Sustainable Valorization of Coffee Husk for Fungal Cellulase Production and Biomass Saccharification Patrícia Garcia Vasconselos, Rafaela Inês de Souza Ladeira Ázar, Julio Cesar Dutra Sampaio, Gabriela Piccolo Maitan‐Alfenas, Jussara Moreira Coelho, Wellington Betencurte da Silva Environmental Quality Management, 2026 Cellulases are essential enzymes for breaking down lignocellulosic biomass in second‐generation ethanol production, but their high cost limits widespread use. Solid‐state fermentation (SSF) offers a cost‐effective alternative by producing high enzyme yields from agro‐industrial residues. This study investigated cellulase production by Aspergillus fumigatus using coffee husks, both untreated and pretreated via combined alkaline and microwave methods, as carbon sources. The effects of initial moisture (50%–70%) and husk content (60%–80%) on SSF were optimized through response surface methodology. The crude enzymatic extract was biochemically characterized for optimal pH (3–8), temperature (30–70°C), thermal stability, and metal ion effects. Pretreated husks increased enzyme activity (FPase) by 121%, confirming improved cellulose accessibility. The extract showed optimal activity at pH 5–6, stability between 40°C and 60°C, and enhanced performance with Cu 2 + , Co 2 + , and Mn 2 + . When applied to hydrolysis of pretreated coffee husks, the extract achieved 27 mg/g conversion after 48 h, demonstrating its effectiveness. These results indicate that coffee husk serves both as an inducer of fungal cellulase production and as a lignocellulosic feedstock, emphasizing its biotechnological potential for sustainable biomass valorization.
A combined Physics-informed neural network and particle filter approach to solve a state estimation problem during the heating of a nanofluid Wancley Oinhos Pedruzzi, Carlos Eduardo Rambalducci Dalla, José Mir Justino Costa, Nilton Pereira da Silva, Helcio Rangel Barreto Orlande, Wellington Betencurte da Silva, Julio Cesar Sampaio Dutra Numerical Heat Transfer Part B Fundamentals, 2026 Hyperthermia has been attracting great attention, research resources and clinical translation efforts as a cancer treatment. Metallic nanoparticles can enhance heat deposition in tumors when subjected to external energy sources like lasers. However, challenges remain in accurately estimating state variables, such as the temperature and heat sources, during treatments. This study presents a combined Physics-Informed Neural Network (PINN) and particle filter approach for state estimation in a model, representing a sample of a nanofluid heated by a near-infrared diode laser. The PINN is trained to solve the heat transfer model and serve as the state evolution model in the particle filter. Synthetic and actual temperature measurements from heating experiments involving a nanofluid of palladium-cerium oxide nanoparticles are used in the solution of the state estimation problem. Verification tests show that the particle filter can robustly estimate states with 850 particles in few seconds of computational time, due to the efficient PINN predictions. Overall, the combined PINN - particle filter approach demonstrates potential for solving state estimation problems in complex engineering systems, such as in cancer thermotherapy.
Simulating Paraffin Wax Deposit Removal: A Numerical Study of SGN Application Rafael Cavalcante, Julio Cesar Dutra, Luiz Alberto Abreu, Diego Estumano, Evaldiney Monteiro, et al. Journal of Applied and Computational Mechanics, 2025 Offshore oil exploration encounters numerous challenges, the formation of paraffin wax deposits ranks among them. The Nitrogen Generating System (SGN) emerges as a hybrid technique, utilizing a thermochemical reaction with nitrogen salts to generate heat and facilitate the melting of paraffin wax deposit. Given the substantial heat release during this reaction, a meticulous approach is imperative to prevent potential damage to the oil pipeline. This study focuses on the numerical simulation of an SGN application, addressing the heat conduction problem, by solving a transient two-dimensional heat conduction model with phase change and chemical reaction. Approximately 70% of paraffin deposit was removed after 3 hours of SGN application. After 5 hours of SGN simulation, with a pH level of 4 and initial concentration of 2 mol/l, a liquid fraction of paraffin wax of 0.9 was observed. This result is consistent with other studies, such as thermal washing and active electrical heating techniques. The dynamic behavior of the liquid fraction obtained in simulation also aligns with previous works, showing a nonlinear and decreasing rate of melted paraffin wax. The SGN simulation identified a phenomenon called “heat spike”, in which the chemical reactants are quickly consumed, leading to a sudden temperature increasing. This effect is significantly influenced by the pH level and initial concentration. The findings offer valuable insight into the efficacy of the SGN technique in mitigating paraffin-related issues, highlighting the importance of precise control over reaction variables for optimal results.
