Produção Nacional
Revisado por pares
Hélio Aparecido Navarro, Luben Cabezas‐Gómez,
Due to the wide range of design possibilities, simple manufactured, low maintenance and low cost, cross-flow heat exchangers are extensively used in the petroleum, petrochemical, air conditioning, food storage, and others industries. In this paper a mathematical model for cross-flow heat exchangers with complex flow arrangements for determining epsilon -NTU relations is presented. The model is based on the tube element approach, according to which the heat exchanger outlet temperatures are obtained ...
Tópico(s): Refrigeration and Air Conditioning Technologies
2007 - Springer Science+Business Media | Brazilian Journal of Chemical Engineering
Produção Nacional
Revisado por pares
Luben Cabezas‐Gómez, Renato César da Silva, Hélio Aparecido Navarro, Fernando Eduardo Milioli,
A methodology of identification and characterization of coherent structures mostly known as clusters is applied to hydrodynamic results of numerical simulation generated for the riser of a circulating fluidized bed. The numerical simulation is performed using the MICEFLOW code, which includes the two-fluids IIT's hydrodynamic model B. The methodology for cluster characterization that is used is based in the determination of four characteristics, related to average life time, average volumetric fraction ...
Tópico(s): Mineral Processing and Grinding
2006 - Elsevier BV | Applied Mathematical Modelling
Produção Nacional
Revisado por pares
Luben Cabezas‐Gómez, Hélio Aparecido Navarro, José Maria Saíz-Jabardo,
A thorough study of the thermal performance of multipass parallel cross-flow and counter-cross-flow heat exchangers has been carried out by applying a new numerical procedure. According to this procedure, the heat exchanger is discretized into small elements following the tube-side fluid circuits. Each element is itself a one-pass mixed-unmixed cross-flow heat exchanger. Simulated results have been validated through comparisons to results from analytical solutions for one- to four-pass, parallel ...
Tópico(s): Refrigeration and Air Conditioning Technologies
2006 - ASM International | Journal of Heat Transfer
Produção Nacional
Revisado por pares
Alysson Kennerly Colaciti, Luis Miguel Valdés López, Hélio Aparecido Navarro, Luben Cabezas‐Gómez,
In the present work are presented results from numerical simulations performed with the ANSYS-CFX® code. We have studied a radial diffuser flow case, which is the main academic problem used to study the flow behavior on flat plate valves. The radial flow inside the diffuser has important behavior such as the turbulence decay downstream and recirculation regions inside the valve flow channel due to boundary layer detachment. These flow structures are present in compressor reed valve configurations, ...
Tópico(s): Wind and Air Flow Studies
2006 - Elsevier BV | Applied Mathematics and Computation
Produção Nacional
Revisado por pares
Hélio Aparecido Navarro, Luben Cabezas‐Gómez,
A new numerical methodology for thermal performance calculation in cross-flow heat exchangers is developed. Effectiveness–number of transfer units (ε–NTU) data for several standard and complex flow arrangements are obtained using this methodology. The results are validated through comparison with analytical solutions for one-pass cross-flow heat exchangers with one to four rows and with approximate series solution for an unmixed–unmixed heat exchanger, obtaining in all cases very small errors. New ...
Tópico(s): Nanofluid Flow and Heat Transfer
2005 - Elsevier BV | International Journal of Heat and Mass Transfer
Produção Nacional
Rafael Henrique Avanço, Ângelo Marcelo Tusset, José Manoel Balthazar, Airton Nabarrete, Hélio Aparecido Navarro,
This study analyzes a nonlinear system with a crank–shaft–slider mechanism linked to a pendulum. The crank is powered by a DC motor that moves horizontally the pendulum pivot. The speed of the motor is influenced by the pendulum dynamics, reason for calling the system as nonideal. In literature, the vibration of the pendulum support by a crank–shaft–slider is generally considered as harmonic what neglects the real complexity of the mechanism. It is also common, for the crank speed or the excitation ...
