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SSRN 2023年

作者： da Conceição, Marceli do Nascimento da Fonseca, Henrique Massard da Conceição Ribeiro, Roberto Carlos da Silva Moreira Thiré, Rossana Mara Program of Metallurgical and Materials Engineering-PEMM COPPE Universidade Federal do Rio de Janeiro – UFRJ Rio de Janeiro21941-598 Brazil Centre for Mineral Technology - CETEM Brazil Mechanical Engineering Department Universidade Federal Fluminense -UFF Brazil

The Material Extrusion (ME) is the most used technique in the Additive Manufacturing (AM) process. The understanding of the behavior of heat losses in situ is crucial to enhance the mechanical properties of the parts being manufactured. Polymer cooling analysis is one of the main pillars for obtaining superior properties in traditional polymer processing. For such analysis, infrared thermographic cameras can be used as a tool for the non-contact temperature measurement. The numerous variables in the construction of the piece offer potential for such investigation. This study may lead not only to the enhancement of the part manufactured, but also to improvements on the 3D printer itself. In addition, the polymer matrix and the manufacturing software can also be optimized. The main objective of this work is to determine the cooling profile of parts printed with Poly(lactic acid)(PLA) filament using an infrared camera for the temperature measurements in real time, which were processed with Matlab® as a function of time and of the part length. Different cooling profiles were observed along the deposited layer, mainly when comparing the edges of the same layer. A difference of up to 30 °C was observed between these edges and non-uniform heat losses profiles were also observed at the beginning, middle and end of the part manufacturing. Several strategies are proposed to enhance the heat losses distribution during the cooling process. © 2023, The Authors. All rights reserved.

关键词： Lactic acid

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Property-Based Transparency: a New Utility definition*

Property-Based Transparency: a New Utility Definition*

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IEEE International Conference on Automation Science and engineering (CASE)

作者： Patrícia C. Mayer Felipe G. Cabral Públio M. M. Lima Marcos V. Moreira Audine Subias Yannick Pencolé Department of Automation and Systems Federal University of Santa Catarina Florianópolis SC Brazil COPPE - Electrical Engineering Program Universidade Federal do Rio de Janeiro Cidade Universitária Rio de Janeiro RJ Brazil LAAS-CNRS INSA University of Toulouse France LAAS-CNRS CNRS University of Toulouse France

ISBN: (数字)9798350358513

ISBN: (纸本)9798350358520

Cyber-physical systems (CPSs) are composed of computational and physical components that interact to achieve a desired behavior for a given system. These systems are widely used in industrial applications and have guaranteed a solid improvement in productivity. However, their high connectivity also makes them more vulnerable to cyber-attacks, and thus, strategies to increase and/or guarantee the privacy of classified information are mandatory. On the other hand, the availability of system information, known as utility, to trustworthy agents is fundamental to operating large-scale CPSs efficiently, which establishes a trade-off between the privacy of information against malicious agents and the utility of data to legitimate receivers. In this paper, we explore the utility problem for CPSs abstracted as Discrete-Event systems (deSs), where the intended receiver must know useful information about the system to achieve a desired goal. In this context, we consider that this information is the ability to be sure when a given property of interest is satisfied before the system evolves to a state where this property is no longer valid. To this end, we propose a new utility notion called Property-Based Transparency (PT), and a method for verifying whether a system is transparent with respect to the desired property. In addition, we discuss PT’s applicability in two domains and present how it relates to the notion of current-state opacity and fault diagnosis of deS.

关键词： Fault diagnosis Productivity Privacy Data privacy Computer aided software engineering Receivers Cyber-physical systems Solids Discrete-event systems Cyberattack

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On nonrepetitive colorings of paths and cycles

arXiv

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arXiv 2023年

作者： Botler, Fábio Lomenha, Wanderson de Souza, João Pedro Program System Engineering and Computer Science COPPE Brazil Universidade Federal do Rio de Janeiro Brazil Colégio Pedro II Brazil

We say that a sequence a1 · · · a2t of integers is repetitive if ai = ai+t for every i ∈ {1, ..., t}. A walk in a graph G is a sequence v1 · · · vr of vertices of G in which vivi+1 ∈ E(...

