Centro Integrado Of Manufatura E Tecnologia
Centro Integrado Of Manufatura E Tecnologia
Feroni R.D.C.,Federal University of Espirito Santo |
Reis Junior N.C.,Federal University of Espirito Santo |
Santos J.M.,Federal University of Espirito Santo |
Moreira D.,Centro Integrado Of Manufatura E Tecnologia
Journal of Turbulence | Year: 2017
A multiphase study was conducted using a turbulence model of large eddy simulation to investigate the interaction between the gaseous phase and the interface and its respective behaviour until the liquid phase movement was established, first in the near interface, as well as the presence of turbulent structures in the study of transport between phases. The results are shown for three surface configurations: a surface with waves in which the Reynolds number and friction velocity of the gaseous phase are, respectively, 210 and 0.25 m/s; a surface with small undulations, 86 and 0.10 m/s; and a flat surface, 43 and 0.05 m/s. Coherent structures are detected on both sides of the interface; these are intensified and less elongated for larger Reynolds numbers. Additionally, the interface exhibits distinct behaviour with regard to the examined phases. For the gaseous phase, it behaves like a no-slip surface. © 2017 Informa UK Limited, trading as Taylor & Francis Group
Rosario F.,Federal University of Santa Catarina |
Pachekoski W.M.,Centro Integrado Of Manufatura E Tecnologia |
Dos Santos S.F.,University of Sao Paulo |
Junior H.S.,University of Sao Paulo |
Casarin S.A.,Federal University of São Carlos
Polimeros | Year: 2011
The mechanical and thermal properties of virgin and recycled polypropylene composites reinforced with 30% by mass of residual sisal fibers were studied, in addition to an analysis of the extrusion process and morphology of the polymeric matrix. Tensile strength, Young's modulus, elongation at break, and impact energy were determined. The samples were also characterized by SEM, DMTA and TG analyses. Elongation at break of the composites presented a significant decrease, while the tensile strength was not affected significantly by addition of sisal fibers. A significant increase was observed in the tension of rupture and in the impact energy of the composite reinforced with sisal fiber. The thermal analyses indicated secondary interactions, such as polar interactions, between the fibers and the matrix, consistent with the mechanical behavior of the composites. The glass transition temperature has not changed after fiber addition.
Mendonca L.R.,Federal University of Bahia |
Figueiredo C.A.,Federal University of Bahia |
Esquivel R.,Centro Integrado Of Manufatura E Tecnologia |
Fiaccone R.L.,Federal University of Bahia |
And 5 more authors.
Acta Tropica | Year: 2013
Objectives: This study aimed to standardize an "in house" immunoassay to detect anti-. Toxocara IgG antibodies in human serum to estimate the seroprevalence of Toxocara infection, and to identify its potential risk factors in children living in poor areas of Salvador, a large northeastern Brazilian city. Methods: Parents of 1309 children answered a questionnaire containing possible risk factor for acquisition of this infection. Blood was collected and the presence of anti-. Toxocara IgG antibodies was detected by indirect ELISA using T. canis larval excretory-secretory antigens in sera previously absorbed with Ascaris lumbricoides antigens. Results: Seroprevalence of Toxocara infection was 48.4%. Children's age, low maternal schooling, contact with dogs and cats, and household located in paved streets were shown to be risk factors for Toxocara infection. Conclusions: The seroprevalence of Toxocara infection is high among children living in a poor urban setting of Brazil. The association of low maternal education with higher Toxocara infection supports studies showing that low socioeconomic status is a risk factor for the acquisition of this infection as a reflection of hygiene habits of the family. And both infected-dogs and cats may be involved in this parasite transmission in this children population. © 2013 Elsevier B.V.
Santos L.O.,Federal University of Bahia |
dos Anjos J.P.,Federal University of Bahia |
dos Anjos J.P.,Centro Integrado Of Manufatura E Tecnologia |
Ferreira S.L.C.,Federal University of Bahia |
de Andrade J.B.,Federal University of Bahia
Microchemical Journal | Year: 2017
Environmental contamination by PAHs and their derivatives can cause damage to human health due to the carcinogenic and mutagenic potential of these compounds. This work proposes a new method for simultaneous determination of PAHs, nitro-PAHs and quinones in surface and groundwater samples employing gas chromatography coupled to mass spectrometry (GC–MS) after single-drop microextraction (SDME). The extraction step using SDME was optimized and it was found that the best experimental conditions for 10 mL samples are: drop volume of 1.0 μL, toluene as extraction solvent, and stirring time of 30 min at 200 rpm. The limits of detection obtained were from 0.01 to 0.03 μg L− 1 for PAHs, from 0.26 to 1.07 μg L− 1 for nitro-PAHs and from 6.96 to 468 μg L− 1 for quinones. The limits of quantification obtained were from 0.05 to 0.09 μg L− 1 for PAHs, from 1.24 to 4.31 μg L− 1 for nitro-PAHs and from 23.2 to 1559 μg L− 1 for quinones. For intraday precision, the maximum value obtained for RSD was 19% and for interday precision was 18.7%. The accuracy was verified using addition/recovery tests and the recoveries achieved varied from 36% to 152% for PAHs, from 23% to 103% for nitro-PAHs and from 48% to 134% for quinones. Eight PAHs, six nitro-PAHs and two quinones were detected and quantified in surface and groundwater samples. The average concentrations obtained were 0.70 μg L− 1 (naphthalene) for PAHs, 1605 μg L− 1 (1,2-naphthoquinone) for quinones and 5.61 μg L− 1 (1-nitropyrene) for nitro-PAHs. Indeed, the proposed method showed good sensitivity, linearity, precision and accuracy for the determination of PAHs, nitro-PAHs and quinones in water samples. © 2017 Elsevier B.V.
