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The production of food for all the population in the world became the biggest concern. The population continues to grow and the number of farmable lands has been decreasing. To make the lands more productive, fertilizers are used on a larger scale. To guarantee the quality of the product, particle size analysis are made by mechanical sieving. With the time, the wear-out of the sieving in the fertilizer industry the results of the particle size analysis will be erroneous. So the computer vision appears as an alternative that is non-invasive and less time-consuming. In this context, this paper has the objective to develop a grain surface simulator capable of generating virtual images with overlapping grains, since there is a difficulty to obtain annotated data of images of fertilizers. In order to validate the proposed simulator using a DIP algorithm, noises are added in the virtual images to compare with the reality in the industry, to show how well the particle size analysis with computer vision were handled towards adversities. The results of the overlapping analysis show that when the virtual image has a fewer number of grains, the DIP algorithm can identify the majority of grains, consequently with less error in the particle size analysis. Different noises, at different intensities, have their effects analyzed on the algorithm. As the analyzes in this study match with the reality showing the consequences, tendencies, and errors of the overlapping of grains and noises in the images, the simulator developed here matches with reality and is extremely useful to facilitate the study of complex cases of application of visual computing and digital image processing in particle size analysis of fertilizers.

Constructal Theory has been applied to evaluate system performance in several engineering areas like solid mechanics, refrigeration, heat exchangers, etc. It states that finite flow systems performance can be optimized by minimizing the resistances. It is usually formulated by the definition of geometric constraints and an optimization method like exhaustive search or Genetic Algorithm. In present work, Constructal Theory is used in its most fundamental sense, i.e., the geometric forms should evolve (grow) from a fundamental shape, named here as Elemental Constructal (EC), instead of by the application of an optimization method to a predefined geometry. In order to test the proposed algorithm, the isotherm cavity intruded into a heat generating solid body problem is solved with proposed algorithm and solution is compared with literature solutions obtained for several pre-defined shapes (I, T, Y, X and others). If a sufficient small EC were used to define the building blocks of the cavity, thermal performance obtained with current method is comparable with performance of the best shapes found in literature. Main goal is not to find best possible geometry for the cavity, but to understand how cavity form should grow in order to reduce the temperature in solid domain. Moreover, the cavity optimization problem has only been used as an application example of a much more general methodology used to predict how shape and structure may evolve in different flow problems.

This paper develops a numerical study about the geometry of isothermal cavities in solid bodies with internal heat generation. The solid is constituted of a isotropic material, with low thermal conductivity, and adiabatic external surfaces. The cavity is used to dissipate the internally generated heat. An evolutionary algorithm is proposed, based on Constructal Theory, that builds a cavity able to maximize the heat transfer between the solid body and the ambient. Initial solid geometry (a squared fin) is divided into smaller squared elements (regions) that will be remove in order to build the cavity. First element is removed from the bottom center of the geometry and other elements are, at every step, removed so that minimize the hot spots in the solid domain. At every stage of the building process, thermal diffusion equation is numerically solved by the finite element method (FEM). The cavity construction must be flexible so that it freely progresses (evolves) in direction to the hot spots. Results show that the smaller the elements (resolution) used in the cavity construction the lower will be the maximum temperature. Besides that, present results are compare with similar works for cavities C, H, X e Y, presented in literature, showing that current methodology is very efficient in minimizing maximum solid internal temperature.

Heavy steel industries are constantly distressed with improving quality, reliability, and robustness of their product. Nevertheless, they are also concerned with reducing welding processes cost, men-power, and material waste. This leads to an interest in control techniques, automation, and robotization. Monitoring the welding process of continuously fed melting wire electrode is still an open problem, due to the instability caused by the electrical variables. We identify expressive gaps in the understanding of stability and quality of welding deposition. In this work, we introduce a low-cost system that monitors the stability of the weld bead and the transfer mode of the MIG/MAG welding process. We propose a non-intrusive solution that uses the sound signal produced by the electric arc to monitor and analyze the process in real-time. In this sense, we propose an Artificial Neural Network (ANN) based methodology to identify some types of discontinuities in the welding process. To support and foster the development of sound signal based neural network, we produce a sound signal dataset based on the experiments which recreate real situations in the welding industry. Processes with adequate conditions and welds with two types of discontinuities were executed to validate the methodology. The model performance is evaluated using both classification accuracy and confusion matrix. Results show to be possible to identify discontinuities in the welding process by looking only at the sound generated by the electric arc.

Fruit flies affect direct and indirect the fruit production, causing damage and losses in a worldwide scale. The control of fruit flies is usually done in an unregulated way, using insecticides in the form of bait-toxic, without knowledge of the infecting species. This work presents the development of an embedded system based on optoeletronic sensor to be used in an McPhail intelligent trap, sending remotely the data related to the fruit flies through a wireless protocol with low power consumption and wide range.

In the fertilizer industry, granulometric analysis is an important quality control of the product. Usually, this process is done mechanically, through sieving, which makes the process slow. As an alternative to this, a methodology based on digital image processing for fertilizer classification is proposed. This approach allows to measure feret’s diameter, area, volume and mass, important indicators to characterize fertilizers. The results obtained were validated with sieved samples and demonstrate the applicability of the method as a low cost alternative to the traditional method of granulometry of fertilizers.

