Machine learning models for the prediction of diffusivities in supercritical CO2 systems

The molecular diffusion coefficient is fundamental to estimate dispersion coefficients, convective mass transfer coefficients, etc. Since experimental diffusion data is scarce, there is significant demand for accurate models capable of providing reliable diffusion coefficient estimations. In this work we applied machine learning algorithms to develop predictive models to estimate diffusivities of solutes in supercritical carbon dioxide. A database of experimental data containing 13 properties for 174 binary systems totaling 4917 data points was used in the training of the models. Five machine learning algorithms were evaluated and the results were compared with three commonly used classic models. The best results were found using the Gradient Boosted algorithm which showed an average absolute relative deviation (AARD) of 2.58 % (pure prediction). This model has five parameters: temperature, density, solute molar mass, solute critical pressure and solute acentric factor. For the same dataset, the classic Wilke-Chang equation showed AARD of 12.41 %. The developed model is provided as command line program.publishe

Enhanced separation of bioactive triterpenic acids with a triacontylsilyl silica gel adsorbent: from impulse and breakthrough experiments to the design of a simulated moving bed unit

A simulated moving bed (SMB) unit was designed to separate oleanolic and ursolic acids, two naturally occurring triterpenoids with structural isomerism, with remarkable nutraceutical and pharmacological properties. A triacontylsilyl silica gel adsorbent (stationary phase of an Acclaim C30 column) was considered and impulse tests with different solvents were performed to select a mobile phase, from which methanol/water 95/5 (%, v/v) emerged as the most suitable. Equilibrium and global mass transport coefficients were then determined through breakthrough experiments using pure compound solutions and the C30 column. Afterwards, these parameters were applied to the simulation of two model binary mixture separations, whose breakthrough curves were also experimentally measured. Finally, the SMB unit was designed and optimized. It was demonstrated that using the packing of an Acclaim C30 column and methanol/water 95/5 (%, v/v) as mobile phase it is possible to separate both acids with purities of 99.9 wt.%, a productivity of 1.705 kg/(m3adsorbent day), and a configuration of two columns per section (2–2–2–2). The simulated results obtained in this work with the C30 stationary phase represent a significant improvement over literature data.publishe

Reversed-phase chromatographic separation and downstream precipitation of lupane- and oleanane-type triterpenoids: experiments and modeling based on the method of moments

The reversed-phase chromatographic separation of two triterpenic acids (TTAs), betulinic and oleanolic acids, using a triacontyl (C30) stationary phase was addressed in this work. Methanol, water, acetonitrile, ethanol, isopropanol, ethyl acetate, acetone and mixtures thereof were tested, and the best mobile phase to conduct the separation was found to be methanol/acetonitrile 50/50 (%, v/v) at 23 °C, taking into account parameters like selectivity, resolution and TTAs solubility. The method of moments was used to determine the equilibrium constants of isotherms, the axial dispersion coefficients and the global linear driving force coefficients of pure betulinic and pure oleanolic acids. These parameters were then successfully validated by modeling unary and binary breakthrough curves. Simulated moving bed calculations showed that betulinic and oleanolic acids can be both obtained with purity of 99.2 % and productivity of 56.2 kg/(m3adsorbent day) using the packing material of an Acclaim C30 column with a 1-1-1-1 configuration with columns of 7.5 cm long. Finally, in order to recover the two TTAs from the SMB extract and raffinate streams, water was envisioned as a precipitation agent. Accordingly, the solubility of each TTA was measured in methanol/acetonitrile 70/30, 50/50, and 30/70 (%, v/v) modified with water. The obtained results showed that adding 65 % (%, v/v) of water it is possible to precipitate 98 % of the dissolved TTAs in all the tested methanol/acetonitrile mixtures.publishe

Application of the multivariate and univariate analyses to estimate the feed efficiency in beef cattle