We say that a sequence a1 · · · a2t of integers is repetitive if ai = ai+t for every i ∈ {1, ..., t}. A walk in a graph G is a sequence v1 · · · vr of vertices of G in which vivi+1 ∈ E(G) for every i ∈ {1, ..., r − 1}. Given a k-coloring c: V (G) → {1, ..., k} of V (G), we say that c is walk-nonrepetitive (resp. stroll-nonrepetitive) if for every t ∈ N and every walk v1 · · · v2t the sequence c(v1) · · · c(v2t) is not repetitive unless vi = vi+t for every i ∈ {1, ..., t} (resp. unless vi = vi+t for some i ∈ {1, ..., t}). The walk (resp. stroll) chromatic number σ(G) (resp. ρ(G)) of G is the minimum k for which G has a walk-nonrepetitive (resp. stroll-nonrepetitive) k-coloring. Let Cn and Pn denote, respectively, the cycle and the path with n vertices. In this paper we present three results that answer questions posed by Barát and Wood in 2008: (i) σ(Cn) = 4 whenever n ≥ 4 and n ∈/{5, 7};(ii) ρ(Pn) = 3 if 3 ≤ n ≤ 21 and ρ(Pn) = 4 otherwise;and (iii) ρ(Cn) = 4, whenever n ∈/{3, 4, 6, 8}, and ρ(Cn) = 3 otherwise. In particular, (ii) improves bounds on n obtained by Tao in *** Codes 05C15, 05C38 Copyright © 2023, The Authors. All rights reserved.

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Fiber-reinforcement effect on the mechanical behavior of reclaimed asphalt pavement–powdered rock–Portland cement mixtures

Transportation Engineering

引用

Transportation engineering 2022年 9卷

作者： Pasche, Eduardo Bruschi, Giovani Jordi Specht, Luciano Pivoto Aragão, Francisco Thiago Sacramento Consoli, Nilo Cesar Research Fellow Graduate Program in Civil Engineering Universidade Federal do Rio Grande do Sul RS Porto Alegre90035-190 Brazil Graduate Program in Civil Engineering Universidade Federal do Rio Grande do Sul RS Porto Alegre90035-190 Brazil Graduate Program in Civil Engineering Universidade Federal de Santa Maria RS Santa Maria97105-900 Brazil Graduate Program in Civil Engineering Universidade Federal do Rio de Janeiro RJ Rio de Janeiro21941-594 Brazil Professor of Civil Engineering Graduate Program in Civil Engineering Universidade Federal do Rio Grande do Sul RS Porto Alegre90035-190 Brazil

The milling of asphalt pavements has been extensively applied as a restoration technique, however, a large quantity of reclaimed asphalt pavement (RAP) waste is generated during this process. Numerous applications have been developed for the reutilization RAP, yet, these approaches are still not based on a rational criterion methodology for cemented soils, especially for fiber-reinforced ones. The goal of this research was to analyze the effect of fiber reinforcement on the mechanical behavior of reclaimed asphalt pavement–powdered rock–Portland cement mixtures, while proposing a rational dosage methodology through the porosity/cement content index (η/Civ). Resilient modulus, split tensile strength, and durability tests were conducted in non-reinforced and fiber-reinforced mixtures. Results have shown that non-reinforced mixtures depicted higher resilient modulus, split tensile strength, and durability when compared to fiber-reinforced ones, implying that fiber addition only hindered the mechanical properties of the specimens. This was associated with the length and diameter of the fiber along with the grain size and particle shape of the reclaimed asphalt pavement. Finally, the η/Civ index was shown to be an appropriate dosage methodology to predict the mechanical behavior of both non-reinforced and fiber-reinforced mixtures. © 2022

关键词： Porosity

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development of an Escherichia coli optical biosensor with computational validation 5

Development of an Escherichia coli optical biosensor with co...

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5th International Conference on Applications of Optics and Photonics, AOP 2022

作者： Dante, A. Silva, P.H. Lopes, R. Allil, A. Sbano, A. Esteves, M.E. Silva, M. Werneck, M. Allil, R. Departamento 1Integrated Micro and Nanotechnologies Group International Iberian Nanotechnology Laboratory Braga Portugal Photonics and Instrumentation Laboratory Electrical Engineering Program Universidade Federal Do Rio de Janeiro COPPE/UFRJ RJ Brazil Instituto Nacional de Metrologia Qualidade e Tecnologia Duque de Caxias Rio de Janeiro Brazil Instituto Oswaldo Cruz - IOC/Fiocruz Rio de Janeiro Brazil Instituto de Biodiversidade e Sustentabilidade -NUPEM/UFRJ- Rio de Janeiro Macaé Brazil

