El valor que agrega la escuela: una aproximación a la calidad de la educación en Colombia

El artículo presenta nuevas formas de abordar los resultados de estudiantes y colegios en los exámenes de estado del ICFES. Incorporando las críticas recibidas por diferentes publicaciones, en donde se comparan los colegios de acuerdo al puntaje promedio obtenido por cada uno de ellos, se propone un análisis de valor agregado, el cual tiene en cuenta de manera explícita las diferencias en el contexto socioeconómico de los estudiantes y sus familias, para abordar de manera más equitativa los resultados académicos. Se muestra la bondad de esta técnica para efectos del diagnóstico y diseño de estrategias de mejoramiento tanto a nivel de los colegios como al interior de ellos, al poder explorar los resultados de cada uno de sus estudiantes. ************************************************************************ The article presents new forms to undertake the results of students and schools in the ICFES exam. Incorporating the criticisms of different publications where are compared the schools according to the score average obtained by each one of them, an analysis of aggregate value is proposed, which keeps in mind in an explicit way the differences in the socioeconomic status of the students and its families, to undertake of fairer way the academic results. The kindness of this technique for effects of the diagnosis and design of strategies of improvement is shown, so much to level of the schools as to the inside of them, to explore the results of each one of its students.ICFES, calidad de la eduación, tablas de desempeño, valor agregado

Optimal Location and Operation of PV Sources in DC Grids to Reduce Annual Operating Costs While Considering Variable Power Demand and Generation

Due to the need to include renewable energy resources in electrical grids as well as the development and high implementation of PV generation and DC grids worldwide, it is necessary to propose effective optimization methodologies that guarantee that PV generators are located and sized on the DC electrical network. This will reduce the operation costs and cover the investment and maintenance cost related to the new technologies (PV distributed generators), thus satisfying all technical and operative constraints of the distribution grid. It is important to propose solution methodologies that require short processing times, with the aim of exploring a large number of scenarios while planning energy projects that are to be presented in public and private contracts, as well as offering solutions to technical problems of electrical distribution companies within short periods of time. Based on these needs, this paper proposes the implementation of a Discrete–Continuous Parallel version of the Particle Swarm Optimization algorithm (DCPPSO) to solve the problem regarding the integration of photovoltaic (PV) distributed generators (DGs) in Direct Current (DC) grids, with the purpose of reducing the annual costs related to energy purchasing as well as the investment and maintenance cost associated with PV sources in a scenario of variable power demand and generation. In order to evaluate the effectiveness, repeatability, and robustness of the proposed methodology, four comparison methods were employed, i.e., a commercial software and three discrete–continuous methodologies, as well as two test systems of 33 and 69 buses. In analyzing the results obtained in terms of solution quality, it was possible to identify that the DCPPSO proposed obtained the best performance in relation to the comparison methods used, with excellent results in relation to the processing times and standard deviation. The main contribution of the proposed methodology is the implementation of a discrete–continuous codification with a parallel processing tool for the evaluation of the fitness function. The results obtained and the reports in the literature for alternating current networks demonstrate that the DCPPSO is the optimization methodology with the best performance in solving the problem of the optimal integration of PV sources in economic terms and for any kind of electrical system and size. © 2022 by the authors

An Effective Power Dispatch of Photovoltaic Generators in DC Networks via the Antlion Optimizer

This paper studies the problem regarding the optimal power dispatch of photovoltaic (PV) distributed generators (DGs) in Direct Current (DC) grid-connected and standalone networks. The mathematical model employed considers the reduction of operating costs, energy losses, and CO2 emissions as objective functions, and it integrates all technical and operating constraints implied by DC grids in a scenario of variable PV generation and power demand. As a solution methodology, a master–slave strategy was proposed, whose master stage employs Antlion Optimizer (ALO) for identifying the values of power to be dispatched by each PV-DG installed in the grid, whereas the slave stage uses a matrix hourly power flow method based on successive approximations to evaluate the objective functions and constraints associated with each solution proposed within the iterative process of the ALO. Two test scenarios were considered: a grid-connected network that considers the operating characteristics of the city of Medellín, Antioquia, and a standalone network that uses data from the municipality of Capurganá, Chocó, both of them located in Colombia. As comparison methods, five continuous optimization methods were used which were proposed in the specialized literature to solve optimal power flow problems in DC grids: the crow search algorithm, the particle swarm optimization algorithm, the multiverse optimization algorithm, the salp swarm algorithm, and the vortex search algorithm. The effectiveness of the proposed method was evaluated in terms of the solution, its repeatability, and its processing times, and it obtained the best results with respect to the comparison methods for both grid types. The simulation results obtained for both test systems evidenced that the proposed methodology obtained the best results with regard to the solution, with short processing times for all of the objective functions analyzed

