La lógica proposicional y su aplicación en contexto

Los alumnos, cuando abordan en sus cursos de matemáticas el tema de la lógica proposicional, manifiestan un alto grado de desmotivación, debido a la manera como este se les presenta. Su enseñanza se centra en encontrar el valor de verdad de las proposiciones y demostrar sus propiedades mediante el uso de tablas de verdad, olvidando, en la mayoría de los casos, la importancia de aplicar dichos conceptos y propiedades a situaciones reales, lo que daría sentido a lo que aprenden, pues además de desarrollarles el pensamiento formal, les permitiría adquirir un aprendizaje significativo. De esta manera, lo que se pretende con este trabajo es presentar algunos ejemplos en contextos reales, donde se apliquen ciertos conceptos y propiedades de la lógica proposicional, que sirvan como motivación para el trabajo en el aula tanto para docentes como para estudiantes, como una manera de ayudar a estos últimos a desarrollar el pensamiento formal y a adquirir un aprendizaje significativo de esta área del saber. Se presentan los distintos conectivos lógicos (negación, conjunción, disyunción, condicional y bicondicional), se muestran algunos referentes teóricos y se dan algunos ejemplos en contexto

La utilización de videos y preguntas como estrategia para la enseñanza del cálculo

Los videos se han consolidado como un recurso de gran acogida entre los estudiantes para su trabajo independiente en los cursos de Matemáticas y Cálculo en los primeros semestres de educación superior. Como precedente puede mencionarse el caso de Khan Academy. Por otro lado, los Objetos Interactivos de Aprendizaje (OIA) también son un recurso que no debe ignorarse en la búsqueda de una mejor enseñanza por el docente y un mejor aprendizaje para el estudiante. Ahora se propone utilizar estos dos recursos en forma simultánea como un complemento el uno del otro buscando aprovechar las ventajas de ambos. Esta convergencia de ambos recursos es una propuesta que busca prevenir que el contenido ininterrumpido en el video llegue a ser tedioso para el estudiante. A la vez, busca que se aprovechen las pausas con preguntas oportunas para lograr que el estudiante vaya retroalimentando durante la reproducción misma del video y no solo al final, que es lo común

Diseño de un modelo de mejoramiento del servicio en los equipos de recarga de extintores para aumentar el indicador de satisfacción de servicio al cliente en el segmento b2b aplicando a la Empresa Scimitar

Las organizaciones pueden optar, por la vanguardia mediante el desarrollo de mejoras constantes en la gestión de servicio al cliente, desde el manejo eficaz y eficiente de la información relevante para ofrecer un buen servicio hasta la implementación de nuevas tecnologías y activos en término de proporcionar el debido soporte que posibilite superar tiempos de respuesta y mejorar los resultados económicos y financieros. SCIMITAR es una empresa familiar que inició sus actividades empresariales en 1985 y su mercadeo se localizó en el Distrito Metropolitano de Quito. Su giro del negocio se orienta a la comercialización y servicio de recarga de extintores, venta de señalizaciones informativas, sistemas de extinción y detección de incendios e implementos de seguridad industrial. Durante los últimos años los dueños y altos mandos han querido perfeccionar la actividad comercial mediante la implementación de un sistema que permita mejorar los tiempos de respuesta y así ofrecer un mejor servicio al cliente. El presente estudio se direccionó a proponer una metodología que ayude a llevar de mejor manera los datos de clientes sobre registros de recargas o ventas; mejorar la atención y llegar de una manera adecuada mediante redes sociales email, pagina web, o de forma directa, además distinguir y categorizar a los clientes por sus compras. Se ha realizado una investigación descriptiva para el levantamiento de datos. Al finalizar la investigación, se valoró que la empresa mediante esta implementación mejorará el servicio en varios aspectos como: manejo de información, tiempos de respuesta, atención al cliente e ingresos mayore

Understanding Interactions between Design Team Members of Construction Projects Using Social Network Analysis