Tópico(s): Nonlinear Dynamics and Pattern Formation
2018 - Springer Science+Business Media | Journal of the Brazilian Society of Mechanical Sciences and Engineering
Produção Nacional
Revisado por pares
Alice Jordam Caserta, Hélio Aparecido Navarro, Luben Cabezas‐Gómez,
The soft-sphere model design of the discrete element method is based on types of dynamic systems for determining the contact forces. These forces are computed considering the solution of equation of motion for the overlap between the particles during the contact. The dynamic systems can be modeled as linear or nonlinear mass-spring-damper. In the present work we derive two new approximate relations for determining the damping coefficient and duration of contact for a specific non-linear soft-sphere ...
Tópico(s): Landslides and related hazards
2016 - Elsevier BV | Powder Technology
Produção Nacional
Revisado por pares
Hélio Aparecido Navarro, Meire Pereira de Souza Braun,
The discrete element method is a method for simulation of a particle system. For the “soft-sphere” mechanism of particle interactions, there are several models for normal contact forces, namely linear spring–dashpot, and non-linear damped Hertzian spring–dashpot, among others. The focus of this paper is to determine the normal spring stiffness coefficient of the linear model through the numerical solution for the overlap between particles in non-linear models. The linear spring stiffness is determined ...
Tópico(s): Soil Mechanics and Vehicle Dynamics
2013 - Elsevier BV | Powder Technology
Produção Nacional
Revisado por pares
Luben Cabezas‐Gómez, Hélio Aparecido Navarro, José Maria Saíz-Jabardo, Sérgio de Morais Hanriot, Cristiana Maia,
The present paper presents a theoretical analysis of a cross flow heat exchanger with a new flow arrangement comprehending several tube rows. The thermal performance of the proposed flow arrangement is compared with the thermal performance of a typical counter cross flow arrangement that is used in chemical, refrigeration, automotive and air conditioning industries. The thermal performance comparison has been performed in terms of the following parameters: heat exchanger effectiveness and efficiency, ...
Tópico(s): Heat Transfer Mechanisms
2012 - Elsevier BV | International Journal of Thermal Sciences
Produção Nacional
Revisado por pares
Meire Pereira de Souza Braun, Andreza Tangerino Mineto, Hélio Aparecido Navarro, Luben Cabezas‐Gómez, Renato César da Silva,
The numerical diffusion effects appear due to the discretization process of the convective terms of the transport equations. This phenomenon takes place also in the numerical simulation of gas–solid two-phase flows in bubbling fluidized beds (BFB). In the present work a comparative analysis of the numerical results obtained using two interpolation schemes for convective terms, namely FOUP (First Order UPwind) and a high order scheme (Superbee) is presented. The equations are derived by considering ...
Tópico(s): Particle Dynamics in Fluid Flows
2010 - Pergamon Press | Mathematical and Computer Modelling
Produção Nacional
Revisado por pares
Luben Cabezas‐Gómez, Hélio Aparecido Navarro, Sergio Godoy, Antonio Campo, José Maria Saíz-Jabardo,
The objective of the present paper is to thermally characterize a cross-flow heat exchanger featuring a new cross-flow arrangement, which may find application in contemporary refrigeration and automobile industries. The new flow arrangement is peculiar in the sense that it possesses two fluid circuits extending in the form of two tube rows, each with two tube lines. To assess the heat exchanger performance, it is compared against that for the standard two-pass counter-cross-flow arrangement. The ...
Tópico(s): Heat Transfer and Boiling Studies
2009 - Elsevier BV | International Journal of Thermal Sciences
Produção Nacional
Revisado por pares
Marilda Carlos Vidotto, Helio R. Navarro, Luis Carlos Jabur Gaziri,
Fifty strains of Escherichia coli isolated from coliseptcemic chickens in Londrina, Brazil, were examined for presence of gene sequences for pil and pap, hemagglutination, and adherence to chicken tracheal cells. Forty-one strains were pil+ and 22 of these showed mannose sensitive (MS) hemagglutination (MSHA) of guinea-pig erythrocytes, indicating that they possessed only type 1 pili. Seven strains were pap+ and 6 of these caused mannose resistant (MR) hemagglutination (MRHA) of human erythrocytes. ...