Mezclas de cera y bentonita para el desarrollo de arcilla industrial de prototipado: resultados preliminares

The automotive design process and the materials in the automotive industry in recent years has caused great interest to the industrial and academic sector. In this study was to evaluate the effect of the amount of bentonite on the thermal and rheological properties of the compound bentonite / paraffin wax. Two bentonite ratios were used: paraffin wax (40:60 and 30:70). The paraffin was characterized by Fourier transform infrared spectroscopy (FTIR), the bentonite was characterized by means of x-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray fluorescence (XRF). The bentonite/paraffine wax composite was characterized by differential-scanning calorimetry (DSC) and rheology. The sample that contains a higher amount of bentonite shows a lower latent heat, and this could cause a greater heat transfer. Finally, the sample that has a lower amount of bentonite evidenced a lower viscosity, and it could be related to a lower interaction between the particles. The sample S1 due to its lower latent heat compared to S2 could represent an interesting alternative to develop prototypingclays. since these materials are characterized by their low working temperatures and easy malleability. Keywords: automotive, prototyping, latent heat, bentonite, paraffin. References [1]X. Ferràs-Hernández, E. Tarrats-Pons, and N. Arimany-Serrat, “Disruption in the automotive industry: A Cambrian moment,” Bus. Horiz., vol. 60, no. 6, pp.855–863, 2017, doi: 10.1016/j.bushor.2017.07.011. [2]O. Heneric, G. Licht, S. Lutz, and W. Urban, “The Europerean Automotive Industry in a Global Context,” Eur. Automot. Ind. Move, pp. 5–44, 2005, doi: 10.1007/3-7908-1644-2_2. [3]S. I.-N. Delhi, “Automotive Revolution & Perspective Towards 2030,” Auto Tech Rev., vol. 5, no. 4, pp. 20–25, Apr. 2016, doi: 10.1365/s40112-016-1117-8.[4]M. Tovey, J. Owen, and P. Street, “in Automotive Design,” vol. 21, pp. 569–588, 2000. [5]Yasusato Yamada, Clay modeling : techniques for giving three-dimensional form to idea. 1997. [6]H. Murray, “Industrial clays case study,” Mining, Miner. Sustain. Dev., vol. 1, no. 64, pp. 1–9, 2002, [Online]. Available: http://www.whitemudresources.com/public/Hayn Murray Clays Case Study.pdf%0Ahttp://whitemudresources.com/public/Hayn Murray ClaysCase Study.pdf. [7]Transparency Market Research, “Industrial Clay Market - Global Industry Analysis, Size, Share, Growth, Trends, and Forecast 2016 - 2024,” New york, 2016.[8]J. Murphy, Additives for Plastics Handbook. Elsevier, 2001. [9]Y. Hong, J. J. Cooper-White, M. E. Mackay, C. J. Hawker, E. Malmström, and N. Rehnberg, “A novel processing aid for polymer extrusion: Rheology and processing of polyethylene and hyperbranched polymer blends,” J. Rheol. (N. Y. N. Y)., vol. 43, no. 3, pp. 781–793, 1999, doi: 10.1122/1.550999. [10]D. P. Rawski, P. Edwards, and U. States, “Pulp and Paper : Non fi brous Components,” no. January, pp.1–4, 2017, doi: 10.1016/B978-0-12-803581-8.10289-9. [11]J. Speight, “Instability and incompatibility of tight oil and shale oil,” Shale Oil Gas Prod. Process., pp. 915–942, 2020, doi: 10.1016/b978-0-12-813315-6.00017-8. [12]T. P. Brown, L. Rushton, M. A. Mugglestone, and D. F. Meechan, “Health effects of a sulphur dioxide air pollution episode,” vol. 25, no. 4, pp. 369–371, 2003,doi: 10.1093/pubmed/fdg083. [13]R. Chihi, I. Blidi, M. Trabelsi-Ayadi, and F. Ayari, “Elaboration and characterization