The biosensor consists of an optical sensing system and an optoelectronic data acquisition system. The sensor's optical system consists of a biochemically functionalized polymer optical fiber (POF-Plastic Optical Fiber) based on Field Evanescent technology. The Evanescent Field technique has been widely adopted in sensing and in this project, it was obtained by bending the fiber in a "U"shape, aiming to increase the sensitivity of the biosensor, through the contact of the curved sensor part with the sample biological. A data acquisition system was developed through an optoelectronic project aiming to increase the sensitivity when compared to a commercial equipment acquisition system. This work presents a biosensor for the detection of Escherichia coli based on an evanescent field with a polymer optical fiber linked to the analog signal acquisition system through an optoelectronic system developed. The interaction investigation of antibodies and antigens in Escherichia coli for computational methods was carried out in order to obtain information about the action of the antibody and in future steps applied in the validation of the diagnostic method. © Published under licence by IOP Publishing Ltd.

关键词： Escherichia coli

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Evaluation of the Optimal Performance of Modicon and Modicon+Varicol Simulated Moving Bed Variants

SSRN

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SSRN 2022年

作者： Supelano, Reinaldo Calderón Barreto, Amaro Gomes Secchi, Argimiro Resende Chemical Engineering Program COPPE Universidade Federal do Rio de Janeiro Centro de Tecnologia Bloco G Cidade Universitária Ilha do Fundão Rio de Janeiro Brazil School of Chemistry Universidade Federal do Rio de Janeiro Centro de Tecnologia Cidade Universitária Bloco E Ilha do Fundão Rio de Janeiro Brazil

The interest in the simulated moving bed (SMB) technology lies in its variants. Some of them that have a high potential to increase the performance in enantioseparations are the ModiCon and the ModiCon+VariCol. These variants are based on the modulation of feed concentration and a combination of feed concentration and length of zones modulations. The concept of the ModiCon process in the literature is that it can be applied only for systems described by nonlinear isotherms. However, there are no numerical or experimental studies that prove that. On the other hand, the hybrid operation of ModiCon+VariCol can be used in systems with a low number of columns due to the flexibility in the use of columns, but it has been little explored. In this work, the maximal performance of the ModiCon process was compared with the SMB process for a linear isotherm. Additionally, the ModiCon+VariCol process was evaluated in systems with a low number of columns. The enantioseparation of guaifenesin was considered as a case study. The result shows that the ModiCon process can also be applied with high performance in systems described by linear isotherms. In the evaluation of the ModiCon+VariCol process for unequal product purity, it was found that the hybrid operation with 3 columns showed a higher throughput and productivity than the SMB process with 6 columns. The productivity of the ModiCon+VariCol was more than three times higher than the conventional operation. © 2022, The Authors. All rights reserved.

关键词： Modulation

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A New Formulation for the Concerted Alchemical Calculation of van der Waals and Coulomb Components of Solvation Free Energies

arXiv

引用

arXiv 2022年

作者： Correa, Gabriela B. Maciel, Jéssica C.S.L. Tavares, Frederico W. Abreu, Charlles R.A. Chemical Engineering Program Instituto Alberto Luiz Coimbra de Pós-Graduação e Pesquisa em Engenharia Universidade Federal do Rio de Janeiro RJ Rio de Janeiro21941-909 Brazil Chemical Engineering Department Escola de Química Universidade Federal do Rio de Janeiro RJ Rio de Janeiro21941-909 Brazil

Alchemical free energy calculations via molecular dynamics have been widely used to obtain thermodynamic properties related to protein-ligand binding and solute-solvent interactions. Although soft-core modeling is the most common approach, the linear basis function (LBF) methodology [Naden, L. N.;et al. J. Chem. Theory Comput. 2014, 10 (3), 1128;2015, 11 (6), 2536] has emerged as a suitable alternative. It overcomes the end-point singularity of the scaling method while maintaining essential advantages such as ease of implementation and high flexibility for postprocessing analysis. In the present work, we propose a simple LBF variant and formulate an efficient protocol for evaluating van der Waals and Coulomb components of an alchemical transformation in tandem, in contrast to the prevalent sequential evaluation mode. To validate our proposal, which results from a careful optimization study, we performed solvation free energy calculations and obtained octanol-water partition coefficients of small organic molecules. Comparisons with results obtained via the sequential mode using either another LBF approach or the soft-core model attest to the effectiveness and correctness of our method. In addition, we show that a reaction field model with an infinite dielectric constant can provide very accurate hydration free energies when used instead of a lattice-sum method to model solute-solvent electrostatics. Copyright © 2022, The Authors. All rights reserved.