Internal Heat Flux Estimation in Tubes Using the Backward Reciprocity Functional Method: Numerical and Experimental Results Bruno Henrique Marques Margotto, Carlos Eduardo Polatschek Kopperschmidt, Marcelo José Colaço, Wellington Betencurte da Silva, Fabio Bozzoli, Luca Cattani, Luca Pagliarini Heat Transfer Engineering, 2025 Directly measuring internal heat fluxes in pipes is often impractical, requiring inverse heat conduction problem solutions for a nonintrusive and accurate assessment. This study extends the non-iterative backward reciprocity functional method to estimate time- and space-varying heat fluxes in tubes. To reduce computational cost, the classical integral transform technique is applied to take advantage of the orthogonality between the eigenfunctions and orthonormal basis in the spatial domain. Initially, the method uses synthetic temperature measurements on the exterior surface of a pipe, generated by solving the forward problem for different known heat fluxes on the internal surface of the pipe and adding Gaussian noises to the temperature data. Then, the method is applied to data from pulsating heat pipes experiments, where the fluid inside the tubes shows oscillatory variations over time and space. The pulsating heat pipe operation is strongly correlated with the internal wall heat flux, indicating its working condition, such as the startup and dry-out conditions. The results demonstrate good accuracy in assessing the heat flux with low computational costs using synthetic and experimental data. The total computational time for the estimate using experimental data was 4 s with a code written in MATLAB, which can be reduced to a fraction of a second when using a compiled language, such as C or C++.
Parameter Estimation of Breakthrough Curve Models in the Adsorption Process of H2S and CO2 Using the Markov Chain Monte Carlo Method Haianny Beatriz Saraiva Lima, Ana Paula Souza de Sousa, Wellington Betencurte da Silva, Deibson Silva da Costa, Emerson Cardoso Rodrigues, Diego Cardoso Estumano Applied Sciences Switzerland, 2024 The increase in emissions of toxic gasses such as hydrogen sulfide (H2S) and carbon dioxide (CO2), resulting from growing urbanization and industrialization, has caused environmental and public health problems, making the implementation of air purification techniques through adsorption important. Thus, modeling the gas adsorption process is fundamental for good agreement with experimental data, employing mathematical models that enable the prediction of adsorption capacity. In this way, the present work aimed to compare different analytical breakthrough curve models (Thomas, Yoon–Nelson, Adams–Bohart, and Yan) for the adsorption of H2S and CO2 in fixed-bed columns, using experimental data from the literature, estimating the curve parameters through the Markov Chain Monte Carlo (MCMC) method with the Metropolis–Hastings algorithm, and ranking using the determination coefficients (R2 and R2Adjusted) and the Bayesian Information Criterion (BIC). The models showed better agreement using the estimation of maximum adsorption capacity (qs, N0) and the constants of each model (kth, kyn, and kba). In the adsorption of H2S, the Yan model stood out for its precision in estimating qs. For the adsorption of CO2, the Adams–Bohart model achieved better results with the estimation of N0, along with the Yoon–Nelson model. Furthermore, the use of this method allows for a reduction in computational effort compared to models based on complex differential equations.
A particle-filter based framework for inverse problems using ansys fluent and python International Symposium on Advances in Computational Heat Transfer, 2021
Sequential boundary heat flux estimation using the method of fundamental solutions and bayesian filters International Symposium on Advances in Computational Heat Transfer, 2021
Particle filter-model predictive control for oil reservoir management International Symposium on Advances in Computational Heat Transfer, 2021
A combined Physics-informed neural network and particle filter approach to solve a state estimation problem during the heating of a nanofluid W Oinhos Pedruzzi, CER Dalla, JMJ Costa, NP da Silva, HRB Orlande, ... Numerical Heat Transfer, Part B: Fundamentals 87 (1), 2531244 , 2026 2026