of a low-cost porous ceramic support from natural Tunisian bentonite clay,” Comptes Rendus Chim., vol. 22, no. 2–3, pp. 188–197, 2019, doi: 10.1016/j.crci.2018.12.002. [14]Z. Yi, W. Xiaopeng, and L. I. Dongxu, “Prepartion of organophilic bentonite / paraffin composite phase change energy storage material with melting intercalation method,” pp. 126–131, 2011, doi: 10.4028/www.scientific.net/AMR.284-286.126. [15]I. Krupa and A. S. Luyt, “Thermal and mechanical properties of extruded LLDPE / wax blends,” vol. 73, pp. 157–161, 2001. [16]A. Saleem, L. Frormann, J. Koltermann, and C. Reichelt, “Fabrication and Processing of Polypropylene - Paraffin Compounds with Enhanced Thermal andProcessing Properties : Impact Penetration and Thermal Characterization,” vol. 40164, pp. 1–9, 2014, doi:10.1002/app.40164. [17]M. Mu, P. A. M. Basheer, W. Sha, Y. Bai, and T. Mcnally, “Shape stabilised phase change materials based on a high melt viscosity HDPE and paraffin waxes,”Appl. Energy, vol. 162, pp. 68–82, 2016, doi: 10.1016/j.apenergy.2015.10.030. [18]M. Tovey, “Intuitive and objective processes in automotive design,” Des. Stud., vol. 13, no. 1, pp. 23–41, 1992, doi: 10.1016/0142-694X(92)80003-H. [19]J. Verlinden, A. Kooijman, E. Edelenbos, and C. Go, “Investigation on the use of illuminated clay in automotive styling,” 6th Int. Conf. Comput. Ind. Des.Concept. Des. (CAID&CD), Delft, NETHERLANDS, pp. 514–519, 2005. [20]N. W. Muhamad Bustaman and M. S. Abu Mansor, “A Study on CAD/CAM Application in CNC Milling Using Industrial Clay,” Appl. Mech. Mater., vol. 761, pp. 32–36, 2015, doi: 10.4028/www.scientific.net/AMM.761.32. [21]K. Shimokawa, Japan and the global automotive industry. 2010. [22]A. Bucio, R. Moreno tovar, L. Bucio, J. Espinosadávila, and F. Anguebes franceschi, “Characterization of beeswax, candelilla wax and paraffin wax for coatingcheeses,” Coatings, vol. 11, no. 3, pp. 1–18, 2021, doi: 10.3390/coatings11030261. [23]F. Valentini, A. Dorigato, A. Pegoretti, M. Tomasi, G. D. Sorarù, and M. Biesuz, “Si3N4 nanofelts/paraffin composites as novel thermal energy storage architecture,” J. Mater. Sci., vol. 56, no. 2, pp. 1537–1550, 2021, doi: 10.1007/s10853-020-05247-5. [24]F. Paquin, J. Rivnay, A. Salleo, N. Stingelin, and C. Silva, “Multi-phase semicrystalline microstructures drive exciton dissociation in neat plastic semiconductors,” J. Mater. Chem. C, vol. 3, pp. 10715–10722, 2015, doi: 10.1039/b000000x. [25]R. S. Hebbar, A. M. Isloor, B. Prabhu, Inamuddin, A. M. Asiri, and A. F. Ismail, “Removal of metal ions and humic acids through polyetherimide membranewith grafted bentonite clay,” Sci. Rep., vol. 8, no. 1, 2018, doi: 10.1038/s41598-018-22837-1. [26]S. Betancourt-Parra, M. A. Domínguez-Ortiz, and M. Martínez-Tejada, “Colombian clays binary mixtures: Physical changes due to thermal treatments,” DYNA, vol. 87, no. 212, pp. 73–79, 2020, doi: 10.15446/dyna.v87n212.82285. [27]A. M. Rabie, E. A. Mohammed, and N. A. Negm, “Feasibility of modified bentonite as acidic heterogeneous catalyst in low temperature catalytic crackingprocess of biofuel production from nonedible vegetable oils,” J. Mol. Liq., vol. 254, no. 2018, pp. 260–266, 2018, doi: 10.1016/j.molliq.2018.01.110. [28]A. Kadeche et al., “Preparation, characterization and application of Fe-pillared bentonite to the removal of Coomassie blue dye from aqueous solutions,” Res. Chem. Intermed., vol. 46, no. 11, pp. 4985–5008, 2020, doi: 10.1007/s11164-020-04236-2. [29]C. I. R. De