Starch-PVA based films with Clitoria ternatea flower extract: Characterization, phenolic compounds release and compostability João Vítor do Nascimento, Kaylaine Amorim Silva, Vanessa Cipriani Giuliangeli, Ane Louise Dionizio Mendes, Lorena Paloma Piai, Roger Nabeyama Michels, Tatiane Cristina Dal Bosco, Gylles Ricardo Ströher, Marianne Ayumi Shirai International Journal of Biological Macromolecules, 2024 The kinetic release of phenolic compounds from biodegradable films with Clitoria ternatea flower extract (ECT) in different food-simulant fluids and compostability were evaluated for the first time. This work aimed to incorporate ECT in starch-PVA-based film formulations, and the antioxidant capacity, total phenolic compounds, opacity, color, mechanical properties, compostability, and polyphenol release in different fluid simulants were determined. The results obtained showed that antioxidant activity and the total phenolic compounds were ECT dose dependent. Due to its antioxidant properties, ECT interfered with the film's composting process, reaching an average weight loss of 70 %. Additionally, the addition of ECT interfered with the mechanical properties, reducing the tensile strength, probably due to the plasticizer effect. The type of simulating fluid influenced the release of polyphenols from the films, and the presence of water favored the release because it hydrated and swelled the starch-PVA matrix, facilitating diffusion. The classic zero- and first-order models were the most effective in describing the release kinetics of polyphenols from the films. The results of this study demonstrate that the antioxidant potential and the release of polyphenols from starch-PVA-based films in different simulated fluids allow their application in active packaging, making them a sustainable alternative for food preservation.
A multigrid Waveform Relaxation Method for solving the Pennes bioheat equation Cosmo D. Santiago, Gylles R. Ströher, Marcio A. V. Pinto, Sebastião R. Franco Numerical Heat Transfer Part A Applications, 2023 This work proposes a multigrid Waveform Relaxation Method (WRMG) that uses the finite difference method for the discretization to solve Pennes’ bioheat equation. There is no evidence in the literature of using the WRMG to solve this equation. The proposed algorithm is based on the red-black Gauss-Seidel smoother in space and the line Gauss-Seidel smoother in time. Verification of code is presented. The performance analysis of the multigrid method confirms the convergence and efficiency of the algorithm. The method, which favors parallel architecture, is tested in two-dimensional numerical experiments on an academic problem and for the thermal analysis of human skin.
Generalization of the integral and differential method for analysis of rate data by means of the fractional calculus Gylles Ricardo Ströher, Gisely Luzia Ströher Canadian Journal of Chemical Engineering, 2022 The kinetic study of chemical reactions is usually carried out by means of analysis of experimental rate data obtained during the evolution of a reaction in a batch reactor. The methods for analysis of rate data obtained in a batch reactor include the classical integral methods (CIM) and classical differential methods (CDM), which use temporal derivatives of the unit‐order concentration, dCA/dt, in the mass balance equation. The present study proposes these two methods of analysis in a generalized formulation that makes use of non‐integer order temporal derivatives, dαCA/dtα, 0<α ≤ 1, called generalized integral method (GIM) and generalized differential method (GDM) in the present work. The solutions of the fractional ordinary differential equations (FODE) of GIM are presented using the Laplace transform technique and numerical fractional derivative evaluation methods for GDM application. The proposed generalized methods allow for the determination of the order and the specific reaction rate in the same way as the classical methods, that is, of integer order (α = 1); however, generalized methods have the additional advantage of determining the fractional order of the temporal derivative.
Assessment of thermal models for human eye Gylles Ricardo Ströher, Cláuda Regina de Andrade, Gisely Luzia Ströher Heat and Mass Transfer Waerme Und Stoffuebertragung, 2020
Numerical two-dimensional thermal analysis of the human skin using the multigrid method Gylles Ricardo Stroher, Cosmo Damião Santiago Acta Scientiarum Technology, 2020 Heat can be used as an adjuvant treatment of many diseases and also as a powerful tool to help diagnose cancers, with the advantage to be a noninvasive exam. Some tumors may be best diagnosed by evaluating body temperature distribution, for instance, it is observed that local temperatures of the skin over a tumor are higher than the average skin temperature. Certainly, it is expected from medical diagnostics to be, early, fast and very precise. Especially if the health problem is a tumor, it is necessary to know the shape and the size of the cancer. Thermal images can provide further information about the tumor, generally, the thermal diagnostic is made comparing images of the region with a bioheat model. In this context, the present study shows interesting results about the multigrid method applied to solve the Pennes bioheat equation in two dimensions, using a non-stationary and steady state cases for the skin heath and with melanoma. The multigrid method presented itself as an extremely efficient and fast tool to solve the bioheat equation with refined grids that provide good spatial precision.
Capture of Co2 in activated carbon synthesized from municipal solid waste compost M. Karimi, L.F.A.S. Zafanelli, J.P.P. Almeida, J.A.C. Silva, A.E. Rodrigues, G.R. Ströher Wastes Solutions Treatments and Opportunities III Selected Papers from the 5th International Conference Wastes Solutions Treatments and Opportunities 2019, 2020 In this study, municipal solid waste composts obtained from mechanical biological treatment has been considered as a source of adsorbents for CO2 capture. Three samples derived from the maturated compost in the municipal solid wastes were modified to produce activated carbon. The first sample was treated with sulfuric acid, the second one was thermally treated at 800°C and the last one was modified chemically and thermally with sulfuric acid and at 800°C. Then, the CO2 uptake capacity of prepared samples was measured through breakthrough adsorption experiments at the post combustion operational conditions to collect isotherm data. Also a fixed bed adsorption mathematical model was developed by applying mass and energy balances. Results showed the municipal solid wastes have an excellent capacity to be considered as source of adsorbent for CO2 capture also the mathematical model is able to predict breakthrough data.
Explaining trans geometric isomerism through a board game with a focus on food and trans fat Journal of Science Education, 2017