Nonintrusive thermal contact conductance estimation in double-layered pipelines: a reciprocity functional method perspective CEP Kopperschmidt, BHM Margotto, MJ Colaço, WB da Silva Numerical Heat Transfer, Part A: Applications 87 (1), 2364059 , 2026 2026 Citations: 2
Prediction of Temperature and Moisture Concentration in Autoclave-Cured Epoxy Resin Using Physics-Informed Neural Networks WO Pedruzzi, IF Tosi, WPM Quiroz, R D'Elia, JCS Dutra, WB da Silva Defect and Diffusion Forum 451, 75-85 , 2026 2026
A meshless Schwarz-MFS framework for identifying time-dependent thermal contact conductance in layered materials IF Tosi, LA da Silva Abreu, JCS Dutra, WB da Silva Engineering Analysis with Boundary Elements 185, 106649 , 2026 2026
Meshless Transient Thermal Modeling of Polymer Composite Curing with Exothermic Heat Generation IF Tosi, W Pedruzzi, WPM Quiroz, R D'Elia, JCS Dutra, W da Silva Defect and Diffusion Forum 451, 87-94 , 2026 2026
Internal Heat Flux Estimation in Tubes Using the Backward Reciprocity Functional Method: Numerical and Experimental Results BHM Margotto, CEP Kopperschmidt, MJ Colaço, WB Silva, F Bozzoli, ... Heat Transfer Engineering, 1-23 , 2025 2025
Pipeline Heating Analysis Using the Method of Fundamental Solutions: A Computational Approach IF Tosi, WB da Silva, JCS Dutra XLVI Ibero-Latin American Congress on Computational Methods in Engineering 5 , 2025 2025
Estimating thermal contact conductances in two-layer cylindrical composites using the reciprocity functional method and transient measurements CEP Kopperschmidt, BHM Margotto, MJ Colaço, WB da Silva Journal of the Brazilian Society of Mechanical Sciences and Engineering 47 … , 2025 2025 Citations: 3
ON THE ENTHALPY METHOD FOR SOLVING MOVING BOUNDARY PROBLEMS R Cavalcante, WB da Silva, JCS Dutra, ER Monteiro Revista Mundi Engenharia, Tecnologia e Gestão (ISSN: 2525-4782) 9 (4) , 2024 2024
Simulating Paraffin Wax Deposit Removal: A Numerical Study of SGN Application RF Cavalcante, JCS Dutra, LAS Abreu, DC Estumano, ER Monteiro, ... Journal of Applied and Computational Mechanics, 1-9 , 2024 2024 Citations: 1
Parameter Estimation of Breakthrough Curve Models in the Adsorption Process of H 2 S and CO 2 Using the Markov Chain Monte Carlo Method HBS Lima, APS Sousa, WB Silva, DS Costa, EC Rodrigues, ... Applied Sciences 14 (16), 6956 , 2024 2024 Citations: 5
Exploring Digital Twins of Nonlinear Systems through Meta-Modeling with Echo State Networks LCJCJ Campos, ACSR Dias, WB da Silva, JCS Dutra Latin-American Journal of Computing 11 (2), 13-22 , 2024 2024 Citations: 1
An Eulerian–Lagrangian method of fundamental solutions for the advection–diffusion equation with time dependent coefficients CER Dalla, WB da Silva, JCS Dutra, MJ Colaco Engineering Analysis with Boundary Elements 164, 105766 , 2024 2024 Citations: 2
Online estimation of inlet contaminant concentration using Eulerian-Lagrangian method of fundamental solutions and Bayesian inference CER Dalla, WB da Silva, JCS Dutra, MJ Colaço Computers & Mathematics with Applications 164, 131-138 , 2024 2024 Citations: 7
Monitoring internal heat fluxes on Pulsating Heat Pipes using Kalman filter–Numerical and experimental results BHM Margotto, CEP Kopperschmidt, MJ Colaço, WB Da Silva, F Bozzoli, ... Applied Thermal Engineering 245, 122801 , 2024 2024 Citations: 4
Physics-Informed Neural Network for monitoring the sulfate ion adsorption process using particle filter WO Pedruzzi, CER Dalla, WB SILVA, D Guimaraes, VA Leão, JCS Dutra Anais da Academia Brasileira de Ciências 96, e20240262 , 2024 2024
Estimation of Internal Heat Flux on Pulsating Heat Pipes using Kalman Filter: Numerical and Experimental Results BHM Margotto, MJ Colaço, CEP Kopperschmidt, F Bozzoli, L Pagliarini, ... Journal of Physics: Conference Series 2685 (1), 012071 , 2024 2024 Citations: 1
Echo state network-based metamodel for the problem of stagnant petroleum cooling in pipe-in-pipe flowlines AAR da Silva Graciano, FJ da Silva Fortuna, WO Pedruzzi, ACSR Dias, ... Scientia Plena 19 (11) , 2023 2023
Selection of models and parameter estimation for monitoring the COVID-19 epidemic in Brazil via bayesian inference. LM Inez, CER Dalla, W Betencurte da Silva, JC Sampaio Dutra, ... Revista Ciência e Natura 45 , 2023 2023
ESTIMATION OF THERMAL CONTACT CONDUCTANCE IN DUCTS USING THE RECIPROCITY FUNCTIONAL APPROACH CEP Kopperschmidt, BHM Margotto, MJ Colaço, WB da Silva International Heat Transfer Conference Digital Library , 2023 2023