Oliveira, M. C. G. Rocha, A. L. N. DaSilva, and L. C. Bertolino, “Characterization of bentonite clays from Cubati, Paraíba Northeast of Brazil,” Ceramica, vol. 62, no. 363, pp. 272–277, 2016, doi:10.1590/0366-69132016623631970. [30]I. Z. Hager, Y. S. Rammah, H. A. Othman, E. M. Ibrahim, S. F. Hassan, and F. H. Sallam, “Nano-structured natural bentonite clay coated by polyvinyl alcohol polymer for gamma rays attenuation,” J. Theor. Appl. Phys., vol. 13, no. 2, pp. 141–153, 2019, doi: 10.1007/ s40094-019-0332-5. [31]A. Tebeje, Z. Worku, T. T. I. Nkambule, and J. Fito, “Adsorption of chemical oxygen demand from textile industrial wastewater through locally prepared bentonite adsorbent,” Int. J. Environ. Sci. Technol., no. 0123456789, 2021, doi: 10.1007/s13762-021-03230-4. [32]F. E. Özgüven, A. D. Pekdemir, M. Önal, and Y. Sarıkaya, “Characterization of a bentonite and its permanent aqueous suspension,” J. Turkish Chem. Soc.Sect. A Chem., vol. 7, no. 1, pp. 11–18, 2019, doi: 10.18596/jotcsa.535937. [33]S. Tao, S. Wei, and Y. Yulan, “Characterization of Expanded Graphite Microstructure and Fabrication of Composite Phase-Change Material for Energy Storage,” J. Mater. Civ. Eng., vol. 27, no. 4, p. 04014156, 2015, doi: 10.1061/(asce)mt.1943-5533.0001089. [34]M. Li, Z. Wu, H. Kao, and J. Tan, “Experimental investigation of preparation and thermal performances of paraffin/bentonite composite phase change material,” Energy Convers. Manag., vol. 52, no. 11, pp. 3275–3281, 2011, doi: 10.1016/j.enconman.2011.05.015. [35]S. M. Hosseini, E. Ghasemi, A. Fazlali, and D. E. Henneke, “The effect of nanoparticle concentration on the rheological properties of paraffin-based Co3O4 ferrofluids,” J. Nanoparticle Res., vol. 14, no. 7, 2012, doi: 10.1007/s11051-012-0858-9.El proceso de diseño automotriz y los materiales en la industria automotriz pen los últimos años ha despertado un gran interés en el sector industrial y académico. En este estudio se evaluó el efecto de la cantidad de bentonita sobre las propiedades térmicas y reológicas del compuesto bentonita/ cera de parafina. Se utilizaron dos proporciones de bentonita: cera de parafina (40:60 y 30:70). La parafina se caracterizó por espectroscopia infrarroja por transformada de Fourier (FTIR), la bentonita se caracterizó mediante difracción de rayos X (XRD), análisis termogravimétrico (TGA), fluorescencia de rayos X (XRF). El compuesto de cera de bentonita / parafina se caracterizó por calorimetría de barrido diferencial (DSC) y reología. La muestra que contiene una mayor cantidad de bentonita presenta un menor calor latente, y esto podría provocar una mayor transferencia de calor. Finalmente, la muestra que tiene menor cantidad de bentonita evidenció una menor viscosidad, y podría estar relacionado con una menor interacción entre las partículas. La muestra S1 debido a su menor calor latente en comparación con S2 podría representar una alternativa interesante para desarrollar arcillas de prototipado. Ya que estos materiales S3 caracterizan por sus bajas temperaturas de trabajo y fácil maleabilidad. Palabras clave: automóvil, prototipado, reología, bentonita, parafina. Referencias [1]X. Ferràs-Hernández, E. Tarrats-Pons, y N. Arimany-Serrat, “Disruption in the automotive industry: A Cambrian moment,” Bus. Horiz., vol. 60, no. 6, pp.855–863, 2017, doi: 10.1016/j.bushor.2017.07.011. [2]O. Heneric, G. Licht, S. Lutz, y W. Urban, “The Europerean Automotive Industry in a Global Context,” Eur. Automot. Ind. Move, pp. 5–44, 2005, doi: 10.1007/3-7908-1644-2_2. [3]S. I.