Tópico(s): Bacteriophages and microbial interactions
1997 - Elsevier BV | Veterinary Microbiology
Produção Nacional
Gherhardt Ribatski, Luben Cabezas‐Gómez, Hélio Aparecido Navarro, José Maria Saíz-Jabardo,
In this paper, the importance of the development of new high power density thermal management systems for electronic devices is assessed. It is described the new heat sink technologies under development to be used in the cooling of microprocessors. The main difficulties to be overcome before the spreading of one specific heat sink configuration are identified. At the end, it is concluded that a heat sink based on flow boiling in micro-scale channels is the most promising approach.
Tópico(s): Refrigeration and Air Conditioning Technologies
2007 - UNIVERSIDADE FEDERAL DO PARANÁ | Revista de Engenharia Térmica
Peter B. Winter, Renée M. Brielmann, Nicholas P. Timkovich, Helio T. Navarro, Andreia Teixeira‐Castro, Richard I. Morimoto, Luı́s A. Nunes Amaral,
Abstract The study of C. elegans has led to ground-breaking discoveries in gene-function, neuronal circuits, and physiological responses. Subtle behavioral phenotypes, however, are often difficult to measure reproducibly. We have developed an experimental and computational infrastructure to simultaneously record and analyze the physical characteristics, movement, and social behaviors of dozens of interacting free-moving nematodes. Our algorithm implements a directed acyclic network that reconstructs ...
Tópico(s): Circadian rhythm and melatonin
2016 - Nature Portfolio | Scientific Reports
Produção Nacional
Revisado por pares
Rafael Henrique Avanço, Hélio Aparecido Navarro, Reyolando Manoel Lopes Rebello da Fonseca Brasil, José Manoel Balthazar, Átila Madureira Bueno, Ângelo Marcelo Tusset,
The nonlinear dynamics behavior analyzed, in this paper, consists in a pendulum vertically excited on the support by a crank-shaft-slider mechanism. The novelty is the obtainment and analysis of a mathematical model for the pendulum dynamics, under an excitation of a crank-slider, which is based on an extension of the mathematical model of the classical parametric pendulums. Through the modeling, it was verified that the nonlinear dynamics of the pendulum, excited by the crank-shaft-slider mechanism ...
Tópico(s): Quantum chaos and dynamical systems
2015 - Springer Science+Business Media | Meccanica
Produção Nacional
Luben Cabezas‐Gómez, Hélio Aparecido Navarro, José Maria Saíz-Jabardo,
This monograph introduces a numerical computational methodology for thermal performance modeling of cross-flow heat exchangers, with applications in chemical, refrigeration and automobile industries.
Tópico(s): Heat Transfer and Optimization
2014 - Springer Nature | SpringerBriefs in applied sciences and technology
Produção Nacional
Revisado por pares
Luben Cabezas‐Gómez, José Maria Saíz-Jabardo, Hélio Aparecido Navarro, Paulo Eduardo Lopes Barbieri,
This study provides new effectiveness data and closed form relations for some recently proposed cross-flow heat exchanger flow arrangements of industrial and research interest. The study also covers the so called Z-shape flow arrangement of widespread use in the refrigeration and automobile industries. The closed form relations as well as the effectiveness data are presented in the standard effectiveness – number of transfer units (ɛ-NTU) format. Slight deviations have been observed of the arithmetic ...
Tópico(s): Refrigeration and Air Conditioning Technologies
2013 - Elsevier BV | International Journal of Heat and Mass Transfer
Produção Nacional
Revisado por pares
Rafael Henrique Avanço, Ângelo Marcelo Tusset, Marcelo Suetake, Hélio Aparecido Navarro, José Manoel Balthazar, Airton Nabarrete,
In this paper a mathematical model was found, and numerical results obtained for the pendulum behavior when coupled to a DC generator. A simple pendulum is vertically excited on its support and consequently exhibiting oscillations and rotations. The motion of the pendulum spins the axis of a DC generator and inducing a current. The dynamic model involving the generator and the pendulum dynamics is developed and analyzed in this article. Bifurcation diagrams demonstrate doubling-period and saddle- ...