[EN] Social network analysis (SNA) has not been used to study design project teams in which the full interactions have become more complex (formal and informal) because the team members are from different companies and there is no colocation. This work proposes a method to understand the interactions in the design teams of construction projects using SNA metrics and the sociograms generated within temporary organizations. This study includes three stages: (1) a literature review of the dimensions of interactions within work teams and the application of SNA to the architecture, engineering, and construction (AEC) industry; (2) a proposal of an interaction network method for construction project design teams; and (3) an analysis of a pilot project. Interaction networks were defined in two categories: general interactions and commitment management. For each network, metric indicators were defined for the analysis. The pilot project showed high levels of consistency among team responses. The proposed method allows an analysis of the entire work team and of each individual team member. The method also makes it possible to analyze the work team from a global perspective by carrying out a joint analysis of two or more networks.The authors would like to acknowledge the help and support provided by GEPUC and GEPRO SpA., which provided access to data collection for this study. In addition, the authors acknowledge financial support from FONDECYT (1181648) and the Pontificia Universidad Catolica de Chile. Rodrigo Herrera acknowledges financial support for Ph.D. studies from VRI of PUC and CONICYT-PCHA/National Doctorate/2018-21180884.Herrera, RF.; Mourgues, C.; Alarcón, LF.; Pellicer, E. (2020). Understanding Interactions between Design Team Members of Construction Projects Using Social Network Analysis. Journal of Construction Engineering and Management. 146(6):1-13. https://doi.org/10.1061/(ASCE)CO.1943-7862.0001841S1131466Alarcón D. M. I. M. Alarcón and L. F. Alarcón. 2013. “Social network analysis: A diagnostic tool for information flow in the AEC industry.” In Proc. 21st Annual Conf. of the Int. Group for Lean Construction 2013 947–956. Fortaleza Brazil: International Group for Lean Construction.Alarcón, L. F., Ashley, D. B., de Hanily, A. S., Molenaar, K. R., & Ungo, R. (2011). Risk Planning and Management for the Panama Canal Expansion Program. Journal of Construction Engineering and Management, 137(10), 762-771. doi:10.1061/(asce)co.1943-7862.0000317Al Hattab, M., & Hamzeh, F. (2015). Using social network theory and simulation to compare traditional versus BIM–lean practice for design error management. Automation in Construction, 52, 59-69. doi:10.1016/j.autcon.2015.02.014Austin, R. B., Pishdad-Bozorgi, P., & de la Garza, J. M. (2016). Identifying and Prioritizing Best Practices to Achieve Flash Track Projects. Journal of Construction Engineering and Management, 142(2), 04015077. doi:10.1061/(asce)co.1943-7862.0001061Baiden, B. K., Price, A. D. F., & Dainty, A. R. J. (2006). The extent of team integration within construction projects. International Journal of Project Management, 24(1), 13-23. doi:10.1016/j.ijproman.2005.05.001Cash, P., Dekoninck, E. A., & Ahmed-Kristensen, S. (2017). Supporting the development of shared understanding in distributed design teams. Journal of Engineering Design, 28(3), 147-170. doi:10.1080/09544828.2016.1274719Castillo, T., Alarcón, L. F., & Pellicer, E. (2018). Influence of Organizational Characteristics on Construction Project Performance Using Corporate Social Networks. Journal of Management in Engineering, 34(4), 04018013. doi:10.1061/(asce)me.1943-5479.0000612Castillo, T., Alarcón, L. F., & Salvatierra, J. L. (2018). Effects of Last Planner System Practices on Social Networks and the Performance of Construction Projects. Journal of Construction Engineering and Management, 144(3), 04017120. doi:10.1061/(asce)co.1943-7862.0001443Craft, R. C., & Leake, C. (2002). The Pareto principle in organizational decision making. Management Decision, 40(8), 729-733. doi:10.1108/00251740210437699Dainty, A. R. J., Briscoe, G. H., & Millett, S. J. (2001). Subcontractor perspectives on supply chain alliances. Construction Management and Economics, 19(8), 841-848. doi:10.1080/01446190110089727Dave B. S. Kubler K. Främling and L. Koskela. 2014. “Addressing information flow in lean production management and control in construction.” In Proc. 22nd Annual Conf. of the Int. Group for Lean Construction 581–592. Oslo Norway: International Group for Lean Construction.Flores J. J. C. Ruiz D. Alarcón L. F. Alarcón J. L. Salvatierra and I. Alarcón. 2014. “Improving connectivity and information flow in lean organizations—Towards an evidence-based methodology.” In Proc. 22nd Annual Conf. of the Int. Group for Lean Construction 2014 1109–1120. Oslo Norway: International Group for Lean Construction.Herrera R. F. C. Mourgues and L. F. Alarcón. 2018. “Assessment of lean practices performance and social networks in Chilean airport projects.” In Proc. 26th Annual Conf. of the Int. Group for Lean Construction 2018 603–613. Chennai India: International Group for Lean Construction.Hickethier G. I. D. Tommelein and B. Lostuvali. 