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Numerical Analysis of Phase Change Material Parameters on the Behavior of a Ground-Air Heat Exchanger

Defect and Diffusion Forum 2024年 436卷 103-115页

作者： Vivas, Giovanni Antonio Vielma Rodrigues, Michel Kepes Rocha, Luiz Alberto Oliveira Dos Santos, Elizaldo Domingues Brum, Ruth da Silva Isoldi, Liércio André Graduate Program in Computational Modeling Federal University of Rio Grande RS Rio Grande Brazil Graduate Program in Mathematical Modeling Federal University of Pelotas RS Pelotas Brazil

The ground-air heat exchanger (GAHE) represents an eco-friendly solution for improving temperature conditions and, consequently, lowering the power demand in facilities. The aim of this research is to numerically analyze how the length and position of the phase change material (PCM) affect the behavior of the GAHE. To achieve this, a 3D computational simulation of the PCM integrated with the GAHE was employed, utilizing the equivalent heat capacity approach and tailored to the climate and ground properties of southern Brazil. This GAHE-PCM numerical model was created employing the finite volume method through the ANSYS Fluent program. From the obtained results, it was found that for a PCM length of 20.61 m, the incorporation of this material placed from the duct inlet offered an improvement of 13.37% in the average heating energy performance indicator (EPI) in the month of May, in contrast to the EPI value of 18.04% achieved when the PCM was added from the duct outlet. © 2024 Trans Tech Publications Ltd, All Rights Reserved.

关键词： Ducts

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computational modeling of an Earth-Air Heat Exchanger Integrated with Phase Change Materials: A Case Study Performed for the Viamão City, Rio Grande do Sul State, Brazil

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Defect and Diffusion Forum 2023年 427卷 85-94页

作者： Vielma Vivas, Giovanni Antonio Rodrigues, Michel Kepes Alberto, Luiz Rocha, Oliveira Dos Santos, Elizaldo Domingues Silva Brum, Ruth da Isoldi, Liércio André Graduate Program in Computational Modeling Federal University of Rio Grande RS Rio Grande Brazil Graduate Program in Mathematical Modeling Federal University of Pelotas RS Pelotas Brazil

The earth-air heat exchanger (EAHE) is a sustainable option that allows the electrical energy consumption reduction in buildings. The objective of this study is to evaluate the influence of the incorporation of the thermal energy storage principle based on phase change materials (PCM) into the EAHE on its thermal potential. For this, a three-dimensional numerical model of the PCM coupled to the EAHE (EAHE-PCM) was developed based on the effective heat capacity method and adapted to the climatic conditions and soil characteristics of the Viamão city, Rio Grande do Sul State, Brazil. It was found that for a duct diameter and length of 0.11 m and 25.77 m, the incorporation of PCM to EAHE improved by 8.90% and 3.97% in the average annual thermal potential of heating and cooling, respectively. In addition, the average monthly thermal potential increased 19.70% (heating) and 8.48% (cooling), for the months of May and December, respectively, when the PCM was integrated into the system. © 2023 Trans Tech Publications Ltd, Switzerland.

关键词： Phase change materials

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Numerical Simulation of Vertical Helical Earth-Air Heat Exchangers: Multiobjective Performance Assessment

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Defect and Diffusion Forum 2024年 435卷 77-89页

作者： Razera, Andre Luis Vaz, Igor Silva Kepes Rodrigues, Michel Domingues Dos Santos, Elizaldo Oliveira Rocha, Luiz Alberto Isoldi, Liércio Andre School of Engineering Universidade Federal do Rio Grande Rio Grande RS Brazil Graduate Program in Computational Modeling Universidade Federal do Rio Grande Rio Grande RS Brazil

