordagem sistêmica para apoio à realização de diagnóstico inicial de avaliação do MPS.BR
(Universidade Federal do Pará, 2018-12-17) BRABO, Silvia Mariana Furtado; OLIVEIRA, Sandro Ronaldo Bezerra; http://lattes.cnpq.br/2080791630485427
Organizations that develop software in Brazil are investing more and more in improving their processes. At present, improvement initiatives are recurrent, with the MPS.BR model being an economically viable option for medium and small companies. Within this context, this master's dissertation presents a software tool to be used in the phase prior to an official evaluation of the MPS.BR model, in order to help the company to measure conformity compliance before an official evaluation and takes account the characteristics considered fundamental to the interpretation of the data made from articles, guides, manuals made available by SOFTEX regarding the model MPS.BR. The research seeks to understand the metrics used by the evaluators to define the completion of a task, to achieve the expected results and to apply automatic procedures capable of making the evaluated company aware of the next phase of the process. The tool has an intuitive and easy to use interface, it assists in a quantitative analysis of the MPS.BR model, which can help both the evaluator and the evaluated company to organize and make available the supporting documentation in an official MPS.BR evaluation. for software and enable the organization to use the tool during an evaluation, since the documentation to be evaluated would be organized within the system, leaving the evaluation process faster and possibly cheaper.
Acesso aberto (Open Access)
Aço inoxidável nanoestruturado produzido via soldagem a arco elétrico.
(Universidade Federal do Pará, 2021-07-08) LOAYZA, Cristhian Ricardo; BRAGA, Eduardo de Magalhães; http://lattes.cnpq.br/4783553888547500
Manufacturing methods of nanostructured stainless-steel composites (NSSC) have not yet been developed with industrial applicability. To overcome this shortage, the possibility of incorporating nanoparticles by electric arc welding was investigated, using a tubular rod filled with nanostructured flux composed of multi-walled carbon nanotubes (MWCNT) and 304L stainless steel particles. This flux was manufactured by two different methods: mechanical alloying (MA) and chemical treatment (CT) with hydrogen peroxide. The second showed more promising results using control of kinetic parameters of time and temperature, obtaining a lower degree of amorphous carbon, impurities, and crystalline defects, increasing their crystallinity and interaction of the nanotubes with the metallic matrix. MWCNT incorporation decreased the grain size by 64% when compared to the stainless-steel coating, possessing an austenitic matrix with carbide precipitation in the interdendritic spaces and grain boundaries. The microhardness increased 45% and the rate of erosion by vibratory cavitation decreased 64%, in relation to the AISI 304L coating. Additionally, XRD analyses showed a reduction of the γ{200} phase and a growth of γ{111} after the cavitation process. The method of manufacture of the nanocomposites proved to be economically viable and with the possibility of immediate application on a large scale.
Acesso aberto (Open Access)
Adsorção de cobre (II) presente em cachaça utilizando quitosana obtida por radiação micro-ondas: caracterização e estudo cinético
(Universidade Federal do Pará, 2020-02-27) SANTOS, Lucely Nogueira dos; FERREIRA, Nelson Rosa; http://lattes.cnpq.br/3482762086356570; https://orcid.org/0000-0001-6821-6199
Cachaça is a typical drink in Brazil and has been reaching more and more the national and international market. The cachaças produced in copper stills present unique characteristics, however they may be more susceptible to suffer contamination by copper (II). Adsorption by biopolymers has shown to be a very promising technique for the removal of metal ions. Chitosan is a biopolymer derived from the deacetylation of chitin and has free amino groups in its structure, which are strongly reactive to metal ions. Considering the aforementioned aspects, this work aimed to perform the deacetylation of chitosan using microwave irradiation technology and to evaluate the capacity of the chitosan obtained in adsorbing copper (II) from cachaça. Chitin was extracted from shrimp exoskeleton, chitosan was deacetylated and its adsorption capacity was evaluated through kinetic study using mathematical models. The copper (II) concentration remaining in the cachaça, in all kinetic experiments was estimated by the spectrophotometry technique in the visible region and confirmed by microwave-induced plasma optical emission spectrometry (MIP OES). Chitosan was characterized by infrared spectroscopy with attenuated reflectance (FTIR-ATR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and molecular mass The results of the characterization showed that the microwave deacetylation process it occurred efficiently, since the chitosan obtained had satisfactory properties in terms of its main characteristics observed, degree of deacetylation (above 85%), molecular weight, morphology and crystallinity. Regarding the adsorption kinetics, the best condition for copper adsorption was 6 mg of chitosan per mL of cachaça, in an equilibrium time of 60 min which resulted in a reduction rate of 84.09% of copper in the drink, according to results obtained by MIP OES. The kinetic analysis indicated the best fit of the data by the Elovich equation, suggesting that the chemisorption mechanism controls the kinetic process. Therefore, chitosan proved to be a good adsorbent for the removal of copper in cachaça and in this respect, a promising target for future technological investments.
