Función de calefacción en pastas de cemento con adición de nanofibras de carbono

The viability of carbon nanofiber (CNF) composites in cement matrices as a self-heating material is reported in this paper. This functional application would allow the use of CNF cement composites as a heating element in buildings, or for deicing pavements of civil engineering transport infrastructures, such as highways or airport runways. Cement pastes with the addition of different CNF dosages (from 0 to 5% by cement mass) have been prepared. Afterwards, tests were run at different fixed voltages (50, 100 and 150V), and the temperature of the specimens was registered. Also the possibility of using a casting method like shotcrete, instead of just pouring the fresh mix into the mild (with no system’s efficiency loss expected) was studied. Temperatures up to 138 °C were registered during shotcrete-5% CNF cement paste tests (showing initial 10 °C/min heating rates). However a minimum voltage was required in order to achieve a proper system functioning.En este artículo se estudia la viabilidad del uso de matrices cementicias con adición de nanofibras de carbono (NFC) como elementos calefactores. Esto permitiría aumentar la temperatura de estancias en edificación o el deshielo de pavimentos en obras civiles. Se han fabricado pastas de cemento con distintas dosificaciones de NFC (0, 1, 2 y 5% respecto masa del cemento) y sometidas al paso de corriente continua a distintos potenciales fijos (50, 100 y 150 V), mientras se controlaba la temperatura en distintos puntos. Se ha estudiado la viabilidad de utilizar la proyección de la pasta fresca como método de puesta en obra, sin perjudicar la eficiencia del sistema. Se consiguieron temperaturas de hasta 138 °C (con velocidades iniciales de 10 °C/min) para pasta proyectada con 5% NFC. Además se ha detectado la necesidad de un potencial mínimo para que la densidad de corriente resultante sea suficiente para producir el efecto esperado.The authors would like to thank the Spanish Ministerio de Ciencia e Innovación for its financial support (ref: Mat2009-10866)

Intercultural mediation at the end of life. Different perceptions of the same process

The aim of this study was to identify the perceptions of palliative care professionals with regards to the management of patients from a different culture, and if there is a need to incorporate an intercultural mediator. To understand the influence of the intercultural mediator as a facilitator in the decision making of the patient and family at the end of life. The methodological approach is centered in pluralism, reinforced by triangulation of data and information. The intercultural mediator is crucial because they can provide light in a multitude of conflict situations caused by lack of knowledge about the patient's culture. (C) 2017 The Authors. Published by Elsevier Ltd

Valuation of sewage sludge ash as a component of precast concrete

Se plantea la combinación binaria y ternaria de cenizas de lodo de depuradora (CLD) con ceniza volante, polvo de mármol y ceniza de cáscara de arroz, como sustitución parcial o como adición respecto al cemento Portland en hormigones, con una dosificación similar a la utilizada en la prefabricación de bloques (consistencia muy seca). Se llevaron a cabo ensayos físico-mecánicos sobre probetas de mortero y hormigón con edades de curado de 28 y 90 días: densidad, absorción y resistencia a compresión. Se comprueba que la sustitución de cemento por CLD supone una disminución de la densidad y de la resistencia respecto a la muestra patrón, sin embargo, las combinaciones con otros residuos mejoran notablemente las características de los materiales cementantes. La adición de CLD proporcionó densidades y resistencias similares a la muestra de control y reduce significativamente la absorción de agua.This paper proposes binary and ternary combinations of sewage sludge ash (SSA) with fly ash, marble dust and rice hull ash, as partial replacement or addition relative to Portland cement in concretes with a similar dosage to that used in the manufacture of precast blocks, with very dry consistency given its manufacturing process in plant. Several physical-mechanical tests were carried out on concrete and mortar specimens with curing ages of 28 and 90 days: density, water absorption and compressive strength. It is proved that replacing cement by SSA involves a decrease in density and compressive strength compared to the reference sample, however, the combinations of residues significantly improve the characteristics of the cementitious materials. The addition of SSA provided densities and resistances similar to the control sample and significantly reduces the water absorption

Anthropological and transcultural nursing in the context of education for development: a historical and epistemologic perspective in the principle of the XXI century