2013. “Social network analysis of information flow in an IPD-project design organization.” In Proc. 21st Annual Conf. of the Int. Group for Lean Construction 2013 319–328. Fortaleza Brazil: International Group for Lean Construction.Hoppe, B., & Reinelt, C. (2010). Social network analysis and the evaluation of leadership networks. The Leadership Quarterly, 21(4), 600-619. doi:10.1016/j.leaqua.2010.06.004Karp, N. C., Hauer, K. E., & Sheu, L. (2019). Trusted to Learn: a Qualitative Study of Clerkship Students’ Perspectives on Trust in the Clinical Learning Environment. Journal of General Internal Medicine, 34(5), 662-668. doi:10.1007/s11606-019-04883-1Kereri, J. O., & Harper, C. M. (2019). Social Networks and Construction Teams: Literature Review. Journal of Construction Engineering and Management, 145(4), 03119001. doi:10.1061/(asce)co.1943-7862.0001628Kleinsmann, M., Deken, F., Dong, A., & Lauche, K. (2012). Development of design collaboration skills. Journal of Engineering Design, 23(7), 485-506. doi:10.1080/09544828.2011.619499Knotten, V., Lædre, O., & Hansen, G. K. (2017). Building design management – key success factors. Architectural Engineering and Design Management, 13(6), 479-493. doi:10.1080/17452007.2017.1345718Long D. and P. Arroyo. 2018. “Language moods and improving project performance.” In Proc. 26th Annual Conf. of the Int. Group for Lean Construction 2018 495–504. Chennai India: International Group for Lean Construction.Love, P. E. D., Irani, Z., Cheng, E., & LI, H. (2002). A model for supporting inter-organizational relations in the supply chain. Engineering Construction and Architectural Management, 9(1), 2-15. doi:10.1046/j.1365-232x.2002.00225.xMedina-Mora R. T. Winograd R. Flores and F. Flores. 1992. “The action workflow approach to workflow management technology.” In Proc. Computer Supported Cooperative Work 92 281–288. New York: Association for Computing Machinery.Ng, S. T., & Tang, Z. (2010). Labour-intensive construction sub-contractors: Their critical success factors. International Journal of Project Management, 28(7), 732-740. doi:10.1016/j.ijproman.2009.11.005Oluwatayo, A. A., & Amole, D. (2013). Ownership, structure, and performance of architectural firms. Frontiers of Architectural Research, 2(1), 94-106. doi:10.1016/j.foar.2012.12.001Oviedo-Haito, R. J., Jiménez, J., Cardoso, F. F., & Pellicer, E. (2014). Survival Factors for Subcontractors in Economic Downturns. Journal of Construction Engineering and Management, 140(3), 04013056. doi:10.1061/(asce)co.1943-7862.0000811Paris, C. R., Salas, E., & Cannon-Bowers, J. A. (2000). Teamwork in multi-person systems: a review and analysis. Ergonomics, 43(8), 1052-1075. doi:10.1080/00140130050084879Phelps A. F. 2012. “Behavioral factors influencing lean information flow in complex projects.” In Proc. 20th Annual Conf. of the Int. Group for Lean Construction 2012. San Diego: International Group for Lean Construction.Priven V. and R. Sacks. 2013. “Social network development in Last Planner System implementations.” In Proc. 21st Annual Conf. of the Int. Group for Lean Construction 2013 474–485. Fortaleza Brazil: International Group for Lean Construction.Pryke, S. (2012). Social Network Analysis in Construction. doi:10.1002/9781118443132Rahmawati Y. C. Utomo N. Anwar N. P. Negoro and C. B. Nurcahyo. 2014. “A framework of knowledge management for successful group decision in design process.” In Proc. 2014 IEEE Conf. on Open Systems 60–65. Subang Malaysia: IEEE.Rojas, M. J., Herrera, R. F., Mourgues, C., Ponz-Tienda, J. L., Alarcón, L. F., & Pellicer, E. (2019). BIM Use Assessment (BUA) Tool for Characterizing the Application Levels of BIM Uses for the Planning and Design of Construction Projects. Advances in Civil Engineering, 2019, 1-9. doi:10.1155/2019/9094254Schöttle A. S. Haghsheno and F. Gehbauer. 2014. “Defining cooperation and collaboration in the context of lean construction.” In Proc. 22nd Annual Conf. of the Int. Group for Lean Construction 1269–1280. Oslo Norway: International Group for Lean Construction.Schröpfer, V. L. M., Tah, J., & Kurul, E. (2017). Mapping the knowledge flow in sustainable construction project teams using social network analysis. Engineering, Construction and Architectural Management, 24(2), 229-259. doi:10.1108/ecam-08-2015-0124Scott, J. (2017). Social Network Analysis. doi:10.4135/9781529716597Searle, J. R. (1969). Speech Acts. doi:10.1017/cbo9781139173438Segarra L. R. F. Herrera L. F. Alarcón and E. Pellicer. 2017. “Knowledge management and information flow through social networks analysis in Chilean architecture firms.” In Proc. 25th Annual Conf. of the Int. Group for Lean Construction 413–420. Heraklion Greece: International Group for Lean Construction.Sonnenwald, D. H. (1996). Communication roles that support collaboration during the design process. Design Studies, 17(3), 277-301. doi:10.1016/0142-694x(96)00002-6Svalestuen F. K. Frøystad F. Drevland S. Ahmad J. Lohne and O. Lædre. 2015. “Key elements to an effective building design team.” In Proc. Int. Conf. on Project Management 838–843. Sapporo Japan: Elsevier.Sydow, J., & Braun, T. (2018). Projects as temporary organizations: An agenda for further theorizing the interorganizational dimension. International Journal of Project Management, 36(1), 4-11. doi:10.1016/j.ijproman.2017.04.012Turner, J. R., & Müller, R. (2003). On the nature of the project as a temporary organization. International Journal of Project Management, 21(1), 1-8. doi:10.1016/s0263-7863(02)00020-0Valentine, M. A., Nembhard, I. M., & Edmondson, A. C. (2015). Measuring Teamwork in Health Care Settings. Medical Care, 53(4), e16-e30. doi:10.1097/mlr.0b013e31827feef6Wesz, J. G. B., Formoso, C. T., & Tzortzopoulos, P. (2018). Planning and controlling design in engineered-to-order prefabricated building systems. Engineering, Construction and Architectural Management, 25(2), 134-152. doi:10.1108/ecam-02-2016-0045Wong, P. S. P., Demertjis, M., Hardie, M., & Lo, C. yiu. (2014). The effect of unlearning on organisational learning behaviour and performance in construction contracting organisations. International Journal of Project Organisation and Management, 6(3), 197. doi:10.1504/ijpom.2014.065256Zhang, L., & Ashuri, B. (2018). BIM log mining: Discovering social networks. Automation in Construction, 91, 31-43. doi:10.1016/j.autcon.2018.03.00