Acesso aberto (Open Access)
Alcance da qualidade do produto a partir da qualidade do processo: análise da implementação integrada das práticas do CMMI-DEV com os resultados esperados do Certics
(Universidade Federal do Pará, 2018-12-17) SÁ, Marcelo Rocha de; OLIVEIRA, Sandro Ronaldo Bezerra; http://lattes.cnpq.br/2080791630485427
This dissertation addresses the aspects related to the search for software product quality certification from the implementation of software process maturity model in the context of a software company that in the development of one of its products obtained the CMMI-Dev 2 and started the respective CERTICS certification Describe the experience in the search for the certification of the PAGETO (Passive Agile Software Management Tool) product from the practices of CERTICS in line with the evaluation of the CMMI-DEV software process maturity. The results obtained relate to the identification of harmonization points between these two models and of complementary strategies and activities, in order to guarantee the overcoming of models divergences. These results were obtained from a peer review conducted with a specialist in the models involved in this research.
Acesso aberto (Open Access)
Análise da cobertura do solo usando NDVI, na região da hidrelétrica de Belo Monte, estado do Pará - Brasil
(Universidade Federal do Pará, 2019) CARRARO, Fábia Gabriela Pflugrath; FÜLBER, Heleno; http://lattes.cnpq.br/5018616409948511
The present work aims to analyze the ground cover, of the Belo Monte Dam complex region using NDVI (Normalized Difference Vegetation Index), calculated from TM / Landsat 5 and OLI / Landsat 8 images from 2008 to 2018. The use of images over the 10-year period can continuously identify trends in the pixels due to the change in land use. The mapping consisted of a polygon (buffer) on each side of the Xingu River, the images obtained during the dry period, in the Imaging Division of the United States Geological Survey (USGS). The scenes were processed and the thematic maps generated in ArcGIS® 10.2.2. and the NDVI tool was applied for the mapping of areas and then a grid was generated with the processed values, than the creation of thematic classes based on intervals of index values, for the generation of thematic images, with associated defined value intervals to a color scale. The reduction in NDVI values in the years 2008, 2009, 2016 and 2017 shows the direct influence of the decrease in vegetation due to deforestation. It is checked that during the time series, that from 2013 to 2016 there was a constancy in the NDVI values, indicating that in those years there were no major losses of plant biomass. Thus, the application of the index shows an efficiency when analyzing the behavior of the vegetation made it possible to verify a huge loss of plant biomass and increase of exposed soil due to the implantation of the Belo Monte Dam.