-N. Delhi, “Automotive Revolution & Perspective Towards 2030,” Auto Tech Rev., vol. 5, no. 4, pp. 20–25, Apr. 2016, doi: 10.1365/s40112-016-1117-8. [4]M. Tovey, J. Owen, y P. Street, “in Automotive Design,” vol. 21, pp. 569–588, 2000. [5]Yasusato Yamada, Clay modeling : techniques for giving three-dimensional form to idea. 1997. [6]H. Murray, “Industrial clays case study,” Mining, Miner. Sustain. Dev., vol. 1, no. 64, pp. 1–9, 2002, [En línea]. Disponible en: http://www.whitemudresources.com/public/Hayn Murray Clays Case Study.pdf%0Ahttp://whitemudresources.com/public/Hayn Murray ClaysCase Study.pdf. [7]Transparency Market Research, “Industrial Clay Market - Global Industry Analysis, Size, Share, Growth, Trends, and Forecast 2016 - 2024,” New york, 2016.[8]J. Murphy, Additives for Plastics Handbook. Elsevier, 2001. [9]Y. Hong, J. J. Cooper-White, M. E. Mackay, C. J. Hawker, E. Malmström, y N. Rehnberg, “A novel processing aid for polymer extrusion: Rheology and processing of polyethylene and hyperbranched polymer blends,” J. Rheol. (N. Y. N. Y)., vol. 43, no. 3, pp. 781–793, 1999, doi: 10.1122/1.550999. [10]D. P. Rawski, P. Edwards, y U. States, “Pulp and Paper : Non fi brous Components,” no. January, pp.1–4, 2017, doi: 10.1016/B978-0-12-803581-8.10289-9. [11]J. Speight, “Instability and incompatibility of tight oil and shale oil,” Shale Oil Gas Prod. Process., pp. 915–942, 2020, doi: 10.1016/b978-0-12-813315-6.00017-8. [12]T. P. Brown, L. Rushton, M. A. Mugglestone, y D. F. Meechan, “Health effects of a sulphur dioxide air pollution episode,” vol. 25, no. 4, pp. 369–371, 2003,doi: 10.1093/pubmed/fdg083. [13]R. Chihi, I. Blidi, M. Trabelsi-Ayadi, y F. Ayari, “Elaboration and characterization of a low-cost porous ceramic support from natural Tunisian bentonite clay,” Comptes Rendus Chim., vol. 22, no. 2–3, pp. 188–197, 2019, doi: 10.1016/j.crci.2018.12.002. [14]Z. Yi, W. Xiaopeng, y L. I. Dongxu, “Prepartion of organophilic bentonite / paraffin composite phase change energy storage material with melting intercalation method,” pp. 126–131, 2011, doi: 10.4028/www.scientific.net/AMR.284-286.126. [15]I. Krupa y A. S. Luyt, “Thermal and mechanical properties of extruded LLDPE / wax blends,” vol. 73, pp. 157–161, 2001. [16]A. Saleem, L. Frormann, J. Koltermann, y C. Reichelt, “Fabrication and Processing of Polypropylene - Paraffin Compounds with Enhanced Thermal andProcessing Properties : Impact Penetration and Thermal Characterization,” vol. 40164, pp. 1–9, 2014, doi:10.1002/app.40164. [17]M. Mu, P. A. M. Basheer, W. Sha, Y. Bai, y T. Mcnally, “Shape stabilised phase change materials based on a high melt viscosity HDPE and paraffin waxes,”Appl. Energy, vol. 162, pp. 68–82, 2016, doi: 10.1016/j.apenergy.2015.10.030. [18]M. Tovey, “Intuitive and objective processes in automotive design,” Des. Stud., vol. 13, no. 1, pp. 23–41, 1992, doi: 10.1016/0142-694X(92)80003-H. [19]J. Verlinden, A. Kooijman, E. Edelenbos, y C. Go, “Investigation on the use of illuminated clay in automotive styling,” 6th Int. Conf. Comput. Ind. Des.Concept. Des. (CAID&CD), Delft, NETHERLANDS, pp. 514–519, 2005. [20]N. W. Muhamad Bustaman y M. S. Abu Mansor, “A Study on CAD/CAM Application in CNC Milling Using Industrial Clay,” Appl. Mech. Mater., vol. 761, pp. 32–36, 2015, doi: 10.4028/www.scientific.net/AMM.761.32. [21]K. Shimokawa, Japan and the global automotive industry. 