Comparing Team Interactions in Traditional and BIM-Lean Design Management

[EN] There is qualitative evidence showing that design teams that use BIM-lean management have a higher level of interaction than design teams that do not use this management approach. However, there is no quantitative empirical evidence of this higher level of interaction. Therefore, the objective of this paper is to present quantitative empirical evidence of the differences among the various types of interactions of a design team. Two case studies were analyzed, and their design management was assessed from a lean BIM perspective while their team interactions were assessed using social network analysis (SNA). To achieve the aim of this paper, four steps were performed: (1) case study selection; (2) description of the design management of the projects from the lean design management and BIM perspectives; (3) assessment of design team interaction; and (4) comparison using SNA. The results show that the project that applied BIM-lean management exhibited higher levels of interactions among its design team members than the traditional team; transparent, orderly, and standardized information flows; a collaborative, trusting, and learning environment; and commitment management. None of these interaction elements were visible in the project that did not apply BIM-lean management. It is suggested that an analysis be performed on a representative sample of projects in the future so that conclusive statistical inferences could be made.This research was funded by Fondecyt Regular, grant number 1210769 and ANID, grant number CONICYT-PCHA/National Doctorate/2018-21180884. The APC was paid by the Pontificia Universidad Católica de Valparaíso.Herrera, RF.; Mourgues, C.; Alarcón, LF.; Pellicer, E. (2021). Comparing Team Interactions in Traditional and BIM-Lean Design Management. Buildings. 11(10):1-25. https://doi.org/10.3390/buildings11100447S125111

Analyzing the Association between Lean Design Management Practices and BIM Uses in the Design of Construction Projects