关键词： Molecular dynamics

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PC-Gym: BENCHMARK ENVIRONMENTS FOR PROCESS CONTROL PROBLEMS

arXiv

引用

arXiv 2024年

作者： Bloor, Maximilian Torraca, José Sandoval, Ilya Orson Ahmed, Akhil White, Martha Mercangöz, Mehmet Tsay, Calvin Chanona, Ehecatl Antonio del rio Mowbray, Max Department of Chemical Engineering Imperial College London LondonSW7 2AZ United Kingdom Department of Computing Imperial College London LondonSW7 2AZ United Kingdom School of Chemistry Universidade Federal do Rio de Janeiro Rio de Janeiro21941-909 Brazil Department of Computing Science University of Alberta Canada

PC-Gym is an open-source tool for developing and evaluating reinforcement learning (RL) algorithms in chemical process control. It features environments that simulate various chemical processes, incorporating nonlinear dynamics, disturbances, and constraints. The tool includes customizable constraint handling, disturbance generation, reward function design, and enables comparison of RL algorithms against Nonlinear Model Predictive Control (NMPC) across different scenarios. Case studies demonstrate the framework’s effectiveness in evaluating RL approaches for systems like continuously stirred tank reactors, multistage extraction processes, and crystallization reactors. The results reveal performance gaps between RL algorithms and NMPC oracles, highlighting areas for improvement and enabling benchmarking. By providing a standardized platform, PC-Gym aims to accelerate research at the intersection of machine learning, control, and process systems engineering. By connecting theoretical RL advances with practical industrial process control applications, offering researchers a tool for exploring data-driven control solutions. © 2024, CC BY-SA.

关键词： Reinforcement learning

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Millimeter-Scale Leak detection Using Distributed Acoustic and Temperature Gradient Sensing

Millimeter-Scale Leak Detection Using Distributed Acoustic a...

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IEEE SENSORS

作者： Guilherme H. Weber Danilo F. Gomes Eduardo N. dos Santos Ana L. B. Santana Jean C. C. da Silva Cicero Martelli Daniel R. Pipa Rigoberto E. M. Morales Sérgio T. C. Manoel F. da Silva Marco J. da Silva Graduate Program in Electrical and Computer Engineering Universidade Tecnológica Federal do Paraná Curitiba Brazil Multiphase Flow Research Center Universidade Tecnológica Federal do Paraná Curitiba Brazil Petrobras Rio de Janeiro Brazil Johannes Kepler University Linz Linz Austria

The occurrence of leaks in the transport of fluids in the oil and gas industry is a recurring problem. Compounds subject to reactions with the environment flowing under high pressure and temperature, through long pipes in places of difficult access exposed to the weather create several conditions for leaks. Distributed Acoustic Sensing (DAS) technology perfectly addresses those challenges as it provides long-range remote sensing through a dense network of sensors with high sensitivity and wide frequency response. In this work, we demonstrate the use of a DAS system simultaneously operating in acoustic and temperature gradient modes to detect a 1 mm diameter hole leak in a 1 inch-pipeline under water-air slug flow. The measurement data demonstrate the effects of the leakage in both acoustic and thermal perspectives. The results determine the system's ability to identify the integrity of the pipeline, as well as the exact moment the leak started, its location, characteristics in both time and frequency domain, and thermal effects as well. This research contributes to advance DAS technology as a sensing tool capable of detecting mm-sized leak hole in fluid transport pipelines.

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Performance of the SegNet in the Segmentation of Breast Ultrasound Lesions

Performance of the SegNet in the Segmentation of Breast Ultr...

引用

Pan American Health Care Exchanges, PAHCE

作者： P. O. Vianna R. Farias W. C. A. Pereira Biomedical Engineering Program COPPE/Federal University of Rio de Janeiro RJ Brazil Systems and Computing Engineering Program COPPE/Federal University of Rio de Janeiro RJ Brazil

ISBN: (纸本)9781728170558

This work presents a performance analysis of a convolutional neural network (CNN), named SegNet, applied for automatic segmentation of breast ultrasound images. defining the viability of CNN's could help with feature extraction and posterior classification of lesions, causing a decrease in the number of unnecessary biopsies. The breast ultrasound (BUS) dataset consists of 2054 images from 659 female patients, and each image was manually segmented by an experienced radiologist. The dataset is fed into the CNN without any filtering process applied to it and the test output is then compared with the radiologist's labels. We compared the results of different loss and activation functions, and the experiments reveal that the best performance was achieved using dice loss function, with dice coefficient of 81.1%.

关键词： Image segmentation Ultrasonic imaging Medical services Breast Feature extraction Generative adversarial networks Performance analysis

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