Tópico(s): Wave and Wind Energy Systems
2019 - Brazilian Society of Mechanical Sciences and Engineering | Latin American Journal of Solids and Structures
Produção Nacional
Hélio Aparecido Navarro, Luben Cabezas‐Gómez, João R. Bastos Zoghbi Filho, Gherhardt Ribatski, José Maria Saíz-Jabardo,
A simulation program based on a control volume analysis has been used in the evaluation of the (ε, NTU) relationship for coils of complex geometry and flow arrangement. The simulation program has been evaluated through simple geometry and flow arrangement coils. The program results compare very well with correlations for simple cross flow coils, and a number of rows up to four. It has also been determined that closed form correlations developed for coils of an infinite number of tube rows are inadequate ...
Tópico(s): Refrigeration and Air Conditioning Technologies
2010 - Springer Science+Business Media | Journal of the Brazilian Society of Mechanical Sciences and Engineering
Produção Nacional
Revisado por pares
Hélio Aparecido Navarro, Luben Cabezas‐Gómez, Renato César da Silva, Arlindo Neto Montagnoli,
Tópico(s): Computational Fluid Dynamics and Aerodynamics
2006 - Elsevier BV | Applied Mathematics and Computation
Produção Nacional
Revisado por pares
Hélio Aparecido Navarro, L. Cvetićanin,
Tópico(s): Bladed Disk Vibration Dynamics
2016 - Elsevier BV | Applied Mathematics and Computation
Produção Nacional
Revisado por pares
Camila Machado de Souza, Maria Ângela Tardelli, Hélio Tedesco‐Silva, Natalia Navarro García, M. Parreño Caparrós, José Antonio Álvarez Gómez, Itamar Souza de Oliveira-Júnior,
Renal failure affects the pharmacology of nondepolarizing neuromuscular blockers making recovery of neuromuscular function unpredictable. Sugammadex antagonises rocuronium-induced neuromuscular blockade by encapsulating rocuronium, creating a stable complex molecule that is mainly excreted by the kidneys. Previous studies suggest that sugammadex is effective in reversing moderate neuromuscular block in the presence of renal failure, but no data are available regarding reversal of profound neuromuscular ...
Tópico(s): Nausea and vomiting management
2015 - Lippincott Williams & Wilkins | European Journal of Anaesthesiology
Produção Nacional
Revisado por pares
Ester Pires de Almeida, Igor Pinheiro de Brito, H. C. Ferreira, Hélio de Lucena Lira, Lisiane Navarro de Lima Santana, Gelmires de Araújo Neves,
The purpose of this study was to obtain cordierite from compositions containing kaolin waste (with different particle-size distributions), talc and magnesium oxide, for use in the production of refractory and insulating materials. The samples were characterized by means of the following techniques: chemical analysis by X-ray fluorescence, X-ray diffraction, particle size analysis and thermogravimetric and differential thermal analysis. The microstructure of the samples was analyzed using scanning ...
Tópico(s): Advanced ceramic materials synthesis
2017 - Elsevier BV | Ceramics International
Produção Nacional
Revisado por pares
Valmir José da Silva, Michelle Félix de Andrade, Wherllyson Patrício Gonçalves, Romualdo Rodrigues Menezes, Gelmires de Araújo Neves, Hélio de Lucena Lira, Lisiane Navarro de Lima Santana,
In the production of alumina by the Bayer process, the calcination step generates a waste containing ~90% aluminum oxide (Al2O3). Due to the high content of this oxide, this waste can be used as a source of alumina in porcelain formulations, especially those used in the synthesis of mullite. The purpose of this study was to produce porous mullite blocks using compositions containing kaolin and alumina waste. The compositions were formulated based on a mullite stoichiometry of 3:2. Heat treatments ...