This study aimed to compare the univariate analyses (relationship between dry matter intake (DMI) and average daily gain (ADG), Kleiber ratio, and residual feed intake) and multivariate analysis (bionutritional index [BNI]) to determine feed efficiency. Were used a total of 160 cattle (individual data) and the analyzed variables were dry matter intake, weight gain, and body weight of the animals. We used five methods to evaluate feed efficiency, the BNI, FE, corrected feeding efficiency (corFE), Kleiber ratio (KR), and residual feed intake (RFI).  Study 1 demonstrated that only the FE (p=0.0472) was significant, although the FE after the transformation of Box-Cox (corFE) (p=0.0642) showed a statistical trend. In studies 2, 3, and 5, we observed that BNI was the best biological efficiency indicator. In the study 4, we observed that the best indicators were FE (0.110; p=0.0281), corFE (0.380; p=0.0429), and RFI (0.465; p=0.0340) for the genders. However, corFE decreased the coefficient of variation in all studies. In conclusion, the use of the Box-Cox transformation is as efficient as the multivariate analysis in discriminating experimental groups (genetic groups, different levels of concentrate in the diet, and genders) concerning the other univariate analyzes

13th International Chemical and Biological Engineering Conference (CHEMPOR 2018): book of short abstracts

University of Aveiro and Ordem dos Engenheiros proudly welcome all participants to the 13th International Chemical and Biological Engineering Conference - CHEMPOR 2018. Welcome to Aveiro! During three days, from October 2nd to 4th, more than 370 participants from Industry and Academia gathered at Centro Cultural e de Congressos de Aveiro to discuss recent developments and future directions in different areas of chemical engineering, materials science and engineering, biotechnology and biological engineering. CHEMPOR 2018 aims to be a forum for the debate of societal challenges related to energy, the environment, and the efficient use of natural resources and materials, all of which require innovative solutions complying with sustainability criteria. In 2017 Portuguese exports increased circa 11 % reaching the highest value of the Gross Domestic Product (in a time horizon of 23 years). Portugal’s Ministry of Economy estimates that capital-intensive industries (such as chemicals and polymers producers) and manufacturing industries (including food, textile, paper, cork, wood panels and metal producers) account for over 50 % of the overall value of the exportations. In this context, CHEMPOR 2018 emerges as a privileged forum to discuss technological and scientific issues that will promote economic growth through innovation. The Organizing Committee accepted more than 345 communications, of which 83 oral presentations, after peer reviewing. Internationally recognized scientists were invited to deliver 6 Plenary Lectures and 6 Keynote Speeches. On the opening day of CHEMPOR 2018, the Portuguese Minister of Economy, Professor Manuel Caldeira Cabral, made a communication in the presence of dozens of industrial sponsors. Just before the closing session, the Professor Almiro Castro Award (sponsored by PARALAB) was granted , for the second time, and prizes were awarded to the best Oral and Poster Communications presented during the Conference. The Organizing Committee of CHEMPOR 2018 acknowledges all authors for their contributions, all colleagues involved in the organization of the program, and the generosity of all sponsors. We wish you a memorable Conference both scientifically and socially.publishe

Organização social profissional dos pescadores artesanais da foz do rio Amazonas, Amapá, Brasil

O trabalho descreve a organização social profissional dos pescadores amapaenses na foz do rio Amazonas. A área onde foi desenvolvido o estudo abrange a Mesorregião Norte e a Mesorregião Sul do estado do Amapá. Na Mesorregião Norte, situa-se a Microrregião do Amapá onde está localizado o município de Amapá e na Mesorregião Sul, situa-se a Microrregião de Macapá que compreendem os municípios de Macapá, Santana, Mazagão, Cutias do Araguari, Itaubal e Ferreira Gomes. Os dados foram coletados no período de agosto de 2016 a novembro de 2017 junto a pescadores artesanais do Amapá. Após identificação de todas as organizações que atuam no Amapá foram selecionadas as que representam os pescadores artesanais que tradicionalmente operam na foz do rio Amazonas. A principal forma de organização profissional é a colônia de pescadores. As organizações sociais profissionais dos pescadores no estado do Amapá estão representadas nos 16 municípios amapaenses por 18 colônias de pescadores artesanais e aquicultores, três associações de pescadores artesanais e cinco cooperativas, totalizando 26 organizações. O estudo ratifica a grande importância social da pesca artesanal na foz do rio Amazonas