2010. [22]A. Bucio, R. Moreno tovar, L. Bucio, J. Espinosadávila, y F. Anguebes franceschi, “Characterization of beeswax, candelilla wax and paraffin wax for coatingcheeses,” Coatings, vol. 11, no. 3, pp. 1–18, 2021, doi: 10.3390/coatings11030261. [23]F. Valentini, A. Dorigato, A. Pegoretti, M. Tomasi, G. D. Sorarù, y M. Biesuz, “Si3N4 nanofelts/paraffin composites as novel thermal energy storage architecture,” J. Mater. Sci., vol. 56, no. 2, pp. 1537–1550, 2021, doi: 10.1007/s10853-020-05247-5. [24]F. Paquin, J. Rivnay, A. Salleo, N. Stingelin, y C. Silva, “Multi-phase semicrystalline microstructures drive exciton dissociation in neat plastic semiconductors,” J. Mater. Chem. C, vol. 3, pp. 10715–10722, 2015, doi: 10.1039/b000000x. [25]R. S. Hebbar, A. M. Isloor, B. Prabhu, Inamuddin, A. M. Asiri, y A. F. Ismail, “Removal of metal ions and humic acids through polyetherimide membranewith grafted bentonite clay,” Sci. Rep., vol. 8, no. 1, 2018, doi: 10.1038/s41598-018-22837-1. [26]S. Betancourt-Parra, M. A. Domínguez-Ortiz, y M. Martínez-Tejada, “Colombian clays binary mixtures: Physical changes due to thermal treatments,” DYNA, vol. 87, no. 212, pp. 73–79, 2020, doi: 10.15446/dyna.v87n212.82285. [27]A. M. Rabie, E. A. Mohammed, y N. A. Negm, “Feasibility of modified bentonite as acidic heterogeneous catalyst in low temperature catalytic crackingprocess of biofuel production from nonedible vegetable oils,” J. Mol. Liq., vol. 254, no. 2018, pp. 260–266, 2018, doi: 10.1016/j.molliq.2018.01.110. [28]A. Kadeche et al., “Preparation, characterization and application of Fe-pillared bentonite to the removal of Coomassie blue dye from aqueous solutions,” Res. Chem. Intermed., vol. 46, no. 11, pp. 4985–5008, 2020, doi: 10.1007/s11164-020-04236-2. [29]C. I. R. De Oliveira, M. C. G. Rocha, A. L. N. DaSilva, y L. C. Bertolino, “Characterization of bentonite clays from Cubati, Paraíba Northeast of Brazil,” Ceramica, vol. 62, no. 363, pp. 272–277, 2016, doi:10.1590/0366-69132016623631970. [30]I. Z. Hager, Y. S. Rammah, H. A. Othman, E. M. Ibrahim, S. F. Hassan, y F. H. Sallam, “Nano-structured natural bentonite clay coated by polyvinyl alcohol polymer for gamma rays attenuation,” J. Theor. Appl. Phys., vol. 13, no. 2, pp. 141–153, 2019, doi: 10.1007/ s40094-019-0332-5. [31]A. Tebeje, Z. Worku, T. T. I. Nkambule, y J. Fito, “Adsorption of chemical oxygen demand from textile industrial wastewater through locally prepared bentonite adsorbent,” Int. J. Environ. Sci. Technol., no. 0123456789, 2021, doi: 10.1007/s13762-021-03230-4. [32]F. E. Özgüven, A. D. Pekdemir, M. Önal, e Y. Sarıkaya, “Characterization of a bentonite and its permanent aqueous suspension,” J. Turkish Chem. Soc.Sect. A Chem., vol. 7, no. 1, pp. 11–18, 2019, doi: 10.18596/jotcsa.535937. [33]S. Tao, S. Wei, e Y. Yulan, “Characterization of Expanded Graphite Microstructure and Fabrication of Composite Phase-Change Material for Energy Storage,” J. Mater. Civ. Eng., vol. 27, no. 4, p. 04014156, 2015, doi: 10.1061/(asce)mt.1943-5533.0001089. [34]M. Li, Z. Wu, H. Kao, y J. Tan, “Experimental investigation of preparation and thermal performances of paraffin/bentonite composite phase change material,” Energy Convers. Manag., vol. 52, no. 11, pp. 3275–3281, 2011, doi: 10.1016/j.enconman.2011.05.015. [35]S. M. Hosseini, E. Ghasemi, A. Fazlali, y D. E. Henneke, “The effect of nanoparticle concentration on the rheological properties of paraffin-based Co3O4 ferrofluids,” J. Nanoparticle Res., vol. 14, no. 7, 2012, doi: 10.1007/s11051-012-0858-9

