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BACKGROUND: The effects of current distribution and cell hydrodynamics on the performance of an electrocoagulation (EC) reactor were studied. This analysis only considered the distributions of primary potential and current density. The hydrodynamic behavior was analyzed by means of computational fluid dynamics (CFD) using a turbulent model (k-ε). For this study, only the fluid movement between electrodes was taken into account. RESULTS:The analysis of current distribution showed the effects of cell geometry and electrode configuration on both the potential and current distributions on the anodes. Insulators placed at the edges of the electrodes produced border effects on the potential values that favored a secondary reaction and diminished the formation of aluminum clots. The CFD analysis indicated that the cell geometry arrangement generates low velocity profiles between the electrodes. From the experimental evaluation, it was observed that EC performance was improved when uniform potential and current densities were achieved with low flow velocity profiles. CONCLUSIONS: Analysis of the hydrodynamic behavior showed the impact of different hydrodynamic phenomena on both the formation of clots and the removal of the sludge formed. Likewise, it was confirmed that in optimizing energy consumption, an analysis of current distribution is a very useful tool for evaluating the arrangement of electrodes and the cell geometry.

The objective of this study was to evaluate the effects of natural zeolite on the performance and nitrogen metabolism of Rambouillet ewe lambs. Forty Rambouillet ewe lambs with an initial weight of 41.06 ± 3.9 kg were randomly assigned to one of four experimental diets, namely 0, 20, 40 and 60 g of natural zeolite (Comercializadora Omega® México) per kg dietary dry matter in a completely randomized design and sixteen ewe lambs were used in a 4 x 4 Latin square metabolism study. Performance was not modified by natural zeolite levels in the diet, and daily gain showed a quadratic response. Ammonia concentration at 8 and 12 hours increased linearly with zeolite. Zeolite increased ruminal pH linearly at 8 and 12 hours. Acetate and butyrate presented a quadratic response, and total ruminal volatile fatty acid concentration was linearly increased by zeolite. Nitrogen retention showed a linear and quadratic response to zeolite. The estimated fractions of protein digested in the small intestine, when rumen-fermentable energy was limiting (PDIE) and when rumen-fermentable nitrogen was limiting, showed a linear and quadratic response to zeolite. PDIE was positively correlated (r = 0.96) with average daily gain.

To evaluate phenolic compounds and whether the combination of a tanniferous fruit and soybean oil could improve the performance, meat characteristics, and fatty acid (FA) profile in lambs, an experiment was conducted over 40 days with twenty creole male lambs (23.71 ± 3.46 kg). The lambs were allotted in a completely randomised design, with factorial arrangement 2 × 2, with the following dietary treatments: (1) control diet, (2) 2% Caesalpinia coriaria ground fruit dry matter (DM), (3) 2% soybean oil DM, and (4) 2% Caesalpinia coriaria fruit plus 2% soybean oil. The concentration of condensed tannins (CT) in Caesalpinia coriacea was 21.71 g/kg DM. No interactions were detected (P > 0.05) among soybean oil and Caesalpinia coriaria, and there were no differences in daily gain, intake, and feed conversion. Soybean oil reduced (P < 0.05) DM digestibility (68.05 versus 59.56%). In fat from the longissimus thoracis et lumborum (LTL) muscle, only linoleic acid presented differences (P < 0.05) between treatments. The combination of Caesalpinia coriacea fruit and soybean oil did not improve lamb performance at the included levels.