[EN] There is a beneficial effect when integrating Building Information Modeling (BIM) with lean practices to identify and reduce waste in the construction industry. According to experts, it is possible to improve the design process through waste reduction by implementing lean practices and BIM. An unexplored perspective on these synergies concerns the relationship between the specific uses of BIM and lean practices. Therefore, this study analyzed the relationships between Lean Design Management (LDM) practices and BIM uses in the planning and design phases of the infrastructure lifecycle. To achieve this objective, the research was organized into three stages: (1) the explanation of LDM practices and BIM uses; (2) the characterization of sample projects and data collection strategies; and (3) data exploration, including reliability analysis, descriptive statistics, association analysis, and a causal analysis of LDM practices and BIM uses. The analysis of the relationship between LDM practices and BIM uses generated empirical evidence of the implementation of BIM uses and lean management practices at the design phase. LDM practices from the categories planning and control and problem-solving and decision-making were more related to BIM uses than LDM practices from the category stakeholder management. Additionally, it was concluded that if a project applies a higher proportion of BIM uses, it will tend to apply a higher proportion of LDM practices; however, this relationship is not as clear in the other way around.The authors acknowledge the help and support provided by GEPUC, which provided access to data collection for this study. In addition, the authors acknowledge financial support from FONDECYT (1181648) and the Pontificia Universidad Católica de Chile. Rodrigo Herrera acknowledges financial support for Ph.D. studies from Vicerrectoría de Investigación (VRI) of Pontificia Universidad Católica de Chile (PUC) and CONICYT-PCHA/National Doctorate/2018 -21180884.Herrera, RF.; Mourgues, C.; Alarcón, LF.; Pellicer, E. (2021). Analyzing the Association between Lean Design Management Practices and BIM Uses in the Design of Construction Projects. Journal of Construction Engineering and Management. 147(4):1-11. https://doi.org/10.1061/(ASCE)CO.1943-7862.0002014S1111474Akoglu, H. (2018). User’s guide to correlation coefficients. Turkish Journal of Emergency Medicine, 18(3), 91-93. doi:10.1016/j.tjem.2018.08.001Al Hattab, M., & Hamzeh, F. (2015). Using social network theory and simulation to compare traditional versus BIM–lean practice for design error management. Automation in Construction, 52, 59-69. doi:10.1016/j.autcon.2015.02.014Arayici, Y., Coates, P., Koskela, L., Kagioglou, M., Usher, C., & O’Reilly, K. (2011). Technology adoption in the BIM implementation for lean architectural practice. Automation in Construction, 20(2), 189-195. doi:10.1016/j.autcon.2010.09.016Arroyo, P., Fuenzalida, C., Albert, A., & Hallowell, M. R. (2016). Collaborating in decision making of sustainable building design: An experimental study comparing CBA and WRC methods. Energy and Buildings, 128, 132-142. doi:10.1016/j.enbuild.2016.05.079Bloom, N., & Van Reenen, J. (2007). Measuring and Explaining Management Practices Across Firms and Countries. The Quarterly Journal of Economics, 122(4), 1351-1408. doi:10.1162/qjec.2007.122.4.1351Bloom, N., & Van Reenen, J. (2010). New Approaches to Surveying Organizations. American Economic Review, 100(2), 105-109. doi:10.1257/aer.100.2.105Eastman, C., Teicholz, P., Sacks, R., & Liston, K. (2008). BIM Handbook. doi:10.1002/9780470261309El. Reifi, M. H., & Emmitt, S. (2013). Perceptions of lean design management. Architectural Engineering and Design Management, 9(3), 195-208. doi:10.1080/17452007.2013.802979Fakhimi A. H. J. Majrouhi Sardroud and S. Azhar. 2016. “How can Lean IPD and BIM work together?” In Proc. 33rd Int. Symp. on Automation and Robotics in Construction (ISARC) 1–8. Auburn AL: International Symposium on Automation and Robotics in Construction.Formoso C. T. P. Tzotzopoulos M. S. Jobim and R. Liedtke. 