Queiroz F.A.A.,Parque Tecnologico de Belo Horizonte |
Vieira D.A.G.,Parque Tecnologico de Belo Horizonte |
Travassos X.L.,Centro Integrado Of Manufatura E Tecnologia |
Pantoja M.F.,University of Granada
Mathematical Problems in Engineering | Year: 2012
This paper describes some efforts to design more efficient analysis for the GPR raw-data interpretation. Such analysis requires algorithms by which problems having complex scattering properties can be solved as accurately and as quickly as possible. This specification is difficult to achieve when dealing with iteratively solved algorithms characterized by a forward solver as part of the loop, which often makes the solution process computationally prohibitive for large problems. The inverse problem is solved by an alternative approach which uses model-free methods based on example data. Measurements with GPR equipment were performed to validate the algorithms using concrete slabs. © 2012 F. A. A. Queiroz et al.
Da Rocha G.O.,Federal University of Bahia |
De Andrade J.B.,Federal University of Bahia |
Guarieiro A.L.N.,Federal University of Bahia |
Guarieiro L.L.N.,Federal University of Bahia |
And 3 more authors.
Quimica Nova | Year: 2013
Coal, natural gas and petroleum-based liquid fuels are still the most widely used energy sources in modern society. The current scenario contrasts with the foreseen shortage of petroleum that was spread out in the beginning of the XXI century, when the concept of "energy security" emerged as an urgent agenda to ensure a good balance between energy supply and demand. Much beyond protecting refineries and oil ducts from terrorist attacks, these issues soon developed to a portfolio of measures related to process sustainability, involving at least three fundamental dimensions: (a) the need for technological breakthroughs to improve energy production worldwide; (b) the improvement of energy efficiency in all sectors of modern society; and (c) the increase of the social perception that education is a key-word towards a better use of our energy resources. Together with these technological, economic or social issues, "energy security" is also strongly influenced by environmental issues involving greenhouse gas emissions, loss of biodiversity in environmentally sensitive areas, pollution and poor solid waste management. For these and other reasons, the implementation of more sustainable practices in our currently available industrial facilities and the search for alternative energy sources that could partly replace the fossil fuels became a major priority throughout the world. Regarding fossil fuels, the main technological bottlenecks are related to the exploitation of less accessible petroleum resources such as those in the pre-salt layer, ranging from the proper characterization of these deep-water oil reservoirs, the development of lighter and more efficient equipment for both exploration and exploitation, the optimization of the drilling techniques, the achievement of further improvements in production yields and the establishment of specialized training programs for the technical staff. The production of natural gas from shale is also emerging in several countries but its production in large scale has several problems ranging from the unavoidable environmental impact of shale mining as well as to the bad consequences of its large scale exploitation in the past. The large scale use of coal has similar environmental problems, which are aggravated by difficulties in its proper characterization. Also, the mitigation of harmful gases and particulate matter that are released as a result of combustion is still depending on the development of new gas cleaning technologies including more efficient catalysts to improve its emission profile. On the other hand, biofuels are still struggling to fulfill their role in reducing our high dependence on fossil fuels. Fatty acid alkyl esters (biodiesel) from vegetable oils and ethanol from cane sucrose and corn starch are mature technologies whose market share is partially limited by the availability of their raw materials. For this reason, there has been a great effort to develop "second-generation" technologies to produce methanol, ethanol, butanol, biodiesel, biogas (methane), bio-oils, syngas and synthetic fuels from lower grade renewable feedstocks such as lignocellulosic materials whose consumption would not interfere with the rather sensitive issues of food security. Advanced fermentation processes are envisaged as "third generation" technologies and these are primarily linked to the use of algae feedstocks as well as other organisms that could produce biofuels or simply provide microbial biomass for the processes listed above. Due to the complexity and cost of their production chain, "third generation" technologies usually aim at high value added biofuels such as biojet fuel, biohydrogen and hydrocarbons with a fuel performance similar to diesel or gasoline, situations in which the use of genetically modified organisms is usually required. In general, the main challenges in this field could be summarized as follows: (a) the need for prospecting alternative sources of biomass that are not linked to the food chain; (b) the intensive use of green chemistry principles in our current industrial activities; (c) the development of mature technologies for the production of second and third generation biofuels; (d) the development of safe bioprocesses that are based on environmentally benign microorganisms; (e) the scale-up of potential technologies to a suitable demonstration scale; and (f) the full understanding of the technological and environmental implications of the food vs. fuel debate. On the basis of these, the main objective of this article is to stimulate the discussion and help the decision making regarding "energy security" issues and their challenges for modern society, in such a way to encourage the participation of the Brazilian Chemistry community in the design of a road map for a safer, sustainable and prosper future for our nation. Copyright © 2013 Sociedade Brasileira de Quimica.