El objetivo de este trabajo consiste en clarificar históricamente el concepto de "desarrollo" y vincularlo a otro concepto, el de "educación"con la finalidad de aportar un marco idóneo para la acción educativa en enfermería, especialmente en enfermería antropológica y transcultural. Para ello se han identificado los significados de los conceptos implicados separada y conjuntamente procurando interrelacionar los factores sociales, ideológicos, económicos, políticos, científicos y metodológicos. Asimismo, una vez analizados y contextualizados los diferentes conceptos, atendiendo a su naturaleza, se ha procedido a seleccionar las técnicas y métodos idóneos para el trabajo en educación para el desarrollo y enfermería transcultural. Entre las conclusiones cabe destacar la importancia de la contextualización de todas las actividades de educación para el desarrollo, la necesidad de adoptar métodos y técnicas adecuados al contexto de la acción educativa en enfermería. Por otro lado se ha constatado que tanto la enfermería como la educación para el desarrollo comparten el carácter holístico con el que abordan su objeto-sujeto: el hombre en el proceso de satisfacción de necesidades. Los métodos y técnicas de investigación acción resultan ser los más adecuados para este tipo de trabajos debido, sobre todo a la repercusión de la actividad investigadora en la realidad investigada (no se agota el proceso científico en la producción de conocimientos). Tanto la enfermería para el desarrollo, como la enfermería comunitaria y la enfermería transcultural comparte el principio esencial y característico de tales disciplinas: el fomento de la participación en un clima de tolerancia y solidaridad. No es posible desarrollar ninguna actividad de educación para el desarrollo, enfermería comunitaria o enfermería transcultural sin la implicación previa de los individuos, las familias o las comunidades a las que vayan dirigidas.This work has the objective of clarify the development concept historically and relative it with another concept: education; and everything this process with the purpose of contributing to selection of a suitable context for educational nursing action, specially in anthropological and transcultural nursing

Highly Conductive Carbon Fiber Reinforced Concrete for Icing Prevention and Curing

This paper aims to study the feasibility of highly conductive carbon fiber reinforced concrete (CFRC) as a self-heating material for ice formation prevention and curing in pavements. Tests were carried out in lab ambient conditions at different fixed voltages and then introduced in a freezer at −15 °C. The specimens inside the freezer were exposed to different fixed voltages when reaching +5 °C for prevention of icing and when reaching the temperature inside the freezer, i.e., −15 °C, for curing of icing. Results show that this concrete could act as a heating element in pavements with risk of ice formation, consuming a reasonable amount of energy for both anti-icing (prevention) and deicing (curing), which could turn into an environmentally friendly and cost-effective deicing method.Authors want to acknowledge Generalitat Valenciana (PROMETEO/2013/035) for their economic support on this research, including funds for covering the costs to publish in open access

Concrete for precast blocks: binary and ternary combination of sewage sludge ash with diverse mineral residue

