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Published By Fundacao Joaquim Nabuco

2358-3452, 0102-7352

2021 ◽  
Vol 31 (2) ◽  
pp. 61-73
Author(s):  
Gabriel Angelo Santos Mendes ◽  
Alexandre Scari

The consumption of polyethylene terephthalate (PET) has been increasing every year, as well as its recycling process as the applications of recycled PET are diversified. However, the recycling companies are not able to recycle 100% of PET because the particles with low granulometry (refuse) are not utilized because they stick to the extruder screw and are discarded. This study presents the structural dimensioning of a proposal of an equipment to sinter this refuse in some predetermined geometries, in order to achieve possible commercial applications. This structural dimensioning was done with finite element analysis open-source software Salome Meca. Some structural modifications required to achieve the design requirements are presented. Yet, the hydraulic system to operate the compression was also dimensioned.


2021 ◽  
Vol 31 (2) ◽  
pp. 1
Author(s):  
Gustavo Platt ◽  
Antônio Luís Schifino Valente

2021 ◽  
Vol 31 (2) ◽  
pp. 74-87
Author(s):  
Hiron Akira Yamada Magalhães ◽  
Talita Gama Souza ◽  
Rodrigo Felix de Araujo Cardoso ◽  
Bruno Rangel Silva ◽  
Luiz Paulo Brandão

Among several severe plastic deformation (SPD) methods, the Equal Channel Angular Pressing (ECAP) process is one of the most popular. This process's main characteristic is producing materials with ultra-fine or nanometric grains. Due to these microstructural changes, it is possible to improve mechanical properties such as strength and ductility. In this perspective, the aim of the present work was to evaluate the variations of the mechanical hardness property associated with microstructural and textural changes of pure copper as a function of its processing by SPD via ECAP. For this, the material was submitted to four passes through routes A (the sample is repetitively pressed without any rotation between each pass) and Bc (the sample is rotated in the same sense by 90° between each pass) at cold and warm temperatures. Through the obtained result, it was verified that the ambient temperature of the Bc route was the one that promoted greater homogeneity in the microstructure and weakening of the texture after the fourth pass. On the other hand, warm processing of copper by ECAP promoted a softening of the samples and a homogeneous distribution of hardness in both routes.


2021 ◽  
Vol 31 (2) ◽  
pp. 2-13
Author(s):  
José Miguel Aroztegui ◽  
Thiago José Machado

Neste artigo, vamos estudar uma forma de resolver numericamente equações diferenciais utilizando redes neurais. Basicamente, reescrevemos a equação diferencial como um problema de otimização, onde os parâmetros associados à rede neural são otimizados. A proposta deste trabalho apresentada aqui constitui uma variação da formulação introduzida por Lagaris et al. [1], diferenciando-se principalmente na forma de construção da solução aproximada. Apesar de lidarmos apenas com equações diferenciais ordinárias de primeira e segunda ordens, os resultados numéricos mostram a eficiência do método proposto. Além disso, ele possui bastante potencial, devido a quantidade de equações diferenciais e aplicações nas quais ele pode ser utilizado.


2021 ◽  
Vol 31 (2) ◽  
pp. 25-35
Author(s):  
Guilherme Balduino Lopes ◽  
Renato Ferreira Fernandes Junior.

The concept of the new industry seeks not only to improve production processes, but also to bring solutions to environmental problems, in addition to reducing resource consumption, while maintaining high yields. This constant search for process optimization has been the main agent in the development of new technologies aimed at improving the performance of industrial production lines. Thus, this article proposes to raise some important concepts of Industry 4.0, and present the development of a remote IoT-based system that, through MQTT and Modbus protocols, will be responsible for monitoring the entire electrical network of an industrial plant, sending its data to the cloud, where it can be monitored and analyzed by the industry management sector or even by an artificial intelligence system, in a simple and effective way, in real time and from anywhere, in order to assist in decision-making focused on energy efficiency.