In the present study, a numerical evaluation of the thermal behavior of Vertical Helical Earth-Air Heat Exchangers (EAHE-VH) installations was conducted under representative climate and soil conditions of the city of Rio Grande, in southern Brazil. The Rectilinear Horizontal Earth-Air Heat Exchanger (EAHE-HR), traditionally employed, was used as a reference. The evaluated geometric variable was the pitch between the helicoids (Ph), and the performance was quantified bythe thermal potential of the system, allowing for quantitative comparisons between the different EAHEs through statistical indicators. Comparisons were also made with the Vertical Earth-Air Heat Exchanger with 3 U-shaped ducts (EAHE-V3U). As a result, the option of EAHE-VH with a pitch of 100 mm achieved superior performance of up to 20% compared to the other helical geometries studied. Additionally, it reached the result closest to the EAHE-HR considered as a reference. When compared to the EAHE-V3U, it showed lower results related to the annual thermal potential. However, it stood out for the need for a smaller volume of soil for its installation, with a reduction of 51.5% compared to the EAHE-V3U and 79.1% compared to the EAHE-HR. The multi objective analysis showed the ability of the EAHE-VH to simultaneously meet the objectives related to thermal potential and required volume for installation, making it the most viable option among the evaluated EAHE construction models when both purposes are equally important. © 2024 Trans Tech Publications Ltd, All Rights Reserved.

关键词： Air preheaters

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Applying computational Intelligence to Improve Judiciary Efficiency 5

Applying Computational Intelligence to Improve Judiciary Eff...

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5th International Conference on Transdisciplinary AI, TransAI 2023

作者： Ferrari Faccioni, Marcelo Augusto Da Silva Lisboa, Marcelo Rocha, Marcelo Lisboa Prata, David Nadler Barbosa, Gentil Veloso 1st Special Court of the District of Palmas Court of Justice of Tocantins TO Palmas Brazil Information Technology Department Secretary of Administration of Tocantins TO Palmas Brazil Federal University of Tocantins Postgraduate Program in Computational Systems Modeling TO Palmas Brazil Federal University of Tocantins Program in Computational Systems Modeling TO Palmas Brazil

ISBN: (纸本)9798350358018

The present work aims to demonstrate that the use of computational intelligence in judicial provision can bring speed and legal certainty to judicial decisions. The possibility of using a technological tool based on processing in natural language and textual classification will be created and then evaluated for the simultaneous application of judicial precedents. With this, it will be sought to prove that the judicial decision can be rendered more quickly. Through the use of computational intelligence, we carried out the reading of the initial petition of processes distributed with the Special Courts of the District of Palmas-Toin Brazil in the years 2019 to 2022, focusing in the binding precedents edited by the STF and ST J. We seek the possible incidence and application of the binding precedent in the specific case and thus demonstrate that the judge could know, right after the filing of the action, that the object of the inaugural claim already had a manifestation of the STF or STJ and therefore it would be up to the judgment of injunction, and thus prove the possibility of obtaining speed and legal certainty in the jurisdictional provision with the combined use of technology with binding precedents. © 2023 IEEE.

关键词： Artificial intelligence

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A mathematical model of the innate immunological response to Brucella infection

A mathematical model of the innate immunological response to...

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2024 IEEE International Conference on Bioinformatics and Biomedicine, BIBM 2024

作者： De Oliveira, João Víctor Costa Borges, Carlos Cristiano Hasenclever De Almeida, Leonardo Augusto Lobosco, Marcelo Federal University of Juiz de Fora Graduate Program on Computational Modeling Juiz de Fora Brazil Federal University of Alfenas Laboratory of Molecular Biology of Microorganisms Alfenas Brazil

ISBN: (纸本)9798350386226

Brucellosis is a highly contagious zoonotic disease caused by bacteria from the genus Brucella. It affects various animal species, with significant economic consequences for live-stock producers. The disease causes reproductive losses, such as abortions and reduced fertility, leading to decreased live-stock production. Additionally, infected animals may experience reduced milk production and weight gain, further impacting the economic viability of livestock operations. Furthermore, the potential for zoonotic transmission to humans poses risks to public health. In this study, we propose a new mathematical model that describes the innate immune response to brucellosis, focusing on the interactions between antigens and the innate immune system. The model is formulated as a system of five partial differential equations that represent healthy tissue, bacteria, cytokines, resting and mature antigen-presenting cells, and is solved using the finite difference method. To validate our model, we compare the initial numerical results with experimental data from the literature, achieving an absolute error of 0.0017. © 2024 IEEE.

关键词： Finite difference method

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Replacing the FitzHugh-Nagumo Electrophysiology Model by Physics-Informed Neural Networks 23rd

Replacing the FitzHugh-Nagumo Electrophysiology Model by P...

