Papers by Emanuel Negrão Macêdo
Journal of the Brazilian Society of Mechanical Sciences and Engineering
The great challenge in the field of combustion monitoring and fault diagnosis in diesel engines i... more The great challenge in the field of combustion monitoring and fault diagnosis in diesel engines is understanding the dynamic interactions that reveal the trajectory between the causes located in engine items and their effects or measurable symptoms to establish the rules that can generate diagnoses. In this context, the fault tree analysis (FTA) technique was applied to transform the engine and its subsystems into a structured logical diagram, in which were arranged the various combinations of failures in the engine component items that possibly may lead to undesirable events. With the set of diagnostic rules generated by the FTA serving as a knowledge base, inferences were made by an artificial neural network created to provide the operational condition of the engine submitted to tests. Despite the value errors and knowing that a perfect classification model must have values close to the expected values, it was very easy to distinguish the simulated operating conditions, which makes the diagnosis very consistent when compared with the expected results.
Numerical Heat Transfer, Part A: Applications
Journal of the Brazilian Society of Mechanical Sciences and Engineering
Conjeturas, Mar 30, 2022
As rochas ornamentais são bastante empregadas nos segmentos da construção civil, promovendo a int... more As rochas ornamentais são bastante empregadas nos segmentos da construção civil, promovendo a intensa exploração e extração das rochas minerais e, consequentemente, a geração de resíduos, causando diversos impactos ambientais e sociais. Deste modo, buscando uma empregabilidade para estes rejeitos, foram fabricados compósitos de matriz polimérica com carga de resíduo de mármore e granito nas granulometrias de 100, 200, 325 e 400 mesh da série de Tyler com o objetivo de verificar a influência das partículas nas propriedades mecânicas dos compósitos. A metodologia de produção baseou-se no método hand lay-up associado à prensagem em molde. A fase dispersa foi definida em fração mássica de 5, 10 e 15 %. As caracterizações do resíduo mostraram a presença de componentes como quartzo e dolomita e morfologia angular e a propriedade à tração revelou que a proporção de 5 % de resíduo apresentou, no geral, os melhores resultados, assim como as faixas de 100 e 200 meshs. Desta forma, tornando-os candidatos em certos tipos de aplicações, além de colaborar na minimização dos impactos ambientais.
Conjeturas, Mar 30, 2022
RESUMO A indústria de extração e corte de minerais descarta materiais que podem ser aproveitados ... more RESUMO A indústria de extração e corte de minerais descarta materiais que podem ser aproveitados e em busca de uma melhor destinação e diminuição dos impactos ambientais pesquisadores têm empregado esses rejeitos aliados a fibras vegetais na fabricação de novos materiais. Deste modo, foram produzidos compósitos de matriz polimérica com resíduo de mármore e granito na granulometria de 100 mesh da série Tyler e fibras de curauá no comprimento de 15 mm. O método de produção baseou-se no método hand lay-up associado à prensagem em molde. A fase dispersa foi definida em fração mássica de 5, 15 e 25 % de resíduo e proporção fixa de 3 % de fibras. A caracterização do resíduo apresentou grãos de tamanhos variados e angular e as fibras superfície rugosa e irregularidades. A caracterização física dos compósitos salientou o aumento e sensibilidade quanto sua proporção e a propriedade à tração revelou que a proporção de 5 % de resíduo e 3 % de fibras apresentou a melhor resposta. De tal maneira, os compósitos produzidos possibilitam a minimização dos impactos ambientais causados pelos rejeitos minerais e no incentivo de empregos ligados à zona rural por meio da comercialização das fibras.
The Minerals, Metals & Materials Series, 2018
The production of one ton of alumina using the Bayer process generates 0.7–2.0 ton of Bauxite Res... more The production of one ton of alumina using the Bayer process generates 0.7–2.0 ton of Bauxite Residue (BR) and an average of 1.0 ton of CO2. The direct use of exhaust gases to react and reduce the alkalinity of BR may allow a triple gain: improving the storage conditions, opening a range of new applications for BR and sequester from 16 to 102 kg of CO2 per ton of alumina. This paper shows a lab scale long term program to measure the effects of adding different percentages of Ca and Mg hydroxides followed by carbonation in order to enhance the precipitation of the alkalinity on stable compounds. Analysis by X-ray diffraction and scanning electron microscopy was done to monitor the appearance of carbonates. The BR pH was monitored for 600 days to evaluate the buffer effect and compared with the stabilization pH of carbonated bauxite residue without addition.