Tópico(s): Advanced ceramic materials synthesis
2016 - Elsevier BV | Ceramics International
Produção Nacional
Revisado por pares
Wherllyson Patrício Gonçalves, Valmir J. Silva, Romualdo Rodrigues Menezes, Gelmires de Araújo Neves, Hélio de Lucena Lira, Lisiane Navarro de Lima Santana,
Tópico(s): Concrete and Cement Materials Research
2016 - Elsevier BV | Applied Clay Science
Produção Nacional
Revisado por pares
Andreza Tangerino Mineto, Meire Pereira de Souza Braun, Hélio Aparecido Navarro, Luben Cabezas‐Gómez,
Abstract This article describes a mathematical model and numerical simulation of gas-solid flow in a bubbling fluidized bed (BFB), where the the two-fluid Eulerian-Eulerian model was used and the solid phase stress tensor was modeled considering both the friction between particles and the kinetic theory of granular flows. The code MFIX (Multiphase Flow with Interphase eXchanges) developed by NETL (National Energy Technology Laboratory, U. S. Department of Energy) was used for numerical simulations, ...
Tópico(s): Particle Dynamics in Fluid Flows
2014 - Taylor & Francis | Chemical Engineering Communications
Produção Nacional
Kátia Denise Saraiva Bresciani, Alvimar José da Costa, Italmar Teodorico Navarro, Gilson Hélio Toniollo, Cláudio Alessandro Massamitsu Sakamoto, Tiago Pereira Arantes, Solange María Gennari,
Inquiries about toxoplasmosis are essential because its zoonotic potential and pathogenicity in pets and production animals. The dog can be involved in the mechanical transmission of the infection by Toxoplasma gondii and in spite of not being the definitive host, it has an epidemiological role in this disease. The high rate of dogs naturally infected by T. gondii and the great possibility of adquiring this protozoan, justify the importance of attempting against for the occurrence of this illness. ...
Tópico(s): Herpesvirus Infections and Treatments
2008 - UNIVERSIDADE ESTADUAL DE LONDRINA | Semina Ciências Agrárias
Produção Nacional
Revisado por pares
Valmir José da Silva, Salvador K. A. Taveira, Karina Ribeiro Silva, Gelmires de Araújo Neves, Hélio de Lucena Lira, Lisiane Navarro de Lima Santana,
Refractory ceramics were produced from clays and alumina waste. Specimens were shaped by uniaxial pressing, subjected to thermal analysis by dilatometry and heat-treated in a conventional furnace at 1300 and 1400ºC, applying a heating rate of 5ºC/min and a dwell time of 2 and 3 hours at the maximum temperature. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and physicomechanical properties. The dilatometric analysis before heat treatment indicated that ...
Tópico(s): Advanced ceramic materials synthesis
2021 - Associação Brasileira de Metalurgia e Materiais (ABM); Associação Brasileira de Cerâmica (ABC); Associação Brasileira de Polímer | Materials Research
Produção Nacional
Revisado por pares
Maria Isabel Brasileiro, D.H.S. Oliveira, Hélio de Lucena Lira, Lisiane Navarro de Lima Santana, Gelmires de Araújo Neves, A.P. Novaes, J.Marcos Sasak,
In the process of kaolin improvement to types of residue are generated and dispose in the environment. The first residue, about 70%wt, generated from the washing of the kaolin and the second generated residue from the improvement in sieve 200 mesh (0.074mm), of the remaining of the washed kaolin 30%. These residues can present excellent qualities to be used as raw materials rich in kaolinite. Kaolinite when is submitted to heat give two stable phases: mullite and crystobalite. The properties of mullite, ...
Tópico(s): Concrete and Cement Materials Research
2006 - Trans Tech Publications | Materials science forum
Produção Nacional
Revisado por pares
Valmir José da Silva, Ester Pires de Almeida, Wherllyson Patrício Gonçalves, Raphael Borges da Nóbrega, Gelmires de Araújo Neves, Hélio de Lucena Lira, Romualdo Rodrigues Menezes, Lisiane Navarro de Lima Santana,
Tópico(s): Ferroelectric and Piezoelectric Materials
2018 - Elsevier BV | Ceramics International