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23rd International Conference on computational Science, ICCS 2023

作者： Werneck, Yan Barbosa dos Santos, Rodrigo Weber Rocha, Bernardo Martins Oliveira, Rafael Sachetto Graduate Program in Computational Modeling Federal University of Juiz de Fora Juiz de Fora Brazil Graduate Program in Computer Science Federal University of São Jõao del Rei São Jão del Rei Brazil

ISBN: (纸本)9783031360206

This paper presents a novel approach to replace the FitzHugh-Nagumo (FHN) model with physics-informed neural networks (PINNs). The FHN model, a system of two ordinary differential equations, is widely used in electrophysiology and neurophysiology to simulate cell action potentials. However, in tasks such as whole-organ electrophysiology modeling and drug testing, the numerical solution of millions of cell models is computationally expensive. To address this, we propose using PINNs to accurately approximate the two variables of the FHN model at any time instant, any initial condition, and a wide range of parameters. In particular, this eliminates the need for causality after training. We employed time window marching and increased point cloud density on transition regions to improve the training of the neural network due to nonlinearity, sharp transitions, unstable equilibrium, and bifurcations of parameters. The PINNs were generated using NVIDIA’s Modulus framework, allowing efficient deployment on modern GPUs. Our results show that the generated PINNs could reproduce FHN solutions with average numerical errors below 0.5%, making them a promising lightweight computational model for electrophysiology and neurophysiology research. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Electrophysiology

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Four-phase Buck Converter Design and Thermal modeling Using FEA Simulation 14

Four-phase Buck Converter Design and Thermal Modeling Using ...

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14th Seminar on Power Electronics and Control, SEPOC 2022

作者： Eckhardt, Gustavo Lenz, Joao Manoel An Electrical Engineering Undergrad with A Scientific Initiation Scholarship at Unijuí Brazil Unijúi Brazil Mathematical and Computational Modeling Graduate Program Unijúi Brazil Brazil

ISBN: (数字)9781665470896

ISBN: (纸本)9781665470896

Equipment with high efficiency, high power density, reduced size and low cost are in demand in the automotive industry. This work presents a method to design and model a high power-density four-phase DC-DC Buck converter for an automotive application and using the components operating temperature as a design criteria. A parameter sweep is done to select the operating point of the DC-DC converter combined with an iterative method to select part numbers, where preference is given to components that are AEC-Qxxx qualified. The converter is modeled and power losses are computed in SPICE considering the parasitic elements present in the PCB and the dynamic characteristics and non-idealities of the electronic components;thermal modeling is performed using Ansys Icepak. The results indicate that the design meets all electrical and thermal requirements for an automotive application. An efficiency of 95.97% is obtained in a four-phase DC-DC Buck converter that supplies a total of 800 W to 4 loads, in a space of 43.77 cm3, that is, an estimated power density of 18.28 W/cm3. © 2022 IEEE.

关键词： Buck converter

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Semi-analytical finite element method applied for characterizing micropolar fibrous composites

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Applied Mathematics and Mechanics(English Edition) 2024年第12期45卷 2147-2164页

作者： J.A.OTERO Y.ESPINOSA-ALMEYDA R.RODRIGUEZ-RAMOS J.MERODIO School of Engineering and Sciences Monterrey Institute of TechnologyEstado de Mexico 52926Mexico Institute of Engineering and Technology Autonomous University of Ciudad JuarezCiudad JuarezChihuahua 32310Mexico Postgraduate Program in Computational Modeling in Science and Technology Federal Fluminense UniversityRıo de Janeiro 27255-125Brazil Faculty of Mathematics and Computer Science University of HavanaLa Habana 10400Cuba Department of Mathematics Applied to ICT School of Informatics Systems EngineeringTechnical University of MadridMadrid 28031Spain

A semi-analytical finite element method(SAFEM),based on the two-scale asymptotic homogenization method(AHM)and the finite element method(FEM),is implemented to obtain the effective properties of two-phase fiber-reinforced composites(FRCs).The fibers are periodically distributed and unidirectionally aligned in a homogeneous *** framework addresses the static linear elastic micropolar problem through partial differential equations,subject to boundary conditions and perfect interface contact *** mathematical formulation of the local problems and the effective coefficients are presented by the *** local problems obtained from the AHM are solved by the FEM,which is denoted as the *** numerical results are provided,and the accuracy of the solutions is analyzed,indicating that the formulas and results obtained with the SAFEM may serve as the reference points for validating the outcomes of experimental and numerical computations.