1998. “Developing a protocol for managing the design process in the building industry.” In Proc. 6th Annual Conf. of the Int. Group for Lean Construction. Guarujá Brazil: International Group for Lean Construction.Gambatese, J. A., Pestana, C., & Lee, H. W. (2017). Alignment between Lean Principles and Practices and Worker Safety Behavior. Journal of Construction Engineering and Management, 143(1), 04016083. doi:10.1061/(asce)co.1943-7862.0001209Gerber D. J. B. Becerik-Gerber and A. Kunz. 2010. “Building information modeling and Lean Construction: Technology methodology and advances from practices.” In Proc. 18th Annual Conf. of the Int. Group for Lean Construction 1–11. Haifa Israel: International Group for Lean Construction.Gu, N., & London, K. (2010). Understanding and facilitating BIM adoption in the AEC industry. Automation in Construction, 19(8), 988-999. doi:10.1016/j.autcon.2010.09.002Koskela L. 2000. “An exploration towards a production theory and its application to construction.” Ph.D. thesis Dept. of Technology Technical Research Centre of Finland.Koskela L. G. Ballard and V. P. Tanhuanpää. 1997. “Towards lean design management.” In Proc. 5th Annual Conf. of the Int. Group for Lean Construction 1997 1–13. Gold Coast Australia: International Group for Lean Construction.Liu, Y., van Nederveen, S., & Hertogh, M. (2017). Understanding effects of BIM on collaborative design and construction: An empirical study in China. International Journal of Project Management, 35(4), 686-698. doi:10.1016/j.ijproman.2016.06.007Matta G. R. F. Herrera C. Baladrón Z. Giménez and L. F. Alarcón. 2018. “Using BIM-based sheets as a visual management tool for on-site instructions: A case study.” In Vol. 1 of Proc. 26th Annual Conf. of the Int. Group for Lean Construction: Evolving Lean Construction Towards Mature Production Management Across Cultures and Frontiers 144–154.Mesa, H. A., Molenaar, K. R., & Alarcón, L. F. (2016). Exploring performance of the integrated project delivery process on complex building projects. International Journal of Project Management, 34(7), 1089-1101. doi:10.1016/j.ijproman.2016.05.007Mok, K. Y., Shen, G. Q., & Yang, J. (2015). Stakeholder management studies in mega construction projects: A review and future directions. International Journal of Project Management, 33(2), 446-457. doi:10.1016/j.ijproman.2014.08.007Molwus, J. J., Erdogan, B., & Ogunlana, S. (2017). Using structural equation modelling (SEM) to understand the relationships among critical success factors (CSFs) for stakeholder management in construction. Engineering, Construction and Architectural Management, 24(3), 426-450. doi:10.1108/ecam-10-2015-0161Munthe-Kaas T. S. H. Hjelmbrekke and J. Lohne. 2015. “Lean design versus traditional design approach.” In Proc. 23th Annual Conf. Int. Group for Lean Construction 578–588. Perth Australia: International Group for Lean Construction.Nascimento, D., Caiado, R., Tortorella, G., Ivson, P., & Meiriño, M. (2018). Digital Obeya Room: exploring the synergies between BIM and lean for visual construction management. Innovative Infrastructure Solutions, 3(1). doi:10.1007/s41062-017-0125-0Olatunji, O. A. (2011). Modelling the costs of corporate implementation of building information modelling. Journal of Financial Management of Property and Construction, 16(3), 211-231. doi:10.1108/13664381111179206Porwal, A., & Hewage, K. N. (2013). Building Information Modeling (BIM) partnering framework for public construction projects. Automation in Construction, 31, 204-214. doi:10.1016/j.autcon.2012.12.004Ragin, C. C. (2006). Set Relations in Social Research: Evaluating Their Consistency and Coverage. Political Analysis, 14(3), 291-310. doi:10.1093/pan/mpj019Sacks R. R. Barak B. Belaciano and U. Gurevich. 2011. “Field tests of the KanBIM lean production management system.” In Proc. 19th Annual Conf. of the Int. Group for Lean Construction 1–12. Lima Perú: International Group for Lean Construction.Sacks, R., Koskela, L., Dave, B. A., & Owen, R. (2010). Interaction of Lean and Building Information Modeling in Construction. Journal of Construction Engineering and Management, 136(9), 968-980. doi:10.1061/(asce)co.1943-7862.0000203Schimanski C. P. G. P. Monizza C. Marcher and D. T. Matt. 2019. “Conceptual foundations for a new lean BIM-based production system in construction.” In Proc. 27th Annual Conf. of the Int. Group for Lean Construction 877–888. Dublin Ireland: International Group for Lean Construction.Schneider, C. Q., & Wagemann, C. (2012). Set-Theoretic Methods for the Social Sciences. doi:10.1017/cbo9781139004244Succar B. 2016. “211in model uses list.” Accessed March 1 2020. https://bimexcellence.org/wp-content/uploads/211in-Model-Uses-Table.pdf.Succar, B., Sher, W., & Williams, A. (2012). Measuring BIM performance: Five metrics. Architectural Engineering and Design Management, 8(2), 120-142. doi:10.1080/17452007.2012.659506Tsai, M.-H., Mom, M., & Hsieh, S.-H. (2014). Developing critical success factors for the assessment of BIM technology adoption: part I. Methodology and survey. Journal of the Chinese Institute of Engineers, 37(7), 845-858. doi:10.1080/02533839.2014.88881