Ecoductos Energeticos

ImagenesLa siguiente propuesta mostrara la importancia de la utilización de la energía cinética producida por el transporte de fluidos en ductos, para convertirla en energía eléctrica.Este proyecto beneficiara a las regiones en los cuales pasan las grandes, medianas y pequeñas redes de transporte de fluidos por ducto tales como: agua, gas natural, petróleo crudo y gasolina; las cuales tanto las empresas privadas, como la comunidad en que se ubican estas infraestructuras se beneficiaran, de la generación de energía eléctrica, donde la red suministradora de energía eléctrica no alcanza a llegarThe following proposal will show the importance of using the kinetic energy produced by the fluid transport in pipelines for energy eléctrica.Este project will benefit the regions which pass the large, medium and small fluid transport networks by product such as water, natural gas, crude oil and gasoline, which both private companies and the communities in which these facilities are located to benefit from the generation of electricity where the electricity supply network fails to ge

SNDR Limits of Oscillator-Based Sensor Readout Circuits.

This paper analyzes the influence of phase noise and distortion on the performance of oscillator-based sensor data acquisition systems. Circuit noise inherent to the oscillator circuit manifests as phase noise and limits the SNR. Moreover, oscillator nonlinearity generates distortion for large input signals. Phase noise analysis of oscillators is well known in the literature, but the relationship between phase noise and the SNR of an oscillator-based sensor is not straightforward. This paper proposes a model to estimate the influence of phase noise in the performance of an oscillator-based system by reflecting the phase noise to the oscillator input. The proposed model is based on periodic steady-state analysis tools to predict the SNR of the oscillator. The accuracy of this model has been validated by both simulation and experiment in a 130 nm CMOS prototype. We also propose a method to estimate the SNDR and the dynamic range of an oscillator-based readout circuit that improves by more than one order of magnitude the simulation time compared to standard time domain simulations. This speed up enables the optimization and verification of this kind of systems with iterative algorithms.This work has been funded by projects 610484 FP7-IAPP of the European Union and TEC2014-56879-R of CICYT, Spain. The authors would like to thank Roberto Nonis and Pedro Amaral from Infineon Technologies Austria AG for helpful discussions