Acesso aberto (Open Access)
Análise da transferência de calor convectiva por transformada integral em canais com paredes onduladas
(Universidade Federal do Pará, 2019-12-13) MIYAGAWA, Helder Kiyoshi; QUARESMA, João Nazareno Nonato; http://lattes.cnpq.br/7826389991864785; https://orcid.org/0000-0001-9365-7498
The hybrid numerical-analytical approach known as the Generalized Integral Transformation Technique (GITT) is employed in the solution of the Navier-Stokes and energy equations that mathematically model the convective heat transfer in corrugated wall channels. The flow is considered laminar, incompressible, and two-dimensional involving a Newtonian fluid with temperature-independent physical properties, while wall temperatures are kept constant along the length of the channel. The streamfunction formulation is adopted, which eliminates the pressure field and automatically satisfies the continuity equation. Extensive convergence analyses are performed for the streamfunction and temperature fields, as well as for the product of friction factor by the Reynolds number and the local Nusselt number to demonstrate the robustness of the method. Verification of GITT results is also performed by comparing the centerline velocity, product of friction factor by the Reynolds number, average temperature, and local Nusselt number with those results obtained with the commercial COMSOL Multiphysics simulation software showing good agreement. The influence of parameters such as Reynolds number, wavy wall amplitude, number of waves, and phase between wall corrugations on the fields of velocity, temperature, and entropy generation are also analyzed, demonstrating their importance for convective heat transfer intensification and energy optimization.
Acesso aberto (Open Access)
Análise da variabilidade pluviométrica da região da UHE – Tucuruí/PA no período operacional (1988-2017)
(Universidade Federal do Pará, 2020-01-30) ALMEIDA, Denilson Freitas; ISHIHARA, Júnior Hiroyuki; http://lattes.cnpq.br/3498874642887006; https://orcid.org/0000-0002-0081-7913
The Tocantins - Araguaia hydrographic region has become a major power in the generation of hydraulic energy with the installation of large hydroelectric plants and the formation of several artificial lakes, resulting in hydrological changes and possible changes in the microclimate and rainfall. The analysis of rainfall behavior in the hydrographic basin becomes of fundamental importance for the management of water resources. In order to subsidize the management and planning of water resources in the region, an analysis of the spatial-temporal rainfall variability was carried out in the Lake HPP-Tucuruí / PA region, being divided into 4 quadrants (NE, NO , SO and SE) and 12 sub-areas (NE50, NE100, NE200, NO50, NO100, NO200, SO50, SO100, SO200, SE50, SE100 and SE200), considering the period of 30 years (1988-2017), in order to analyze the behavior of the rains in the region. To this end, data were collected and analyzed from 30 pluviometric stations that appear in the database of the ANA platform (HidroWeb base), within a radius of up to 200 km from the hydroelectric plant. With the aid of the QGIS 3.0.3 software, the isohyets maps were drawn using the linear ordinary kriging interpolation method, representing the heights of the water slides. The results showed variability in the spatial and temporal distribution of the total volume precipitated in the referred period of study, identified in the results of standard deviation and variance, in addition to the result of the trend of rains by Mann Kendall's non-parametric tests. The pluviometric indexes showed decreases, when analyzing the entire study area, with an average rainfall of 2157.73 mm. There was a greater decrease in precipitation in the southern part of the region, which showed lower rainfall. In the northern regions, where the artificial lake formed by the Tucuruí dam is found, there were higher rainfall averages. The Mann-Kendall (MK) results showed a greater decrease in the quadrants of the microscale (close to the bus), especially at NO50, which showed a significant trend of decreasing rainfall in the study region (Z = -2.24).
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 distorções e tensões residuais em painéis enrijecidos soldados com FCAW robotizado e CW-FCAW
(Universidade Federal do Pará, 2022-04-22) RODRIGUES, Lino Alberto Soares; BRAGA, Eduardo de Magalhães; http://lattes.cnpq.br/4783553888547500
Once the influence of welding imperfections in the form of distortions and residual stresses on the resistance of stiffened panels has been proven, monitoring the levels of these imperfections becomes a safety criterion, in view of the uncertainty of the real resistance losses of the panel, without having to measure the magnitudes of these welding imperfections. Thus, this work deals with the measurement of distortion levels and residual stresses by X-ray diffraction and ultrasonic birefringence in stiffened panels. First, the best of three welding sequences were selected using robotic FCAW welding. Sequence 03 showed distortion levels up to 10 times less and a residual stress level closer to neutrality (±100 MPa) compared to sequences 01 and 02. Then, using sequence 03, panels were welded using the CW-FCAW process with 40% cold wire and welding speeds of 100 m/min and 120 m/min. The results showed that the percentage of cold wire with high welding speeds did not reduce distortions, but influenced the level of residual stresses, leading to stresses closer to the neutral line (±100 MPa) on average.
