Optimization of oxygen transfer through venturi-based systems applied to the biological sweetening of biogas

Peer ReviewedPostprint (published version

Actividades relacionadas con la implementación de laestrategia de comunicación desarrollada por elProyecto Páramo Andino en el Páramo de Santa Inés(Belmira)

Informe final del trabajo realizado en los municipios de influencia del sistema de Páramos y Bosques Altoandinos del Noroccidente medio Antioqueño y otras zonas del departamento que se benefician de sus servicios ambientales, continuando con la estrategia de comunicación participativa formulada para promover el reconocimiento, la protección y la divulgación de sus ventajas y su situación ambiental.Medelli

La experiencia de estudiantes de enfermería ante el dolor infligido en la práctica clínica

Objetivo: Describir el significado de la experiencia de infligir dolor de los enfermeros en formación matriculados en el Programa de Enfermería de la Facultad de Ciencias de la Salud de la Universidad del Tolima. Materiales y métodos: Se realizó una investigación con enfoque fenomenológico, durante el semestre académico A 2012 (comprendido entre los meses de enero a junio). En la muestra participaron de forma voluntaria, luego de conocer la naturaleza y propósitos del estudio 14 estudiantes, cuyas edades oscilaron entre 17 y 23 años. Se les aplico una entrevista en profundidad de forma individual. Resultados: La experiencia expresada por los estudiantes permitió identificar dos categorías; las vivencias y las estrategias de afrontamiento ante la situación. Conclusión: La experiencia de causar dolor vivida por el enfermero novicio difiere de la del enfermero experto según el estudio realizado por Madjar. La investigación demostró la necesidad de incluir en el currículo del Programa de Enfermería, actividades que fomenten el desarrollo de estrategias de afrontamiento, a partir de la aplicación de metodologías que le permitan al docente identificar las respuestas humanas del estudiante ante situaciones de estrés. Así como el estudiante interpreta los códigos de comunicación no verbal del otro: el sujeto de cuidado también descubre en su cuidador ese cúmulo de emociones, sentimientos, temores y hasta logra interpretar en algunos casos el nivel de conocimiento que aflora durante su encuentro

Evaluation of mass transfer coefficients in biotrickling filters: experimental determination and comparison to correlations

This is the pre-peer reviewed version of the following article: Dorado, A.D. [et al.]. Evaluation of mass transfer coefficients in biotrickling filters: experimental determination and comparison to correlations. "Chemical engineering and technology", Setembre 2009, vol. 32, núm. 12, p. 1941-1950, which has been published in final form at https://doi.org/10.1002/ceat.200900275. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.Overall mass transfer coefficients (KGa and KLa) were determined experimentally for four different-nature packing materials used in gas-phase biotrickling filters. A simple methodology based on overall mass balances and following a standard procedure allowed to calculate the mass transfer coefficients under different operating conditions corresponding to usual biotrickling filtration situations. Results showed an increase of mass transfer resistance when increasing the empty bed residence time (EBRT) of the reactor for all packing materials. Experimental results were fitted to existing and well-accepted correlations used in conventional biofilter or biotrickling filter modeling. The comparison of experimental and theoretical data showed huge discrepancies. Simple correlations for the experimental data obtained in this study were also suggested.Peer ReviewedPostprint (author's final draft

Efectos de la variación del precio del dólar en el sector de la construcción en Medellín, 2012 - 2016. (Effects of the variation of the Dollar Price in the Construction Sector in Medellín, 2012 - 2016).

El sector de la construcción tiene grandes beneficios para lasociedad a nivel social y económico. Las variaciones del precio del dólar americano generan efectos sobre la economía colombiana pero aún no se visualizan análisis sobre posibles efectos de éstas sobre el sector de la construcción. Este trabajo tiene como objetivo principal identificar efectos que ha generado el incremento del precio del dólar sobre el sector de la construcción en la ciudad de Medellín en los últimos cinco años. Se utiliza un análisis basado en revisión documental, también en el método Delphi y un modelo de regresión simple, con el fin mostrar evidencias y de visualizar los problemas desde un punto de vista amplio. Los resultados permiten visualizar que el precio del dólar, en efecto, ha generado algunos cambios en el sector de la construcción colombiana, como aumento en costos, problemas de rentabilidad, de inversión, entre otros aspectos

Biotrickling filters for biogas sweetening: oxygen transfer improvement for a reliable operation