International Journal of Advanced Engineering Research and Science, 2018
In order to control the drying temperature of the PET resin in the silo of the plastic injection ... more In order to control the drying temperature of the PET resin in the silo of the plastic injection molding machine, during the plastic injection process in the industries producing preforms for the manufacture of beverage bottles, care is taken in the ideal temperature regulation for the better performance in controlling the generation of Acetaldehyde (AA), which alters the taste of carbonated or non-carbonated drinks, providing a citrus nuance to the palate and questioning the quality of the packaged products The objective of this work is to develop a tool based on Fuzzy logic to support the control of the drying temperature of PET resin, allowing specialists to make the ideal temperature control decisions necessary to control the generation of Acetaldehyde (AA). For the development of the proposed Fuzzy inference model, we used the Matlab Fuzzy toolbox tool, where the input variables, the fuzzyfication rules and the output variable were implemented based on the data collected from the preform injection process. From the inference model, we obtained a more precise management of the variables that influence the generation of AA, estimating a reduction of $ 240,044.00 in annual costs in the production of preforms.
International Journal of Numerical Methods for Heat & Fluid Flow, 2007
PurposeThis paper seeks to analyze transient convection‐diffusion by employing the generalized in... more PurposeThis paper seeks to analyze transient convection‐diffusion by employing the generalized integral transform technique (GITT) combined with an arbitrary transient filtering solution, aimed at enhancing the convergence behavior of the associated eigenfunction expansions. The idea is to consider analytical approximations of the original problem as filtering solutions, defined within specific ranges of the time variable, which act diminishing the importance of the source terms in the original formulation and yielding a filtered problem for which the integral transformation procedure results in faster converging eigenfunction expansions. An analytical local instantaneous filtering is then more closely considered to offer a hybrid numerical‐analytical solution scheme for linear or nonlinear convection‐diffusion problems.Design/methodology/approachThe approach is illustrated for a test‐case related to transient laminar convection within a parallel‐plates channel with axial diffusion ...
Journal of King Saud University - Science, 2017
The main goal of the present work is to show the procedure, application and main features of the ... more The main goal of the present work is to show the procedure, application and main features of the hybrid numerical-analytical approach known as GITT (Generalized Integral Transform Technique) by solving an unsteady, one-dimensional magnetohydrodynamic (MHD) oscillatory flow of a micropolar and incompressible fluid with heat and mass transfer through a permeable vertical plate embedded in a porous medium in the presence of chemical reaction. The mathematical formulation of the studied model was obtained from the equation of motion and the mass and energy balances by considering laminar and incompressible flow subjected to a constant transverse magnetic field with constant physical properties. Convergence analysis was performed and presented to illustrate the consistency of the integral transform technique. Linear and angular velocities distribution, temperature and concentration profiles were generated and numerically verified with an approximate solution found in the literature and with the results of the method of lines (MOL) with good agreement. The effects of some governing parameters, namely, dimensionless time, magnetic field parameter, Schmidt and Prandtl numbers, permeability and chemical reaction parameters, on these fields were presented. The effects of these parameters on the local skin friction coefficient, the couple stress coefficient, the local Nusselt number and the local Sherwood number were also critically evaluated. Therefore, results show that the linear velocity decreases with increasing magnetic field parameter, while the angular velocity increases with increasing the same and the linear and angular velocities and the concentration field decrease as the Schmidt number increases while the temperature field decreases with increasing Prandtl number.
Renewable Energy, 2016
This paper presents the development stages of a micro-scale system for electricity generation fro... more This paper presents the development stages of a micro-scale system for electricity generation from biomass with 500 W of power. The proposed system is based on an open steam power cycle, whose conception was aimed at seeking solutions to meet the needs for energy supply in isolated communities in the Amazon region. In addition the great biomass potential in the region is an opportunity for the application of biomass energy to increase the economic activity and develop new technologies. The tests performed demonstrate that the steam turbine is the critical component to the commercial-scale feasibility of the presented technology, particularly when it's proposed manufacturing of the system by small regional industries.
Materials Science Forum, 2010
This work has as objective the study experimental and computational of the hydrodynamics of gas-s... more This work has as objective the study experimental and computational of the hydrodynamics of gas-solid fluidized bed. The gas-solid fluidized beds present important applications in chemical industry; among typical examples of fluidized beds some applications could be outlined: the syntheses and catalytic reactions, the catalytic regeneration, the combustion and gasification of coal, coating, drying, etc. The simulated data were obtained through the commercial CFD (Computational fluid dynamics), and the results were compared to those obtained by experiments conducted in a fluidized bed, containing jambu seeds (Sphilantes oleracea L.) of 772.21 2.98 μm in diameter, sphericity de 0.45 0.0066, bulk density 1130.8 ± 0.22 Kg/m3 and with porosity 0.2303 0.0099. In this work the porosity profile and characteristic curve of fluidized bed were calculated by using an Eulerian multiphase model. The comparisons showed a very good agreement between experimental and simulation results.
