High-whiteness kaolinite mining reserves are scarce. In some locations, it is necessary to remove material to access them (adding to the cost). Therefore, processes have been developed to eliminate contaminants, such as iron, and provide alternatives to the used contaminated materials that, after being treated, meet quality criteria. In our previous research, we developed an electrochemical process for kaolin whitening at the laboratory level and bench scale, demonstrating the reaction mechanisms that occur during the removal of iron from kaolin. However, the geometry used at the laboratory level does not present the most suitable position for the electrodes. Therefore, in the present study, we focused on the geometry and the function of the electrodes. This is necessary during the escalation process to reach the pilot-scale level. The study was carried out using computer-aided engineering in the COMSOL Multiphysics computer program and by analysing the distribution of the electric potential and the electric current of the geometries considered while performing the scaling. The results indicated that the change in the anode position from perpendicular to parallel to the discs improved the distribution of electric current density on the cathode surface and so increased the elimination of iron through electrochemical deposition. Similarly, to reduce the amount of material used in the construction of the reactor, the anode-size effect was analysed, revealing that relatively small anodes improved the distribution of electric current density over the entire surface of the electrode and not only at the edges.

We introduce the polygon cloud, a compressible representation of three-dimensional geometry (including attributes, such as color), intermediate between polygonal meshes and point clouds. Dynamic polygon clouds, like dynamic polygonal meshes and dynamic point clouds, can take advantage of temporal redundancy for compression. In this paper, we propose methods for compressing both static and dynamic polygon clouds, specifically triangle clouds. We compare triangle clouds to both triangle meshes and point clouds in terms of compression, for live captured dynamic colored geometry. We find that triangle clouds can be compressed nearly as well as triangle meshes, while being more robust to noise and other structures typically found in live captures, which violate the assumption of a smooth surface manifold, such as lines, points, and ragged boundaries. We also find that triangle clouds can be used to compress point clouds with significantly better performance than previously demonstrated point cloud compression methods. For intra-frame coding of geometry, our method improves upon octree-based intra-frame coding by a factor of 5–10 in bit rate. Inter-frame coding improves this by another factor of 2–5. Overall, our proposed method improves over the previous state-of-the-art in dynamic point cloud compression by 33% or more.

We assessed the importance of potential sources of mortality for the Vulnerable southern pudu Pudu puda in southern Chile using the clinical records of wildlife rehabilitation centres, necropsies of animals found in the field and a review of the diet of potential predators. To assess whether the identified mortality sources operate in nominally protected areas, we conducted a camera-trap survey in two areas to determine the presence of pudus and their potential predators. Predation by domestic dogs Canis lupus familiaris and car collisions were the commonest causes of pudu admissions to rehabilitation centres (35 of 44) and of deaths of animals encountered opportunistically in the field (seven of 14). Field data suggest that poaching could also be an important threat to pudus. Pudus were detected in both areas surveyed, accounting for 15.6% of mammal detections. Dogs accounted for 47.8% of all detections of potential predator species, followed by pumas Puma concolor (17.4%), guignas Leopardus guigna (17.4%) and chilla foxes Lycalopex griseus (17.4%). The literature survey implicated only pumas as important pudu predators among native carnivores. Our data suggest that, aside from forest loss, dogs, road kills and probably poaching are important concerns for pudu conservation. Our frequent detections of free-ranging dogs associated with roads within nominally protected areas suggest that long-term efforts to conserve pudu will require not only the protection of remnant native forest but also substantive environmental education to modify dog management near protected areas.