An industrial-scale biotrickling filter for the removal of high concentrations of H2S is described in this work. The system has been operating at H2S inlet concentrations between 1000 and 3000 ppmv at acidic conditions. A decrease of pH from 2.6 to 1.8 did not affect the biological activity inside the biofilter while reducing the water make-up consumption up to 75%. The current oxygen supply system, based on direct injection of air to the liquid phase, has demonstrated to be inefficient for a long-term operation leading to elemental sulfur accumulation in the packing material (i.e. promoting clogging episodes). The present study demonstrates it is possible to partially remove (40.3%) the deposited elemental sulfur by bio-oxidation when biogas is not fed. In normal operation conditions, the implementation of an aeration system based on jet-venturi devices has shown quite promising results in terms of oxygen transfer efficiency and robustness. Such improvement of oxygen transfer was translated in a better conversion of H2S to sulfate, which increased around 17%, prolonging the lifespan operation at low-pressure drop.Peer ReviewedPreprin

Closed-loop compensation of dielectric charge induced by ionizing radiation

This letter investigates the capability of dielectric charge control loops to cope with charge induced by ionizing radiation. To this effect, an microelectromechanical systems (MEMS) variable capacitor has been irradiated with X-rays and gamma-radiation in three scenarios: 1) without polarization; 2) using an open-loop dielectric charge mitigation strategy; and 3) using a closed-loop control method. The results show that the charge effects induced by radiation can be partially compensated using dielectric charge control.Peer ReviewedPostprint (author's final draft

Influence of 1D and 2D carbon fillers and their functionalisation on crystallisation and thermomechanical properties of injection moulded nylon 6,6 nanocomposites

Carbon nanotubes (CNTs) and graphene were used as reinforcing fillers in nylon 6,6 in order to obtain nanocomposites by using an injection moulding process. The two differently structured nanofillers were used in their pristine or reduced form, after oxidation treatment and after amino functionalisation.Three low nanofiller contents were employed. Crystallisation behaviour and perfection of nylon 6,6 crystals were determined by differential scanning calorimetry and wide angle X-ray diffraction, respectively. Crystallinity was slightly enhanced in most samples as the content of the nanofillers was increased. The dimensionality of the materials was found to provide different interfaces and therefore different features in the nylon 6,6 crystal growth resulting in improved crystal perfection. Dynamical, mechanical analysis showed the maximum increases provided by the two nanostructures correspond to the addition of 0.1 wt.% amino functionalised CNTs, enhancing in 30% the storage modulus and the incorporation of 0.5 wt.% of graphene oxide caused an increase of 44% in this property. The latter also provided better thermal stability when compared to pure nylon 6,6 under inert conditions. The superior properties of graphene nanocomposites were attributed to the larger surface area of the two-dimensional graphene compared to the one-dimensional CNTs

Generation of a bank of clinical-grade, HLA-homozygous iPSC lines with high coverage of the Spanish population

BackgroundInduced pluripotent stem cell (iPSC)-derived cell therapies are an interesting new area in the field of regenerative medicine. One of the approaches to decrease the costs of iPSC-derived therapies is the use of allogenic homozygous human leukocyte antigen (HLA)-matched donors to generate iPSC lines and to build a clinical-grade iPSC bank covering a high percentage of the Spanish population.MethodsThe Spanish Stem Cell Transplantation Registry was screened for cord blood units (CBUs) homozygous for the most common HLA-A, HLA-B and HLA-DRB1 haplotypes. Seven donors were selected with haplotypes covering 21.37% of the haplotypes of the Spanish population. CD34-positive hematopoietic progenitors were isolated from the mononuclear cell fraction of frozen cord blood units from each donor by density gradient centrifugation and further by immune magnetic labeling and separation using purification columns. Purified CD34 + cells were reprogrammed to iPSCs by transduction with the CTS CytoTune-iPS 2.1 Sendai Reprogramming Kit.ResultsThe iPSCs generated from the 7 donors were expanded, characterized, banked and registered. Master cell banks (MCBs) and working cell banks (WCBs) from the iPSCs of each donor were produced under GMP conditions in qualified clean rooms.ConclusionsHere, we present the first clinical-grade, iPSC haplobank in Spain made from CD34 + cells from seven cord blood units homozygous for the most common HLA-A, HLA-B and HLA-DRB1 haplotypes within the Spanish population. We describe their generation by transduction with Sendai viral vectors and their GMP-compliant expansion and banking. These haplolines will constitute starting materials for advanced therapy medicinal product development (ATMP)