Numerical simulation of needle movement nozzle flow coupled with spray for a diesel injector using an Eulerian spray atomization model

[EN] The injector dynamics have a strong impact on spray behavior, therefore on combustion efficiency and pollutant emissions. Nozzle flow and spray coupled simulations are useful tools to analyze the effect of nozzle geometry, and they could be used also to study the effect of needle movement. In this work, three different approximations to the same needle lift law are employed in an Eulerian Spray Atomization (ESA) model. The main advantage of this model is that is able to simulate nozzle flow and spray seamlessly. Engine Combustion Network (ECN) Spray A conditions are simulated. Results show that the experimental needle lift law can be used without any fitting to a smoothed expression, but all details of the needle dynamics must be considered in order to properly predict mass flow rate and spray penetration. Additionally, it has been shown that needle dynamics has a strong impact on heating effects inside the nozzle.This research was performed in the frame of the project "Estudio de la interaccion chorro-pared en condiciones realistas de motor (SPRAY WALL)" reference TRA2015-67679-c2-1-R from Ministerio de Economia y Competitividad (Spanish Ministry of Economy).Payri, R.; Gimeno, J.; Marti-Aldaravi, P.; Alarcón-Herrera, MY. (2017). Numerical simulation of needle movement nozzle flow coupled with spray for a diesel injector using an Eulerian spray atomization model. Journal of the Brazilian Society of Mechanical Sciences and Engineering. 7(39):2585-2592. https://doi.org/10.1007/s40430-017-0801-1S25852592739Fajgenbaum R, dos Santos RG (2016) Influence of fuel temperature on atomization parameters in a pressure-swirl atomizer from a port fuel injector by Shadowgraphy technique. J Braz Soc Mech Sci Eng 38:1877–1892. doi: 10.1007/s40430-015-0443-0He Z, Guo G, Tao X, Zhong W, Leng X, Wang Q (2016) Study of the effect of nozzle hole shape on internal flow and spray characteristics. Int Commun Heat Mass Transf 71:1–8. doi: 10.1016/j.icheatmasstransfer.2015.12.002Loaiza JCV, Sánchez FZ, Braga SL (2016) Combustion study of reactivity-controlled compression ignition (RCCI) for the mixture of diesel fuel and ethanol in a rapid compression machine. J Braz Soc Mech Sci Eng 38:1073–1085. doi: 10.1007/s40430-015-0400-ySalvador FJ, Romero JV, Roselló MD, Jaramillo D (2015) Numerical simulation of primary atomization in diesel spray at low injection pressure. J Comput Appl Math 291:94–102. doi: 10.1016/j.cam.2015.03.044Strotos G, Koukpuvinis P, Theodorakakos A (2015) Transient heating effects in high pressure Diesel injector nozzles. Int J Heat Fluid Flow 51:257–267. doi: 10.1016/j.ijheatfluidflow.2014.10.010Macian V, Bermúdez V, Payri R, Gimeno J (2003) New technique for determination of internal geometry of a Diesel nozzle with the use of silicone methodology. Exp Tech 39:39–43. doi: 10.1111/j.1747-1567.2003.tb00107.xKastengren AL, Tiloco FZ, Powell CF, Manin J, Pickett LM, Payri R, Bazyn T (2013) Engine combustion network (ECN): measurements of nozzle geometry and hydraulic behavior. Atom Sprays 22:1011–1052. doi: 10.1615/AtomizSpr.006309Kastengren AL, Tiloco FZ, Duke DJ, Powell CF, Zhang X, Moon S (2014) Time-resolved X-ray radiography of sprays from engine combustion network Spray A diesel injectors. Atom Sprays 24:251–272. doi: 10.1615/AtomizSpr.2013008642Payri R, Gimeno J, Viera JP, Plazas AH (2013) Needle lift profile influence on the vapor phase penetration for a prototype diesel direct acting piezoelectric injector. Fuel 113:257–265. doi: 10.1016/j.fuel.2013.05.057Lee WG, Reitz RD (2009) A numerical investigation of transient flow and cavitation within Minisac and VCO Diesel injector nozzles. In: Proceedings of the 2009 spring technical conference of the ASME internal combustion engine division, pp 643–653. doi: 10.1115/ICES2009-76148Bermúdez V, Payri R, Salvador FJ, Plazas AH (2005) Study of the influence of nozzle seat type on injection rate and spray behavior. IMechE. Part D. J Autom Eng 219:677–689. doi: 10.1243/095440705X28303Vallet A, Burluka AA, Borghi R (2001) Development of a Eulerian model for the “Atomization” of a liquid jet. Atom Sprays 11:619–642. doi: 10.1615/AtomizSpr.v11.i6.20García-Oliver JM, Pastor JM, Pandal A, Trask N, Baldwing E (2013) Diesel Spray CFD simulations based on the $$\Sigma$$ Σ - $$Y$$ Y Eulerian atomization model. Atom Sprays 23:71–95. doi: 10.1615/AtomizSpr.007198Bardi M, Payri R, Malbec LM, Bruneaux G, Pickett LM, Manin J, Bazyn T, Genzale C (2012) Engine combustion network: comparison of spray development, vaporization, and combustion in different combustion vessels. Atom Sprays 22:807–842. doi: 10.1615/AtomizSpr.2013005837Kösters A, Karlsson A (2016) Validation of the VSB2 spray model against Spray A and Spray H. Atom Sprays 26(8):775–798. doi: 10.1615/AtomizSpr.2015011670Salvador FJ, Gimeno J, Pastor JM, Martí-Aldaraví P (2015) Effect of turbulence model and inlet boundary condition on the Diesel spray behavior by an Eulerian spray atomization (ESA) model. Int J Multiph Flow 65:108–116. doi: 10.1016/j.ijmultiphaseflow.2014.06.003Desantes JM, García-Oliver JM, Pastor JM, Pandal A, Baldwin E, Shcmidt DP (2015) Coupled/decoupled spray simulation comparison of the ECN spray A condition with the $$\Sigma$$ Σ - $$Y$$ Y Eulerian atomization model. Int J Multiph Flow 80:89–99. doi: 10.1016/j.ijmultiphaseflow.2015.12.002Petranović Z, Edelbauer W, Vujanović M, Duić N (2016) Modelling of spray and combustion processes by using the Eulerian multiphase approach and detailed chemical kinetics. Fuel 191:25–35. doi: 10.1016/j.fuel.2016.11.051Anvari S, Taghavifar H, Khalilarya S, Jafarmadar S (2016) Numerical simulation of diesel injector nozzle flow and in-cylinder spray evolution. Appl Math Model 40:8617–8629. doi: 10.1016/j.apm.2016.05.017Desantes JM, Payri R, Gimeno J, Martí-Aldaraví P (2014) Simulation of the first millimeters of the diesel Spray by an Eulerian spray atomization model applied on ECN Spray A injector. SAE Technical Paper 2014-01-1418. doi: 10.4271/2014-01-1418Payri R, Ruiz S, Gimeno J, Martí-Aldaraví P (2015) Verification of a new CFD compressible segregated and multi-phase solver with different flux update-equations sequences. 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Solar desalination by combination with concentrated solar power: Exergy cost analysis