关键词： semi-analytical approach fiber-reinforced composite(FRC) effective property finite element method(FEM) asymptotic homogenization method(AHM) micropolar elasticity

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School dropout in the Federal Network Education of Brazil: is it an inherent individual attribute or it lies on setting conditions? 25

School dropout in the Federal Network Education of Brazil: i...

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25th International Symposium on Computers in Education, SIIE 2023

作者： Dias, Jabson Cavalcante Da Silva, Tadeu Lucena Juliatto, Marco Antonio Da Paixao, Adriano Nascimento Prata, David Nadler Federal University of Tocantins TO Palmas77001-090 Brazil Federal University of Paraíba Statistic Department Paraíba PB Brazil Federal University of Tocantins Institute of Regional Development Graduate Program of Computational Modeling TO Palmas77001-090 Brazil

ISBN: (纸本)9798350329315

Studies shown that school dropout among young people in Brazil corresponds to 3% of the annual GDP and is equivalent to all state and municipal spending on basic education per year. The expectation is that, each year, the country has approximately 575,000 young people without basic education due to school dropout. Many aspects can lead to greater or lesser school dropouts. An important issue that can help to understand this school phenomenon is to disentangle which attributes are inherent to the individual and which are attributed to the setting, so that public policies could be developed in favor of reducing schools' dropouts. In this work, logistic regression methods were applied to the 2019 Nilo Peçanha Platform databases (approximately 250 thousand records). Results shown that demographic, geographic, economic, and school setting variables can be measured to understand their impacts in projecting schools' dropouts, enabling the elaboration and carrying out of preventive and corrective actions in schools. © 2023 IEEE.

关键词： Logistic regression

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Early surveillance of rice bakanae disease using deep learning and hyperspectral imaging

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aBIOTECH 2024年第3期5卷 281-297页

作者： Sishi Chen Xuqi Lu Hongda Fang Anand Babu Perumal Ruyue Li Lei Feng Mengcen Wang Yufei Liu College of Biosystems Engineering and Food Science Zhejiang UniversityHangzhou 310058China State Key Laboratory of Rice Biology and Breeding Zhejiang UniversityHangzhou 310058China Computational Modeling and Nanoscale Processing Unit National Institute of Food TechnologyEntrepreneurship and Management-ThanjavurMinistry of Food Processing IndustriesThanjavur 613005India College of Environmental and Resource Sciences Zhejiang UniversityHangzhou 310058China Global Education Program for AgriScience Frontiers Graduate School of AgricultureHokkaido UniversitySapporo 060-8589Japan

Bakanae disease,caused by Fusarium fujikuroi,poses a significant threat to rice production and has been observed in most rice-growing *** disease symptoms caused by different pathogens may vary,including elongated and weak stems,slender and yellow leaves,and dwarfism,as *** disease is likely to cause necrosis of diseased seedlings,and it may cause a large area of infection in the field through the transmission of ***,early disease surveillance plays a crucial role in securing rice *** monitoring methods are both time-consuming and labor-intensive and cannot be broadly *** this study,a combination of hyperspectral imaging technology and deep learning algorithms were used to achieve in situ detection of rice seedlings infected with bakanae *** data were obtained on the 9th,15th,and 21st day after rice infection to explore the physiological and biochemical performance,which helps to deepen the research on the disease *** data were obtained over these same periods of infection,and a deep learning model,named Rice Bakanae Disease-Visual Geometry Group(RBD-VGG),was established by leveraging hyperspectral imaging technology and deep learning *** on this model,an average accuracy of 92.2%was achieved on the 21st day of *** also achieved an accuracy of 79.4%as early as the 9th *** characteristic wavelengths were extracted to increase the feasibility of using portable spectral equipment for field ***,the model offers an efficient and non-destructive surveillance methodology for monitoring bakanae disease,thereby providing an efficient avenue for disease prevention and control.

关键词： Bakanae disease Hyperspectral imaging Deep learning Early surveillance Disease monitoring

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