2021 ◽  
Vol 31 (2) ◽  
pp. 36-49
Author(s):  
Lauro Miguel Lima Rocha ◽  
Marco Túlio Santana Alves

This paper deals with analyzing the structural influence of mass reliefs in spur gears. For this purpose, a system composed of pinion and a gear was designed, such that for gear several geometries were designed with different reliefs shapes and soul thicknesses. From the proposed geometries, finite element analysis (FEA) was performed, and the tooth stresses of each model were compared with the solid gear. From the results, it was observed that the tooth stresses are reduced in some cases. Besides, from the aforementioned cases, it is possible to observe that the maximum stresses may take place in its core instead of the teeth (rim area). On the other hand, based on other cases, the core thickness plays an important role as a criterion that defines the local stress.


2021 ◽  
Vol 31 (2) ◽  
pp. 14-24
Author(s):  
Naim Carvalho ◽  
Grazione De Souza Boy ◽  
Helio Pedro Amaral Souto

In this work, the numerical code DualPhysics, based on the Lagrangian particle and mesh free method Smoothed Particle Hydrodynamics, has been employed to solve the slightly compressible isothermal two-phase water-oil flow. The continuity and momentum equations are solved, and we used the modified Tait equation of state to determine the pressure. To validate the numerical code, we solved the modified Couette flow of two fluids. As a practical case, we solved the isothermal and two-dimensional two-phase water-oil flow. The mixing of the fluids occurs after passing through a 45 degree Y junction placed at the entrance of the horizontal pipeline. Results showed the potential for using the numerical code, although some modifications and alterations are still necessary to solve practical problems.


2021 ◽  
Vol 31 (2) ◽  
pp. 50-60
Author(s):  
Elisandra Freitas ◽  
George Ricardo Libardi Calixto ◽  
Juciara Alves Ferreira ◽  
Bárbara Denicol do Amaral Rodriguez ◽  
João Francisco Prolo Filho

This article investigates the numerical inversion of the Laplace Transform by the Rational-Talbot method and analyzes the influence on the variation of the free parameter N established by the technique when applied to certain functions. The set of elementary functions, for which the method is tested, has exponential and oscillatory characteristics. Based on the results obtained, it was concluded that the Rational-Talbot method is e cient for the inversion of decreasing exponential functions. At the same time, to perform the inversion process effectively for trigonometric forms, the algorithm requires a greater amount of terms in the sum. For higher values of N, the technique works well. In fact, this is observed in inverting the functions transform, that combine trigonometric and polynomial factors. The method numerical results have a good precision for the treatment of decreasing exponential functions when multiplied by trigonometric functions.


2021 ◽  
Vol 31 (1) ◽  
pp. 60-71
Author(s):  
Leonardo Acosta Martínez ◽  
Carlos Rafael García Hernández ◽  
Jesus Rosales García ◽  
Annie Ortiz Puentes

One of the challenges of future nuclear power is the development of safer and more efficient nuclear reactor designs. The AP1000 reactor based on the PWR concept of generation III + has several advantages, which can be summarized as: a modular construction, which facilitates its manufacture in series reducing the total construction time, simplification of the different systems, reduction of the initial capital investment and improvement of safety through the implementation of passive emergency systems. Being a novel design it is important to study the thermohydraulic behavior of the core applying the most modern tools. To determine the thermohydraulic behavior of a typical AP1000 fuel assembly, a computational model based on CFD was developed. A coupled neutronic-thermohydraulic calculation was performed, allowing to obtain the axial power distribution in the typical fuel assembly. The geometric model built used the certified dimensions for this type of installation that appear in the corresponding manuals. The thermohydraulic study used the CFD-based program ANSYS-CFX, considering an eighth of the fuel assembly. The neutronic calculation was performed with the program MCNPX version 2.6e. The work shows the results that illustrate the behavior of the temperature and the heat transfer in different zones of the fuel assembly. The results obtained agree with the data reported in the literature, which allowed the verification of the consistency of the developed model.


2021 ◽  
Vol 31 (1) ◽  
pp. 50-52
Author(s):  
Hermes Alves Filho ◽  
Fernando Carvalho Silva

Apresentação da Seção Especial sobre Energia Nuclear.


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