The present work is guided by the Constructal theory to identify the best shapes for the cavity inserted in a cylindrical solid body with a constant heat generation rate. From the assertion that a system must evolve to persist in time, an evolution of the elemental (I-shaped) cavity to a tree-shaped cavity with two branches added to a single branch is proposed. With these modifications, two restrictions (area occupied by the trunk and area occupied by the branches of the cavity) and seven degrees of freedom are used to represent the geometry. The study focused on investigating the effect of the degrees of freedom associated with the cavity branches and the number of cavities. Results show that the optimization of each new degree reduces the maximum excess of temperature. However, the results obtained with a more complex cavity were similar to those obtained by the elemental cavity in reducing the maximum excess temperature. In practical terms, the results are similar. Despite the similarity between the present results and those achieved with a most simple shape. The increase of performance with the increase of degrees of freedom studied here indicates that for complete optimization, the performance of complex shapes can surpass that of the simplest cavity.

This work applies Constructal design to study numerically the geometry of cavities bathed by a fluid with constant heat transfer coefficient that are intruded into a cylindrical solid body. The objective is to minimize the maximum excess of temperature between the solid body and the ambient by morphing the cavity geometry. Internal heat generating is distributed uniformly into the solid body which has adiabatic conditions on the outer surfaces. The total volume and the volume of the cavities are fixed. The cavities are rectangular with variable aspect ratio. The optimized geometry and performance are reported as functions of the ratio between the volume of the cavities and the total volume, the number of cavities and the dimensionless parameter that accounts for the convective heat transfer, λ . The main results indicate that for fixed number of cavities, ϕ c , and dimensionless parameter λ , there is an optimal number of cavities, N o , that minimizes the maximum excess of temperature and this optimal number of cavities in general increases as ϕ c and λ increases.

WOS:000419407500030; International audience; The work documents the design of Earth-Air Heat Exchangers based not only on sensible heat transfer, but also on latent heat exchanges. We compare the impact of the climate of Brazil and south of France on the relevance of such systems. The duct length is determined in order to obtain maximum underground heat exchanges. A time dependent model combined to actual weather data is developed to show when an underground heat exchanger becomes a good option in a tropical climate. The three-dimensional version of the model accounts for heat transfer in the soil and for heat and moisture transfer along the underground pipe. The comparison with a 1D model allows to propose a straightforward approach to assess the cooling/heating potential of different climatic regions. (C) 2017 Elsevier Ltd. All rights reserved.

Este trabalho aplica Constructal design no estudo numérico da geometria de cavidades em contato com um fluido com coeficiente de transferência de calor constante que são inseridas em um sólido cilíndrico. Tem-se por objetivo minimizar a temperatura máxima entre o sólido e o ambiente através da variação da geometria da cavidade. A geração interna de calor é distribuída uniformemente no sólido que tem condições adiabáticas nas superfícies externas. O volume total e o volume das cavidades são fixos. As cavidades são retangulares, com razões variáveis. A geometria otimizada e desempenho são apresentados como funções da razão entre o volume das cavidades e o volume total, o número de cavidades e o parâmetro adimensional que representa a transferência de calor por convecção, λ. Os resultados principais mostram que para um número fixo de cavidades, fc e o parâmetro adimensional λ, existe um número ideal de cavidades que minimiza a temperatura máxima e este número ideal de cavidades aumenta, em geral, a medida que fc e λ aumentam.

The Simulated Annealing is a widely used metaheuristic to combinatorial and optimization problems studied since 1983, when it was first proposed. This algorithm has a particular parameter, the cooling schedule (specifically the decrease of temperature) which is still defined for each problem empirically. This study has the aim to find the best cooling schedule(s) for geometric optimization of a heat transfer problem. More specifically it is performed the geometrical evaluation of an isothermal Y-shaped cavity intruded into conducting solid wall with internal heat generation. In this research, Constructal Design is employed to determine the constraints and objectives for geometric evaluation of this problem. The cooling schedule(s) recommended here will contribute for future applications of Simulated Annealing heuristic in association with Constructal Design to seek for the optimal shapes of complex geometries in heat transfer problems, as well as, evaluate the influence of geometric parameters over thermal performance of the problem. Six different methods of decrease of temperature are evaluated in twenty samples of thirty simulations for each cooling schedule. From these simulations, it was extracted the percentage of convergence to the global optimal point. Results showed that the Fast cooling schedule led to the worst performance in the seek for the global optimal shapes, while the three hybrid cooling schedules proposed here are the most recommended to find the optimal geometrical configurations in heat transfer problems in association with Constructal Design ( BoltzExp , ConstExp1 and ConstExp2 )