Renewable Energy, 2011
This paper presents an analysis of the feasibility of implementing biomass power plants, through ... more This paper presents an analysis of the feasibility of implementing biomass power plants, through thermoelectric power generation, and adding such plants to the electric system of the local electric utility by means of independent power production. Economic, regulatory, and market issues are also addressed. The biomass being considered is produced by the lumber sector, since that is one of the industrial sectors generating the largest amount of residues in a concentrated manner in the region under study, and also considering the fact that the disposal of such residues is currently difficult for the lumber companies. The locations with the largest production of residues, as well as the size of potential plants, are identified, the generation costs of the plants calculated, and the feasibility for implementing the plants is evaluated considering the market and the regulation of the Brazilian electric power sector.
Proceedings of the 15th International Heat Transfer Conference, 2014
Hwang/Characterization, 2013
Renewable Energy, 2012
This paper presents a proposal of sustainable management model alternative for electrification of... more This paper presents a proposal of sustainable management model alternative for electrification of remote communities in the Amazon region, considering the Brazilian regulation policy. This paper presents also a case study of the electrification in a river-dwelling community in the State of Pará, Brazil, within the scope of the Program for Electric Power Service Universalization in Brazil. The community shall be provided with electrification facilities through a small biomass-based power plant, directly firing residues produced by the local economic activity. The objective of the paper is to make a proposal for a sustainable management model that is suitable for the community's isolation conditions, considering the high costs with operation and maintenance related to the supply for isolated consumers in small locations. A simulation is conducted for the operation of the small biomass-based power plant; the generation costs are determined; the legal aspects are analyzed; and a suggestion for the management model is presented.
Numerical Heat Transfer, Part A: Applications, 2007
... DOI: 10.1080/10407780701364445 SPA Paz a , EN Macêdo a , JNN Quaresma a & ... gen... more ... DOI: 10.1080/10407780701364445 SPA Paz a , EN Macêdo a , JNN Quaresma a & ... generality of purely numerical approaches for partial differential equations [11. WJ Minkowycz , EM Sparrow , and JY Murthy , Handbook of Numerical Heat Transfer, , 2d ed. , Wiley , New York ...
The Journal of Supercritical Fluids, 2014
ABSTRACT The main goal of this study was to assess the yield and the antimicrobial activity of ex... more ABSTRACT The main goal of this study was to assess the yield and the antimicrobial activity of extracts from Cyperus articulatus L. var. articulatus obtained by pressurized carbon dioxide based on their system phase diagram behavior. The extractions were carried out at 313, 323, 333 K temperatures and, 13 and 25 MPa pressures. The extracts were quantified and chemically characterized by using gas chromatography coupled to mass spectrometry technique. The extracts obtained at the following experimental conditions: 333 K and 13 MPa, showed antifungal activity against Cladosporium sphaerospermum ATCC 4464. At 323 K -25 MPa, and 333 K -25 MPa, the extracts showed antibacterial activity against Staphylococcus aureus ATCC 25923. To describe the kinetics of extraction with a packed bed, a mathematical model was employed highlighting the transference mechanisms for masses in the pseudo-binary system as follows (1) carbon dioxide and (2) priprioca extract, the monophasic and multiphasic regions.
JOM, 2010
... This paper shows that recycling residues can save money and reduce the overall impact of indu... more ... This paper shows that recycling residues can save money and reduce the overall impact of industrial processes, specifically in the ... Luis CA. Venancio, José Antonio Silva Souza, Emanuel Negrão Macedo, and João Nazareno N. Quaresma are at Federal University of Pará ...
International Journal of Heat and Mass Transfer, 2000
Abstract The Integral Transform Technique is used to solve the turbulent forced convection proble... more Abstract The Integral Transform Technique is used to solve the turbulent forced convection problem for drag-reducing fluids in the thermal developing and fully developed regions within circular tubes. Turbulent effects are taken into account through an algebraic model corresponding to the minimum-drag asymptotic case for viscoelastic fluids. The well-established Sign-Count Method and the Generalized Integral Transform Technique (GITT) are both employed in order to compute the eigenvalues and the respective eigenfunctions of the associated Sturm–Liouville problem. The Nusselt numbers calculated with the present approach are then compared with those obtained from experimental works available in the literature.
International Communications in Heat and Mass Transfer, 2000
The analysis of the mass transfer entry and fully-developed regions in turbulent flow of drag-red... more The analysis of the mass transfer entry and fully-developed regions in turbulent flow of drag-reducing viscoelastic fluids within circular tubes is performed in order to determine characteristics parameters to describe this related phenomenon. The mass diffusion equation is solved by the Classical Integral Transform Technique in conjunction with both the well-established Sign-Count Method and the so-called Generalized Integral Transform Technique (GITT) to solve the auxiliary eigenvalue problem. In light of these methodologies benchmark results for Sherwood numbers are systematically calculated for both regions studied, which are compared with previous others obtained from empirical correlation of current usage in the literature showing an excellent agreement.
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Papers by Emanuel Negrão Macêdo