Generador de un vórtice horizontal confinado

Since there is no theory for its dimensioning, in this paper, the design, construction and testing of a device that induces inside a horizontal axis vortex is described. The apparatus consists of a semi-convergent nozzle attached to a cylindrical vortex chamber with a side orifice and works horizontally submerged in a water flow with the intake nozzle forward. The coupling of these elements determines an incident tangential flow in the vortex chamber and causes it to develop a horizontal vortex. Thisvortex generator was tested on an experimental open channel without producing stagnation inside, despite being intrusive and with high form drag. The trials showed that the rotational velocity of the vortex increases in decreasing the radius and the axial distance to the drain orifice. Because of its ability to convert the initial translational movement of the flow into rotation, the vortex could be used to generate power. Other applications are not discarded though.Dado que no hay teoría para su dimensionamiento, en este trabajo sedescribe la concepción, construcción y prueba de un dispositivo queinduce en su interior un vórtice de eje horizontal. El aparato consta deuna tobera semiconvergente unida a una cámara de vórtice cilíndricacon orificio lateral y funciona sumergido horizontalmente en un flujode agua con la admisión de la tobera hacia adelante. El acople de estoselementos determina un flujo incidente tangencial en la cámara de vórticey hace que en ella se desarrolle un vórtice horizontal. Este generador devórtice se probó en un canal experimental de laboratorio sin producir ensu interior estancamiento, pese a ser intrusivo y con elevada resistenciade forma. Los ensayos mostraron que la velocidad de giro del vórticeaumenta al disminuir el radio y la distancia axial al orificio de desagüe.Por su capacidad para convertir en rotación el movimiento inicial detraslación del flujo podría servir para generar potencia, aunque no sedescartan otras aplicaciones

PERTINENCIA DE LOS PROYECTOS FINANCIADOS CON RECURSOS DEL S.G.R. QUE INCIDEN EN LOS INDICADORES DE CALIDAD DE VIDA DE LA POBLACIÓN EN LOS DEPARTAMENTOS DE HUILA Y CAQUETÁ

The current research article comes from the thesis Relevance of financed projects with S.G.R resources that have an impact on the population quality of life indicators in the departments of Huila and Caquetá, it is focused on the approval and disapproval of the financed projects with resources from the General System of Royalties (S.G.R) in the departments of Huila and Caquetá. The methodology used is applied non-experimental with a qualitative and quantitative approach, it was carried out through a mixed survey, to a sample of 450 beneficiaries of these projects, it added up to 45 projects in housing, health, education, utilities, agriculture and rural development sectors, 30 for Huila and 15 for Caquetá. The research proves the fact that any investment is likely to mistakes of any kind, however, the projects in the departments of Huila and Caquetá are characterized by having the lack of communication in common among involved people in the projects as a determining factor in the failure of some investments and changes in their execution..El presente artículo de investigación se deriva de la tesis Pertinencia de los proyectos financiados con recursos del S.G.R. que inciden en los indicadores de calidad de vida de la población en los departamentos de Huila y Caquetá, centrándose en las conformidades e inconformidades de los proyectos financiados con recursos del sistema general de regalías (S.G.R) en los departamentos de Huila y Caquetá. La metodología utilizada es aplicada no experimental con enfoque cualitativo y cuantitativo, desarrollada por medio de una encuesta mixta, a una muestra de 450 beneficiarios de estos proyectos, siendo un total de 45 proyectos en los sectores de vivienda, salud, educación, agua potable y saneamiento básico, y agricultura y desarrollo rural, para el Huila 30 y para el Caquetá 15. La investigación confirma el hecho de que cualquier inversión es susceptible de errores de cualquier tipo, no obstante, los proyectos de los departamentos del Huila y Caquetá se caracterizan por tener en común la falta de comunicación entre las partes interesadas de los proyectos como un factor determinante del fracaso de algunas inversiones y distorsiones en la ejecución de estas