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 alternativas intermodais para escoar a produção de soja dos Estados do Pará e Tocantins
(Universidade Federal do Pará, 2021-08-31) OLIVEIRA, Vitor Hugo Pereira de; ROCHA, Marcus Pinto da Costa da; http://lattes.cnpq.br/7169569605967930; TOBIAS, Maisa Sales Gama; http://lattes.cnpq.br/9635266655242384
World projections indicate an increase in demand for soy and, in this context, countries with continental dimensions and favorable soils such as Brazil stand out. Particularly, the states of the northern region of Brazil show themselves as possible new agricultural frontiers for this crop. However, they need to be competitive in order to sell their production, which indicates the need for studies of available modal alternatives to determine those with better economic results. With this in mind, the present work executed the analysis of alternative intermodal routes using linear programming, to identify the optimal solution route, in support to decision-making in the transport of soybeans for export, taking as a case a region located between States of Pará and Tocantins, close to the Araguaia-Tocantins waterway. Within the categories of linear programming models, the particular case called transport and transshipment problem was used. The model aimed to minimize transport costs from the production centers to the exporting port, through the current infrastructure and, under different scenarios of intermodal alternatives formed by the project of Ferrovia Paraense S.A. and by Araguaia-Tocantins waterway, the year 2019 and production projections are considered for the year 2029. The results showed that the scenarios with waterway transport bring greater benefit to the region, achieving savings of up to 23%. Furthermore, the Vila do Conde port complex expands its zone of influence, thus obtaining increase in the quantity exported in up to 1059.7%. As well, it confirms that the State of Pará is the one that most needs an intermodal alternative. Furthermore, the routes were configured in new transport networks, reducing the distances traveled in the road modal to transport production from the municipalities, reducing the flow on the main highways. Thus, it is concluded that intermodal transport improves regional competitiveness and favors the development of States.
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 de um vaso de pressão pós-incidente
(Universidade Federal do Pará, 2021-12-13) RODRIGUES, Igor Florentino; DIAS, Carmen Gilda Barroso Tavares; http://lattes.cnpq.br/2113791118142177
Composite materials have numerous applications in the most varied areas of engineering as offshore, oil and gas industry, marine industries, aeronautics, and automaker. Used because they bring high rigidity and specific resistance, due to the advantages of being resistant to corrosion and having structural flexibility. The work is focused on fiberglass composites with epoxy matrix (FG) and no high-density polyethylene (HDPE) a decade after the incident. The approach was based in two stage, first on an investigation that took place on board of a semisubmersible drilling rig that operates offshore with a drilling capacity of 7500 meters in depth and a water depth of 2500 meters. a high pressure line that is connected to CAPV (composite air pressure vessel) that is part of to the high pressure system of the CMC (Crown mounted compensator). In a second stage, was took samples from CAPV to be analyzed, where impact tests (Charpy) were performed according to ASTM D6110-10 standard, flexion tests according to ASTM D790-17 standard, differential scanning calorimetry (DSC) according to ASTM D3418-12 standard, scanning electron microscopy (SEM) and thermogravimetric to have a more detailed study on the composite materials that made up those vessels, which are PEHD and FG with matrix epoxy. Showed the results of the investigation and finish the work with material analyses assays even after 10 years of manufacture and complications during the use of the vessels.