This work relies on constructal design to perform the geometric optimization of the V-shaped pathways of highly conductive materials (inserts) that remove a constant heat generation rate from a body and deliver it to isothermal heat sinks. It is shown numerically that the global thermal resistance of the V-shaped pathway can be minimized by geometric optimization subject to total volume and V-shaped pathways material constraints. Constructal design and genetic algorithm (GA) optimization showed the emergence of an optimal architecture that minimizes the global thermal resistance: an optimal external shape for the assembly of pathways and optimal geometry features for the V-shaped pathway. Parametric study was performed to show the behavior of the minimized global thermal resistance as function of the volume fraction of the V-shaped pathways. First achieved results for ϕ = 0.3 indicated that when freedom is given to the geometry, the thermal performance is improved. Afterward, the employment of GA with constructal design allowed the achievement of the optimal shapes of V-shaped pathways for different volume fractions (0.2 ≤ ϕ ≤ 0.4). It was not realized the occurrence of one universal optimal shape for the several values of ϕ investigated, i.e., the optimal design was dependent on the degrees of freedom and the parameter ϕ and it is reached according to constructal principle of optimal distribution of imperfections.

In the present work constructal design is employed to optimize the geometry of a convective, Y-shaped cavity that intrudes into a solid conducting wall. The main purpose is to investigate the influence of the dimensionless heat transfer parameter a over the optimal geometries of the cavity, i.e., the ones that minimize the maximum excess of temperature (or reduce the thermal resistance of the solid domain). The search for the best geometry has been performed with the help of a genetic algorithm (GA). For square solids (H/L = 1.0) the results obtained with an exhaustive search (which is based on solution of all possible geometries) were adopted to validate the GA method, while for H/L ≠ 1.0 GA is used to find the best geometry for all degrees of freedom investigated here: H/L, t1/t0, L1/L0, and α (four times optimized). The results demonstrate that there is no universal optimal shape that minimizes the thermal field for all values of a investigated. Moreover, the temperature distribution along the solid domain becomes more homogeneous with an increase of a, until a limit where the configuration of “optimal distribution of imperfections” is achieved and the shape tends to remain fixed. Finally, it has been highlighted that the GA method proved to be very effective in the search for the best shapes with the number of required simulations much lower (8 times for the most difficult situation) than that necessary for exhaustive search.

Constructal design associated with genetic algorithm (GA) is employed to optimize the geometry of an isothermal Y-shaped cavity embedded into a solid conducting wall. The structure has four degrees of freedom (DOF). The main purpose is to minimize the maximum excess of temperature between the solid and the cavity by means of GA and exhaustive search (simulating every geometry combinations). Results showed that GA was well succeeded to find the best shapes which minimize the maximal excess of temperature with a number of simulations strongly lower than that required with exhaustive search, allowing the optimization of cavity under new constraint conditions.

This paper presents the design of a pneumatic robotic system to support the inspection of conduits according to the Electric Energy Company of the State of Rio Grande do Sul standard. Throughout the text is given an emphasis on mechanical solution developed, based on the movement of a caterpillar. Moreover, the pneumatic actuators are specified, the onboard electronics and thermal sensor used in the project. Results of the mechanical design and acquisition of images of the thermal camera are presented.

This work proposes architecture of an inspection robot's navigation system, aiming at monitoring underground energy lines. This architecture is composed of two modules: i. feature extraction from environment; ii navigation approach. The feature extraction module is based on the use of the edge detector by Canny algorithm and Hough transform for identification of lines from images of environment to monitoring. The lines identified correspond to cable conformation inside the duct. This information will serve to help the navigation system. For the implementation of the navigation system two approaches were proposed: navigation based on artificial neural network and navigation based on PID control. The navigation architecture can be used in real or simulated scenarios, and it was tested in a simulated environment.

This work proposes an architecture of an inspection robot's navigation system, aiming at monitoring of power cables in underground distribution lines. This architecture is composed of two modules: i. feature extraction from environment, ii navigation approach. The feature extraction module is based on the use of the edge detector by Canny algorithm and Hough transform for identification of lines from images of environment to monitoring. The lines identified correspond to cable conformation inside the duct. This information will serve to help the navigation system. For the implementation of the navigation system two approaches were proposed: navigation based on artificial neural network and navigation based on PID control. The navigation architecture can be used in real or simulated scenarios, and it was tested in a simulated environment.

In this paper, it is presented the development of an innovative and low-cost robotic mobile system to be employed in inspection of underground electrical distribution lines and pipes. The system is composed of a robot with different sensors (infrared, acoustic, and FEF) which permit to move inside pipes and detect overheated points, partial electrical discharges and the occurrence of cable treeing. It is showed the mechanical structure of the robot, the overall architecture of the system and preliminary results.

he problem study here is concerned with the geometrical evaluation of an isothermal Y-shaped cavity intruded into conducting solid wall with internal heat generation. The cavity acts as a sink of the heat generated into the solid. The main purpose here is to minimize the maximal excess of temperature (θmax) in the solid. Constructal Design, which is based on the objective and constraints principle, is employed to evaluate the geometries of Y-shaped cavity. Meanwhile, Simulated Annealing (SA) algorithm is employed as optimization method to seek for the best shapes. To validate the SA methodology, the results obtained with SA are compared with those achieved with Genetic Algorithm (GA) and Exaustive Search (ES) in recent studies of literature. The comparison between the optimization methods (SA, GA and ES) showed that Simulated Annealing is highly effective in the search for the optimal shapes of the studied case.