23 documents found, page 1 of 3
Machine Learning model for the prediction of self-diffusion coefficients in liq...
Dias, Andreia F. .F.; Portugal, Inês; Aniceto, José P. S.; Silva, Carlos M.Machine Learning (ML) models were developed in this work to predict self-diffusion coefficients (D11) of dense fluids using four training algorithms: Gradient Boosting, k-Nearest Neighbors, Decision Tree, and Random Forest. A database of 7931 experimental points from 223 substances, at different pressures and temperatures, was used to train the models. From an initial set of 34 input features (variables/propert...
Obtaining value from wine wastes: paving the way for sustainable development
Evtyugin, Dmitry; Aniceto, José P. S.; Marques, Rita; Portugal, Inês; Silva, Carlos Manuel; Serafim, Luísa S.; Xavier, Ana M. R. B.Winemaking is one of the main Portuguese industries and has significantly grown in recent years, thus increasing the quantity of obtained residues. These wastes have a complex chemical composition and structure, and, for this reason, their treatment and valorisation are simultaneously a challenge and an opportunity. After an overview of the wine industry and its wastes, this article intends to review the differ...
Diffusivities of ketones and aldehydes in liquid ethanol by molecular dynamics ...
Zêzere, Bruno; Portugal, Inês; Silva, Carlos M.; Gomes, José R.B.The tracer diffusion coefficients of six ketones (propanone, butanone, pentan-2-one, pentan-3-one, hexan-2-one, hexan-3-one) and six aldehydes (methanal, ethanal, propanal, butanal, pentanal and hexanal) in liquid ethanol were computed by classical molecular dynamics (MD) simulations over 303.15-333.15 K and 1-150 bar. The calculated tracer diffusion coefficients, D12, compared very satisfactorily with experime...
Diffusion coefficients of bioactive compounds in sub/supercritical CO2 and CO2/...
Zêzere, Bruno; Rios, William Q.; Portugal, Inês; Silva, Carlos M.; Gomes, José R.B.A computational strategy based on molecular dynamics (MD) simulations is proposed for the 14 prediction of tracer diffusion coefficients of bioactive compounds in CO2 ( ) and CO 12 2 modified 15 with ethanol ( ), in both supercritical and subcritical regions. Three systems were used for its m,i 16 validation, namely, β-carotene and ibuprofen in supercritical CO2, and gallic acid in CO2 modified 17 with 16 mol.%...
Economic analysis of the supercritical fluid extraction of lupane-triterpenoids...
Rodrigues, Vítor H.; Portugal, Inês; Silva, Carlos M.The supercritical fluid extraction of Acacia dealbata Link. bark was performed with carbon dioxide at different pressures (10–30 MPa), temperatures (40–80 °C), and cosolvents contents (0–10 wt% of ethyl acetate or ethanol) to analyse their effect on various performance indicators whose best values were: total extraction yield of 1.57 wt%; lupenyl acetate (LA) and lupenone (Lu) extraction yields of 777.5 mg kgba...
Modeling tracer diffusion coefficients of any type of solutes in polar and non-...
Zêzere, Bruno; Portugal, Inês; Gomes, José R. B.; Silva, Carlos M. Send mail to Silva C.M.In this work, a simple two-parameters correlation based on the Rice and Gray, Lennard-Jones, and Stockmayer theories was devised for the calculation of binary diffusion coefficients (D12) of any type of solutes at infinite dilution in polar and non-polar solvents. This equation can be relevant for systems with polar solvents, since most models in the literature fail when strong intermolecular forces predominate...
Diffusivities of linear unsaturated ketones and aldehydes in compressed liquid ...
Zêzere, Bruno; Buchgeister, Simon; Faria, Sofia Neto; Portugal, Inês; Gomes, José R. B.; Silva, Carlos M.For the accurate design, optimization and simulation of chemical processes limited by mass transfer kinetics it is important the knowledge of transport properties, namely, diffusion coefficients, D12. In this work, the D12 values of six unsaturated linear ketones (i.e., propanone, butanone, propan-2-one, propan-3-one, hexan-2-one and hexan-3-one) and three unsaturated linear aldehydes (i.e., butanal, pentanal a...
Revisiting Tracer Liu-Silva-Macedo model for binary diffusion coefficient using...
Zêzere, Bruno; Portugal, Inês; Gomes, José R.B.; Silva, Carlos M.This work compiles the largest database of tracer diffusion coefficients (D12) containing 6180 experimental points from 331 non-polar and weakly polar liquid and supercritical systems. Then, the Tracer Liu − Silva − Macedo (TLSM) model and its 1-parameter correlations (TLSMd and TLSMen) are evaluated using this database, taking into account the importance of phenomenological and reliable equations for D12 estim...
Diffusion of quercetin in compressed liquid ethyl acetate and ethanol
Zêzere, Bruno; Iglésias, João; Portugal, Inês; Gomes, José R.B.; Silva, Carlos ManuelSupercritical fluids are alternatives to conventional harmful organic compounds. In the case of supercritical fluid extraction, CO2 is the most common solvent and can be advantageously modified with small contents of co-solvents like ethanol and ethyl acetate. The rigorous estimation of the tracer diffusion coefficients (D12) of solutes in supercritical mixtures (CO2 + co-solvent) requires their individual D12 ...
Calcificação Caseosa do Ânulo da Válvula Mitral: a propósito de um caso clínico
Rebelo, João Manuel; Carvalho, André; Portugal, Inês; Cunha, RuiA calcificação caseosa do ânulo da válvula mitral resulta da degeneração crónica do seu anel valvular fibroso que se apresenta sob a forma de calcificação caseosa. Esta representa uma variante rara e idiopática, cujo desconhecimento pode levar a diagnósticos equívocos. Os autores apresentam um caso clínico de calcificação caseosa do ânulo da válvula mitral, incluindo os seus principais achados imagiológicos e d...