Pescadores artesanais da foz do Rio Amazonas, Amazônia, Brasil

O trabalho descreve a socioeconomia e a percepção ambiental dos pescadores amapaense na foz do rio Amazonas. A área em que foi desenvolvido o estudo abrange a Mesorregião Norte, onde situa-se a Microrregião do Amapá, na qual localiza-se o município de Amapá e na Mesorregião Sul, onde situa-se a Microrregião de Macapá que compreendem os municípios de Macapá, Santana, Mazagão, Cutias do Araguari, Itaubal do Piririm e Ferreira Gomes. Os dados foram coletados junto a pescadores artesanais no período de agosto de 2016 a novembro de 2017. A maioria dos pescadores é amapaense (87,9%), 12,1% paraense/maranhense; as pescarias são praticadas por homens (77%) que vivem maritalmente (60%); a idade média é de 46 anos e possuem em média 4,61 filhos/família; o nível de escolaridade é baixo e observou-se que o interesse dos pescadores em aprenderem a assinar o nome ocorre devido a exigência dos órgãos para liberação de benefícios. A maioria dos pescadores utilizam a rede de emalhar como principal e mais importante arte de pesca na área da foz do Rio Amazonas (91,37%), seguida pela distribuição percentual em ordem decrescente de importância, pelo espinhel, linha de mão, tarrafa, zagaia e arpão. Os auxílios diversos complementares à renda familiar são majoritariamente provenientes do seguro defeso (91,9%) e também de bolsas do governo (30,6%). Nas pescarias são utilizados casquinhos (14%), canoas (25%), rabetas (32%) e geleiras (29%). O estudo ratifica a necessidade de medidas para a melhoria da qualidade de vida do pescador e a sustentabilidade da atividade pesqueira na região

"Mushroom cloud": a giant left ventricular pseudoaneurysm after a myocardial infarction due to myocardial bridging – a case report

Left ventricular pseudoaneurysm is an uncommon complication after transmural myocardial infarction, occurring when a free wall rupture is contained by adhesions of the overlying pericardium preventing acute tamponade. In this report, an unusual case of a 61 year-old male with a giant apical left ventricular pseudoaneurysm after an unnoticed myocardial infarction is presented. On coronary angiogram myocardial bridging of the distal left anterior descending artery was judged to be the infarct related lesion. The echocardiographic diagnosis allowed for a timely surgical intervention which resulted in the patient's full recovery

Efeito de diferentes concentrações de progesterona em dispositivos vaginais sobre a dinâmica folicular de novilhas Holandesas (Bos taurus) submetidas à IATF

Avaliou-se o efeito de diferentes concentrações de P4 [0,75g (T1) e 1g (T2)] sobre a dinâmica folicular de novilhas púberes submetidas à IATF. No D0 do protocolo, as fêmeas do T1 (n=10) e do T2 (n=9) receberam P4 em dispositivos intravaginais e, intramuscularmente, 2mg de BE. No D7 aplicou-se 530?g de cloprostenol e 300 UI de eCG, no D8 removeu-se os dispositivos, no D9 administrou-se 1 mg de BE e no D10 realizou-se a inseminação. A sincronização da onda folicular ocorreu em 100% das fêmeas. O diâmetro (mm) do folículo dominante (FD), avaliado no D9, o diâmetro máximo do FD o diâmetro máximo do folículo ovulatório (FO) não havendo diferença (P>0,05) entre os tratamentos. A média de crescimento diário dos folículos foi maior (P<0,05) no T1 (1,6±0,12) do que no T2 (1,0±0,18). O diâmetro do FD das novilhas do T1 e do T2 não diferiu (P<0,05), tanto das que ovularam quanto das que não ovularam. O diâmetro do FD entre as novilhas que ovularam com o daquelas que não ovularam foi maior (P<0,05) tanto no T1 (14,8±0,6 vs 9,6±0,7) quanto no T2 (11,2±1,6 vs 7,7±0,03). A porcentagem de prenhez não diferiu entre T1 e T2.  Os resultados indicam que ambas as dosagens de P4 são eficientes para induzir a emergência da nova onda folicular, controlar o crescimento folicular e sincronizar a ovulação de novilhas púberes