[EN] This paper proposes binary and ternary combinations of sewage sludge ash (SSA) with fly ash (FA), marble dust (MD) and rice husk ash (RHA) as partial replacements of Portland cement in concretes with a similar dosage to that used in precast blocks, with very dry consistency. Several physical-mechanical tests were carried out on concrete specimens with curing ages of 28 and 90 days: density, water absorption, capillary water absorption, ultrasonic pulse velocity and compressive strength. The combinations of residues significantly improve the properties of the cementitious systems: 30% replacement of Portland cement provides strength values similar to the reference sample, showing the synergetic effects of the combination of the mineral additions. The significance of this research relies on the combined use of the mineral additions as well as the use of them for the precast block industry. The results show synergies among the additions and even that some of them showed relevant improvements when they are used in combination, performing better than when used individually.Baeza-Brotons, F.; Paya Bernabeu, JJ.; Galao, O.; Alberti, MG.; Garcés, P. (2020). Concrete for precast blocks: binary and ternary combination of sewage sludge ash with diverse mineral residue. Materials. 13(20):1-19. https://doi.org/10.3390/ma13204634S1191320Zabalza Bribián, I., Valero Capilla, A., & Aranda Usón, A. (2011). Life cycle assessment of building materials: Comparative analysis of energy and environmental impacts and evaluation of the eco-efficiency improvement potential. Building and Environment, 46(5), 1133-1140. doi:10.1016/j.buildenv.2010.12.002Lothenbach, B., Scrivener, K., & Hooton, R. D. (2011). Supplementary cementitious materials. Cement and Concrete Research, 41(12), 1244-1256. doi:10.1016/j.cemconres.2010.12.001Ministerio de Agricultura Alimentación y Medio Ambiente http://www.magrama.gob.es/es/calidad-y-evaluacion-ambiental/temas/prevencion-y-gestion-residuos/flujos/lodos-depCyr, M., Coutand, M., & Clastres, P. (2007). Technological and environmental behavior of sewage sludge ash (SSA) in cement-based materials. Cement and Concrete Research, 37(8), 1278-1289. doi:10.1016/j.cemconres.2007.04.003Donatello, S., & Cheeseman, C. R. (2013). Recycling and recovery routes for incinerated sewage sludge ash (ISSA): A review. Waste Management, 33(11), 2328-2340. doi:10.1016/j.wasman.2013.05.024Marble Association of Alicante http://www.marmoldealicante.esChen, M., Blanc, D., Gautier, M., Mehu, J., & Gourdon, R. (2013). Environmental and technical assessments of the potential utilization of sewage sludge ashes (SSAs) as secondary raw materials in construction. 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Cement and Concrete Composites, 32(2), 121-127. doi:10.1016/j.cemconcomp.2009.10.008Research Group in Chemistry Building Materials—Universitat Politècnica de València. Proyecto PEL-CEN http://epsar.cop.gva.es/depuradorasvPeris Mora, E., Payá, J., & Monzó, J. (1993). Influence of different sized fractions of a fly ash on workability of mortars. Cement and Concrete Research, 23(4), 917-924. doi:10.1016/0008-8846(93)90045-bEvolución de las resistencias mecánicas de sistemas ternarios cemento/ceniza volante/ceniza de lodo de depuradora: Efectos puzolánicos complementarios https://www.upv.es/pms2002/Comunicaciones/038 PAYA.PDFCorinaldesi, V., Moriconi, G., & Naik, T. R. (2010). Characterization of marble powder for its use in mortar and concrete. 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Mechanical properties and durability assessment of rice husk ash concrete. Biosystems Engineering, 110(2), 144-152. doi:10.1016/j.biosystemseng.2011.07.009Nicoara, A. I., Stoica, A. E., Vrabec, M., Šmuc Rogan, N., Sturm, S., Ow-Yang, C., … Vasile, B. S. (2020). End-of-Life Materials Used as Supplementary Cementitious Materials in the Concrete Industry. Materials, 13(8), 1954. doi:10.3390/ma13081954García Arenas, C., Marrero, M., Leiva, C., Solís-Guzmán, J., & Vilches Arenas, L. F. (2011). High fire resistance in blocks containing coal combustion fly ashes and bottom ash. Waste Management, 31(8), 1783-1789. doi:10.1016/j.wasman.2011.03.017Poon, C.-S., Kou, S., Wan, H., & Etxeberria, M. (2009). Properties of concrete blocks prepared with low grade recycled aggregates. Waste Management, 29(8), 2369-2377. doi:10.1016/j.wasman.2009.02.018Sabai, M. M., Cox, M. G. D. M., Mato, R. R., Egmond, E. L. C., & Lichtenberg, J. J. N. (2013). 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Saccharomyces cerevisiae: a versatile eukaryotic system in virology

The yeast Saccharomyces cerevisiae is a well-established model system for understanding fundamental cellular processes relevant to higher eukaryotic organisms. Less known is its value for virus research, an area in which Saccharomyces cerevisiae has proven to be very fruitful as well. The present review will discuss the main achievements of yeast-based studies in basic and applied virus research. These include the analysis of the function of individual proteins from important pathogenic viruses, the elucidation of key processes in viral replication through the development of systems that allow the replication of higher eukayotic viruses in yeast, and the use of yeast in antiviral drug development and vaccine production

Mechanical Properties and Durability of CNT Cement Composites

In the present paper, changes in mechanical properties of Portland cement-based mortars due to the addition of carbon nanotubes (CNT) and corrosion of embedded steel rebars in CNT cement pastes are reported. Bending strength, compression strength, porosity and density of mortars were determined and related to the CNT dosages. CNT cement paste specimens were exposed to carbonation and chloride attacks, and results on steel corrosion rate tests were related to CNT dosages. The increase in CNT content implies no significant variations of mechanical properties but higher steel corrosion intensities were observed.The authors would like to acknowledge the Spanish Ministry of Science and Innovation (Ref: Mat 2009-10866) and Generalitat Valenciana (PROMETEO/2013/035) for their economic support on this research

Hormigón conductor reforzado con fibras de carbono para la prevención y remediación de heladas en pavimentos de carreteras y aeropuertos

Póster presentado en el I Congreso Nacional PRE-CONPAT 16, Madrid, 2 de diciembre de 2016.La función de calefacción que poseen los materiales cementantes conductores presenta un importante campo de aplicación en las infraestructuras de transporte. La adición de fibras de carbono (FC) en bajas cantidades al hormigón mejora sustancialmente su conductividad eléctrica, lo que puede ser aprovechado para acometer actuaciones de prevención y curación de heladas en pavimentos de carreteras y aeropuertos, frente a otros métodos más agresivos o de mayor coste económico.Los autores agradecen a la Consellería de Educación, Formación y Empleo de la Generalitat Valenciana, la financiación de la investigación realizada en el marco del proyecto “Prometeo 2013/035. Materiales cementantes conductores multifuncionales inteligentes”