Some regions of the world with high solar irradiation conditions have a growing demand for electricity and freshwater that could cause supply problems in the industries and population. To reduce this risk, the use of solar energy to generate electricity and freshwater is an interesting option to consider. Electricity could be generated from concentrated solar power (CSP) plants fuelled by solar energy and natural gas, while freshwater could be produced from multi-effect distillation (MED) and reverse osmosis (RO) technologies driven by thermal energy and electricity, respectively. An exergy cost analysis of the integration of two desalination technologies (MED and RO) with a CSP plant is carried out to compare in terms of exergy cost. The symbolic exergoeconomics method is applied in the configurations analyzed. The different configurations are evaluated in a representative region with high irradiation conditions. Results show that the best configuration for producing electricity and freshwater is achieved when the stand-alone RO plant is connected to the grid where the unit exergy cost of electricity and water is 31% and 54% lower than in the stand-alone CSP plant and stand-alone MED, respectively. However, CSP-MED is the recommended configuration for the solar cogeneration scheme evaluated. Additionally, the most influential components in the cost formation of electricity are solar collectors (46.6% in CSP-MED and 44.3% in CSP-RO) while for freshwater they are solar collectors (27.6% in CSP-MED and 42.0% CSP-RO), multi-effect distillation module (15.7% in CSP-MED), and reverse osmosis module (20.5% in CSP-RO). In these components the design should be improved to reduce the unit exergy cost of electricity and freshwater

La encrucijada bioética del sistema de salud colombiano: entre el libre mercado y la regulación estatal

El artículo analiza la crisis del sistema de salud colombiano sometido al modelo de economía de mercado con regulación estatal a partir de la Ley 100 de 1993. Su interés se centra en reflexionar sobre la concepción que el modelo da al gasto en salud como una inversión sometida a las fuerzas del mercado y consecuencialmente, con una tasa de rentabilidad esperada. Mediante el análisis de estadísticas oficiales y de encuestas de satisfacción de los usuarios se devela la crisis estructural que padece la prestación del servicio de salud pública como un sistema, involucrando variables económicas, políticas y sociales. La interdisciplinariedad del abordaje temático del estudio permite profundizar en el análisis desde la reflexión de los valores morales y éticos que debe acompañar la asistencia sanitaria, al igual que la visión económica de su administración. Bioética, salud y economía constituyen descriptores fácticos de un sistema en crisis estructural que alimenta la patología social de la pobreza