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- PublicaciónAcceso abiertoA database of common vampire bat reports(2022-02-16)The common vampire bat (Desmodus rotundus) is a sanguivorous (i.e., blood-eating) bat species distributed in the Americas from northern Mexico southwards to central Chile and Argentina. Desmodus rotundus is one of only three mammal species known to feed exclusively on blood, mainly from domestic mammals, although large wildlife and occasionally humans can also serve as a food source. Blood feeding makes D. rotundus an effective transmissor of pathogens to its prey. Consequently, this species is a common target of culling efforts by various individuals and organizations. Nevertheless, little is known about the historical distribution of D. rotundus. Detailed occurrence data are critical for the accurate assessment of past and current distributions of D. rotundus as part of ecological, biogeographical, and epidemiological research. This article presents a dataset of D. rotundus historical occurrence reports, including >39,000 locality reports across the Americas to facilitate the development of spatiotemporal studies of the species. Data are available at https://doi.org/10.6084/m9.figshare.15025296
- PublicaciónAcceso abiertoDetermination of the gelification kinetics of a correction gel of injection profiles by ultraviolet-visible spectroscopy(2020-08-05)Mature wells in which, for a long time, water injection has been used, as a method of recovery they reach a point where the water cut increases or remains constant. thus decreasing the recovered hydrocarbon factor; This phenomenon occurs because the water injected, has preferential recordings in the porous medium, and does not reach the hydrocarbon available in other areas of the formation, in this type of deposits the injection of polyacrylamide gels, crosslinked with acetate of chromium, these gels make a plugging, in areas of high water permeability, causing the change of path of the same, as well as move the hydrocarbon in other areas of the porous medium. At present, the kinetics of gelation of this type of substances is monitored qualitatively by means of the "Syddansk" code, which analyzes its consistency and elasticity, only by observation. Although this method is practical, it is not very descriptive and depends a lot on the opinion and criteria of the observer, being little reproducible. Given this situation, and the increase in chemical recovery projects in the country, a methodology is described that describes the moment of gelation, reproducibly and without the injection of the analyst. During the gelation process, different polyacrylamide-chromium gels were monitored in relationships used in field operations, using ultraviolet-visible spectroscopy, detecting a change in absorbances, of the spectra, which were analyzed to plant a kinetic model of gelation, in addition to generating the approach of a method, to identify the state of gelation based on the variation in absorbance.
- PublicaciónAcceso abiertoComparative analysis between asphaltites and extra heavy oil asphaltenes(2020-12-05)The asphaltite material receives many names depending on the country, or area of knowledge, for this reason it is also known as bitumen, asphalt and gilsonite, its composition is a mixture of high molecular weight organic substances, mainly polyaromatic compounds characterized by a black color, and they appear in a semi-solid or solid state. Asphaltenes correspond to the oil fraction with the highest molecular weight, this characteristic provides a high viscosity to hydrocarbons, which contain, in their composition, a concentration equal to or greater than 10%, although the exact structure of this is not known. molecular family, it has been possible to elucidate the functional groups present, such as carbonyl acids, thiols and pyridines, implying the presence of heteroatoms, such as nitrogen, sulfur and oxygen, but the most characteristic part of this type of molecules is their nucleus polyaromatic, which can contain up to 20 or more benzene rings. A sample of Colombian asphaltite was taken and compared with a sample of asphaltenes from a Colombian extra-heavy crude, solubility tests, a spectroscopic characterization by Ultraviolet-Visible, infrared, a thermal evaluation by Thermogravimetry and Differential Scanning Calorimetry were carried out. , in addition to an analysis by X-ray diffraction, in order to determine if the behavior and composition of both The objective of this investigation is to be analyzed by comparing a traditional asphaltite and an asphaltite, if the latter has the same properties and composition, with a view to being used as an energy source .The results obtained reveal that despite the fact that both substances present a similar composition, their glass transitions are different, as well as the crystalline phases present in each of the materials.
- PublicaciónAcceso abiertoPost-consumption foamed polystyrene coatings for surface tension modification(2020-08-05)Foamed polystyrene, commercially known as Icopor, occupies a very important place in the transport systems, and conservation of freight and food, but it is also one of the main polymeric pollutants, due to its low biodegradability, and low reuse. Polystyrene has in its structure aromatic and aliphatic functional groups, which have a high hydrophobicity, which makes them candidates as modifiers of permeability and surface properties, although for this purpose the implementation of solvents is also required. In the following work, polystyrene residues for domestic and food use were used to obtain coatings, which allow surface tension to be modified, on surfaces with high water permeability. For this purpose, the polymeric residue was dissolved in organic type solvents, generating a varnish, which was used to coat the study surface, from which the surface tension with respect to water was previously known by analysing the contact angle; to be compared with those obtained after coating, resulting in an increase in the contact angle, which indicates an increase in surface tension, conferred on the new surface hydrophobicity.
- PublicaciónAcceso abiertoGeological and physical-chemistry characterization of asphaltite from Colombian Middle Magdalena region(2020-08-05)The massive consumption of fossil hydrocarbons and the absence of new conventional oil reserves, research on unconventional resources is prevalent. The Asphaltite is a substance with high energy value thanks to its composition of high molecular weight hydrocarbons, becomes an energy alternative in the future. In Middle Magdalena region of Colombia, Luna formation emerges with its members Salada, Pujamana, and Galembo of Upper Cretaceous age, which contains a deposit of this type of substances, which can become an economic and energy engine for the region. A representative sample of this asphaltite was taken in the Galembo Member (Top of Luna formation) and a geological description was made about its formation and occurrence in the area. The solubility of asphaltite was evaluated in two characteristic solvents for hydrocarbons, toluene and heptane, the first of aromatic character, with which it was possible to solubilize probably corresponding to the light fractions, while solubilization with heptane generated a precipitate Asphaltene, a nature that was corroborated by tests of visible infrared and ultraviolet spectroscopy, additionally an elementary analysis was performed to determine the concentrations of carbon, hydrogen, sulphur and oxygen. Finally, by means of thermogravimetry and differential scanning calorimetry an analysis was carried out to evaluate its energy potential, according to the results obtained, asphaltite samples are a promising energy resource.