Biological nitrogen removal in aerobic granular sequencing batch reactors is sensitively affected by process conditions (e.g. dissolved oxygen (DO) concentration, nitrogen loading rate (NLR), influent C/N ratio, among others). The variation of one of these process conditions affects the others, because often they are tightly linked. These interrelationships are a drawback for the experimental assessment of the target domain of process conditions required to enhance N-removal. Here, we have developed a model to determine the guidelines to design an automatic control strategy with the final aim of enhancing biological N-removal in a granular sequencing batch reactor. The model was first calibrated with experimental data from a granular sequencing batch reactor treating

The papain-like protease (PLpro) from zoonotic coronaviruses (CoVs) has been identified as a target with an essential role in viral respiratory diseases caused by Severe Acute Respiratory Syndrome-associated coronaviruses (SARS-CoVs). The design of PLpro inhibitors has been proposed as an alternative to developing potential drugs against this disease. In this work, 67 naphthalene-derived compounds as noncovalent PLpro inhibitors were studied using molecular modeling methods. Structural characteristics of the bioactive conformations of these inhibitors and their interactions at the SARS-CoV-1 PLpro binding site were reported here in detail, taking into account the flexibility of the protein residues. Firstly, a molecular docking protocol was used to obtain the orientations of the inhibitors. After this, the orientations were compared, and the recurrent interactions between the PLpro residues and ligand chemical groups were described (with LigRMSD and interaction fingerprints methods). In addition, efforts were made to find correlations between docking energy values and experimentally determined binding affinities. For this, the PLpro was sampled by using Gaussian Accelerated Molecular Dynamics (GaMD), generating multiple conformations of the binding site. Diverse protein conformations were selected and a cross-docking experiment was performed, yielding models of the 67 naphthalene-derived compounds adopting different binding modes. Representative complexes for each ligand were selected to obtain the highest correlation between docking energies and activities. A good correlation (R2 = 0.948) was found when this flexible docking protocol was performed.

Este estudio consistió en la evaluación de la aplicabilidad de pectina deshidratada a base de parchita (Passiflora edulis) como inhibidor de incrustaciones minerales. La pectina fue obtenida mediante un proceso de hidrólisis ácida, precipitación de la sustancia pectínica y posterior deshidratación, para caracterizarla física y químicamente posteriormente. Se formuló un agua sintética en base a la norma NACE TM0374-2007, y fue caracterizada de forma física y química. Consecutivamente se formularon los inhibidores a concentraciones de 2%, 4% y 6% m/V, considerando también partículas de pectina mayores o iguales a 841 micrones y menores o iguales a 420 micrones. Por otra parte, se evaluó la eficiencia de la pectina como antiincrustante en diferentes muestras de agua sintética, regidos por la norma NACE TM 0374-2007, obteniéndose que el inhibidor más eficiente fue el de 6% m/V. Por último, se aplicó un procedimiento de comparación múltiple entre los inhibidores formulados y el HCl, resultando así medias que no presentaron diferencias estadísticamente significativas. En síntesis, la pectina deshidratada a base de parchita demostró ser eficiente en el proceso de inhibición de la precipitación de incrustaciones minerales de Sulfato de Calcio (CaSO4), mejorando esto en base a una mayor concentración y un menor tamaño de partículas.

The present investigation was based on the experimental evaluation of the orange-based pectin (Citrus sinensis) as a viscosifier agent in polymeric drilling fluids. To develop the additive, the orange fruit peels were subjected to hydrolysis with citric acid, and then this solution was precipitated with ethanol and the resulting hydrogel was chemically and physically characterized. In the subsequent stage, fluid samples were formulated with xanthan gum and pectin to compare their performance through experimental laboratory procedures governed by API 13-B1. Finally, an Analysis of Variance was applied to determine the means that are significantly different from each other between the commercial product and the one proposed, through the Statgraphics program. In conclusion, it was obtained that pectin showed a statistically similar behavior, although inferior to xanthan gum as a viscosifier additive in polymeric drilling fluids, considering as a variant the expansion of its concentration for fluid rheology optimal development.

The main objective of this research was to develop a liquid foaming agent for optimizing gas production in wells belonging to the Santa Rosa field in Área Mayor de Anaco, Venezuela. In this research, three liquid foaming agent formulations were developed with an anionic and amphoteric surfactants mixture, performing tests to evaluate foaming and lifetime on samples with different produced water/hydrocarbon condensate ratios. A liquid drag test was also carried out, explaining the liquid recovery performance after applying the developed formulations at different dosages and finally evaluated products results were compared with a commercial one. Formulation 1 obtained a higher liquid recovery compared to the other formulations, in addition, recovered liquid amount in dynamic drag tests decreased as the condensates composition increased in four samples evaluated. Formulation 1 and commercial product used as a reference did not have statistically significant differences.