Rego R.R.,Brazilian Technological Institute of Aeronautics |
Gomes J.O.,Brazilian Technological Institute of Aeronautics |
Barros A.M.,Centro Integrado Of Manufatura E Tecnologia |
Barros A.M.,SENAI Innovation Institute for Surface Engineering
Journal of Materials Processing Technology | Year: 2013
New technologies developed for automotive engines also have highlighted the transmission torque capacity as restriction factor in the development of enhanced vehicle dynamics performance. Generally, the restriction is defined by the lifetime of the first speed gear. At the end of the gear manufacturing process, shot peening is used to induce compressive residual stresses and further increase fatigue life. This research verified the influence of introducing a bimodal media size distribution into the shot peening process. The proposal is supported by the independent effects of each media class. A higher compressive residual stress can be obtained from larger spheres. And the use of a lower diameter media class improves the surface homogeneity. The bimodal distribution was defined with a probabilistic approach over plasticity and contact stress theories. The experimental validation scope includes a topography analysis and residual stress profile measurements. The results showed mixtures combining up to an increase of 30.9% in the compressive residual stresses without jeopardising the surface quality. The collected data supported the expectation for improving the gear lifetime. It also represented the validation of a new peening process. An improvement in the product properties can be achieved in comparison to the parts produced using conventional shot peening; additionally, a lower process lead time is required in comparison to that for dual peening. © 2013 Elsevier B.V. All rights reserved.
Nascimento E.G.S.,Federal University of Espirito Santo |
Moreira D.M.,Brazilian Technological Institute of Aeronautics |
Moreira D.M.,Centro Integrado Of Manufatura E Tecnologia |
Fisch G.,Brazilian Technological Institute of Aeronautics |
Albuquerque T.T.A.,Federal University of Espirito Santo
Journal of Aerospace Technology and Management | Year: 2014
In this work we report numerical simulations of the contaminant dispersion and photochemical reactions of rocket exhaust clouds at the Centro de Lançamento de Alcântara (CLA) using the CMAQ modeling system. The simulations of carbon monoxide (CO), hydrogen chloride (HCl) and alumina (solid Al2O3) pollutants emission represent an effort in the construction of a computational tool in order to simulate normal and/or accidental events during rocket launches, making possible to predict the contaminant concentrations in accordance with emergency plans and pre and post-launchings for environmental management. The carbon monoxide and the alumina concentrations showed the formation of the ground and contrail cloud. The results also showed that hydrogen chloride concentrations would be harmful to human health, demonstrating the importance of assessing the impact of rocket launches in the environment and human health.
Moreira D.M.,Centro Integrado Of Manufatura E Tecnologia |
Albuquerque T.T.A.,Federal University of Minas Gerais
Revista Brasileira de Meteorologia | Year: 2016
An integral semi-analytical solution of the atmospheric diffusion equation considering wind speed as a function of both downwind distance from a pollution source and vertical height is presented. The model accounts for transformation and removal mechanisms via both chemical reaction and dry deposition processes. A hypothetical dispersion of contaminants emitted from an urban pollution source in the presence of mesoscale winds in an unstable atmospheric boundary layer is showed. The results demonstrate that the mesoscale winds generated by urban heat islands advect contaminants upward, which increases the intensity of air pollution in urban areas. © 2016, Sociedade Brasileira de Meteorologia. All Rights reserved.
Figueiroa C.L.S.,Centro Integrado Of Manufatura E Tecnologia
Safety, Reliability and Risk Analysis: Beyond the Horizon - Proceedings of the European Safety and Reliability Conference, ESREL 2013 | Year: 2014
The demands required by complex processes led to the development of solutions that could simultaneously treat multiple sources, processes and operations in order to enable the management of production as the conditions of the moment (production mix, machine stoppages, tight deadlines, changes priorities, ...). The segment of maintenance in most situations coexists with this context, but using as the same programming techniques for projects. The daily schedule of services in company's central workshops or in service providers puts the programmer in situations where project management techniques often fail to resolve such rules, and end up using only his experience, which is limited by human ability to manage multiple information and operations. In these situations the concepts of the Theory of Constraints and implementation of software of considering resource Finite Capacity to Advanced Scheduling fit to the situation. Besides programming, you can have more control of what happens with the equipment through monitoring using the concept of MES (Management Execution System), to take immediate action on small still or falling income. The concept also includes monitoring the condition of components in the repairs during the process by connecting to the existing inventory of spare parts. These change the paradigm of aid maintenance schedule allowing significant gains in resource productivity maintenance. This paper presents 2 cases applying the production scheduling and the concept of MES. © 2014 Taylor & Francis Group, London..