MOST CITED SCHOLAR PUBLICATIONS
State estimation problems in heat transfer HRB Orlande, MJ Colaço, GS Dulikravich, F Vianna, WB da Silva, ... International Journal for Uncertainty Quantification 2 (3) , 2012 2012 Citations: 53
Sequential particle filter estimation of a time-dependent heat transfer coefficient in a multidimensional nonlinear inverse heat conduction problem WB Da Silva, JCS Dutra, CEP Kopperschimidt, D Lesnic, RG Aykroyd Applied Mathematical Modelling 89, 654-668 , 2021 2021 Citations: 40
Application of two Bayesian filters to estimate unknown heat fluxes in a natural convection problem MJ Colaço, HRB Orlande, W B. da Silva, GS Dulikravich 2012 Citations: 38
Application of particle filters to regional-scale wildfire spread WB Da Silva, MC Rochoux, HRB Orlande, MJ Colaço, O Fudym, M El-Hafi, ... High Temperatures-High Pressures 43 (6), p. 415-440 , 2014 2014 Citations: 33
Model selection and parameter estimation in tumor growth models using approximate Bayesian computation-ABC JMJ da Costa, HRB Orlande, WB da Silva Computational and Applied Mathematics 37, 2795–2815 , 2017 2017 Citations: 30
Propylene polymerization reactor control and estimation using a particle filter and neural network ACSR Dias, WB da Silva, JCS Dutra Macromolecular Reaction Engineering 11 (6), 1700010 , 2017 2017 Citations: 23
Nonstationary bubble shape determination in electrical impedance tomography combining Gauss–Newton optimization with particle filter BF de Moura, MF Martins, FHS Palma, WB da Silva, JA Cabello, R Ramos Measurement 186, 110216 , 2021 2021 Citations: 20
Tutorial 10: Kalman and particle filters H Orlande HAL (Le Centre pour la Communication Scientifique Directe) , 2011 2011 Citations: 17
Design of a Low-Cost Acquisition System to Reconstruct Images through Electrical Resistance Tomography BF MOURA, MF MARTINS, F SEPULVEDA, WB Silva, JA CABELLO, ... IEEE Latin America Transactions 100 (1), 1-7 , 2021 2021 Citations: 15
Response surface methods applied to scarce and small sets of training points A comparative study MJ Colaço, WB Silva, AC Magalhães, GS Dulikravich EngOpt 2008-international conference on engineering optimization, Rio de … , 2008 2008 Citations: 13
Sequential estimation of the time-dependent heat transfer coefficient using the method of fundamental solutions and particle filters WB Da Silva, JCS Dutra, CEP Kopperschimidt, D Lesnic, RG Aykroyd Inverse Problems in Science and Engineering 29 (13), 3322-3341 , 2021 2021 Citations: 11
Particle filter-based monitoring scheme for simulated bio-ethylene production process LSF Salardani, LP Albuquerque, JMJ da Costa, WB da Silva, JCS Dutra Inverse Problems in Science and Engineering 27 (5), 648-668 , 2019 2019 Citations: 9
Evaluation of Bayesian filters applied to heat conduction problems WB Silva, HRB Orlande, MJ Colaço 2nd International Conference on Engineering Optimization , 2010 2010 Citations: 9
Sequential state inference of engineering systems through the particle move-reweighting algorithm R Marques, W Silva, R Hoffmann, J Dutra, F Coral Computational and Applied Mathematics 37 (Suppl 1), 220-236 , 2018 2018 Citations: 8
Aplicação de filtros de partículas para a assimilação de dados em problemas de fronteira móvel WB da Silva Institut National Polytechnique de Toulouse-INPT; Universidade federal do … , 2012 2012 Citations: 8
Online estimation of inlet contaminant concentration using Eulerian-Lagrangian method of fundamental solutions and Bayesian inference CER Dalla, WB da Silva, JCS Dutra, MJ Colaço Computers & Mathematics with Applications 164, 131-138 , 2024 2024 Citations: 7
Use of machine learning as a tool for determining fire management units in the brazilian atlantic forest RS JUVANHOL, NC FIEDLER, ARDOS SANTOS, TMO PELUZIO, ... Annals of the Brazilian Academy of Sciences 95, 1-20 , 2023 2023 Citations: 7
Estimation of Timewise Varying Boundary Heat Flux via Bayesian Filters and Markov Chain Monte Carlo Method WB Da Silva, JCS Dutra, DC Knupp, LAS Abreu, AJ Silva Neto Computational Intelligence in Emerging Technologies for Engineering … , 2020 2020 Citations: 7
A hybrid estimation scheme based on the sequential importance resampling particle filter and the particle swarm optimization (PSO-SIR) WB da Silva, JCS Dutra, JMJ Costa, LAS Abreu, DC Knupp, AJ Silva Neto Computational Intelligence, Optimization and Inverse Problems with … , 2018 2018 Citations: 7