Acesso aberto (Open Access)
Análise de viabilidade econômica da implantação de uma indústria beneficiadora de açaí no município de Abaetetuba/PA
(Universidade Federal do Pará, 2021-10-13) PRAXEDES, Adalberto Malato; CORREA, Alessandro de Castro; http://lattes.cnpq.br/6408989265441974
This work analyzed the economic feasibility of implementing an açaí processing industry in the city of Abaetetuba/PA. A structured interview was carried out with the interested investor group in order to understand their objectives and expectations, as well as the project's premises. The average cost of açaí in the harvest and in the off-season was estimated through a survey in the domestic market. The evaluation was carried out based on the discounted cash flow method, the Net Present Value, the Internal Rate of Return and Payback as feasibility indicators. For the Minimum Attractiveness Rate, the cost of capital was adopted based on the beta calculated by the Capital Asset Pricing Model (CAPM) from daily observations of share prices of companies in the Brazilian food sector from 04/01/2018 to 04/01 /2021 and the Selic rate as a risk-free rate. The Monte Carlo simulation technique was used to analyze the uncertainty associated with different scenarios resulting from variations in demand, in the cost of goods produced in the harvest, in the cost of goods produced in the off-season and in the sale price. The results indicated that the project is viable and suggest that there is a 62.82% chance of generating positive results.
Acesso aberto (Open Access)
Análise de vibrações mecânicas em estruturas esbeltas e flexíveis, como cordas e vigas, sujeitas à movimentação axial utilizando a técnica da transformada integral generalizada
(Universidade Federal do Pará, 2024-05-28) PORFÍRIO, Rogilson Nazaré da Silva; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505; QUARESMA, João Nazareno Nonato; http://lattes.cnpq.br/7826389991864785; https://orcid.org/0000-0001-9365-7498
The dynamic analysis of vibrations on flexible structures is of an extreme importance in engineering and its solution represents a significant challenge to be tackled. This study has the objective to investigate thin and flexible structures such as beams and ropes, that oscillate in supports clamped-clamped and clamped-concentrated mass, which determine the boundary conditions of the analysis problem. Using the generalized integral transformation technique (GITT) that converts the partial differential equation (PDE) developed by the Hamiltonian method in an Ordinary Differential Equation (ODE), it optimizes the numerical process andcontrols efficiently the relative error of the calculations. In this study, it was developed and applied an innovative method that treats the boundary conditions without the use of filters to homogenize the equations. The calculations methodology was implemented in Fortran, utilizing a sub-routine DIVPAG of IMSL. As reference, a thorough analysis of convergence and stableness was applied, considering the behavior of four different models of ropes and two models of beams. The validation of methodology was approached comparing functional aspects such as transversal displacement, system velocities, frequencies, and damping, with results obtained by GITT and other studies that applied the same simulation conditions. The results of this study were found to be satisfactory, which highlights the relevancy of application of this vibration analysis method. It was also assessed the application of this method in different vibration configurations in each model, which exemplifies its broad potential in problems involving the structures analyzed. Therefore, this study represents a significant contribution to the advance of knowledge in dynamic modeling of thin and flexible structures and highlights the influence of boundary conditions in vibrational characteristics of these structures.Furthermore, it introduces an innovative methodology for treating boundary conditions without the use of filters, expanding the analysis possibilities in this field of engineering.
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 do comportamento da precipitação e da vazão em bacias hidrográficas Amazônicas
(Universidade Federal do Pará, 2016-03-14) HACHEM, Bruno Penna; FERNANDES, Lindemberg Lima; http://lattes.cnpq.br/4641468846318922
The aim of this study was to analyze the behavior of precipitation and flow in two river regions of the state of Pará, where Northern Corridor and Coast Northeast Atlantic. Both have the same rainfall and physical properties of the bowls are similar, being different only in regard to level and vegetable preservation area. For this study, we used 7 gauged stations and 7 rainfall in the Northern Corridor and 6 fluviometric 6 and rainfall in Costa Northeast Atlantic. After collecting the data in HIDROWEB, they were organized in Microsoft Excel spreadsheets software for application of Mann Kendall and Spearman tests, which stated that there is no trend in the series analyzed (α=5%). Was detected that the density of fluviometric and rainfall stations is low , according to the thresholds established by WMO. The Pearson correlation coefficients showed up "strong" between precipitation and flow of the areas studied, which also suffer influence of climatic phenomena (El Niño and La Niña). It was possible to consider that in the most preserved region, the time lag between the maximum rainfall and the maximum flow rate averaged two months, while the region with greater human action this time was an average of 1 month.