Pub Date : 2022-08-29DOI: 10.17533/udea.redin.20220889
Víctor Hugo Mosquera Leyton, C. F. Rengifo-Rodas
Electrical bioimpedance (EBI) is a non-invasive technique for monitoring bladder volume. The EBI approaches global impedance (GI), impedance ratio method (IRM), and voltage change ratio (VCR) have been successfully applied to detect changes in the volume of objects with constant but unknown conductivity. In this work, simulated and in-vitro experiments are used to compare the performance of these methods with respect to a new approach proposed by some authors and called modified VCR (MVCR). Experimental results indicated that GI, VCR, and MVCR indices increase when the volume of the object under study increases. On the other hand, no direct or inverse relationship between IRM and volume was observed. The coefficient of variation, defined as the interquartile range divided by the median of a set of measurements, was lower for MVCR, which indicates that the proposed approach is less sensitive to measurement noise than the other three methods.
{"title":"A modified voltage changes ratio (MVCR) for in-vitro volume estimation","authors":"Víctor Hugo Mosquera Leyton, C. F. Rengifo-Rodas","doi":"10.17533/udea.redin.20220889","DOIUrl":"https://doi.org/10.17533/udea.redin.20220889","url":null,"abstract":"Electrical bioimpedance (EBI) is a non-invasive technique for monitoring bladder volume. The EBI approaches global impedance (GI), impedance ratio method (IRM), and voltage change ratio (VCR) have been successfully applied to detect changes in the volume of objects with constant but unknown conductivity. In this work, simulated and in-vitro experiments are used to compare the performance of these methods with respect to a new approach proposed by some authors and called modified VCR (MVCR). Experimental results indicated that GI, VCR, and MVCR indices increase when the volume of the object under study increases. On the other hand, no direct or inverse relationship between IRM and volume was observed. The coefficient of variation, defined as the interquartile range divided by the median of a set of measurements, was lower for MVCR, which indicates that the proposed approach is less sensitive to measurement noise than the other three methods.","PeriodicalId":42846,"journal":{"name":"Revista Facultad de Ingenieria, Universidad Pedagogica y Tecnologica de Colombia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90848332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-18DOI: 10.17533/udea.redin.20220888
F. J. Ramírez-Gil, Á. Delgado-Mejía, Esteban Foronda-Obando, L. Olmos-Villalba
The modeling of heat transfer phenomena in thermal systems has been extensively explored in industry and academia by using the finite element method (FEM) with commercial software. However, when the thermal problem introduces complexities in geometry and physics, the availability of licenses for high-performance computing could represent a limitation to achieving results in a reasonable time. Hence, finite element analysis (FEA) using open-source software (OSS) becomes a prominent candidate in this case. Therefore, multiple open-source tools are integrated into this work to solve the heat transfer equation, including conduction, convection, and radiation. Several geometrically complex heat sinks commonly used in the electronics industry are considered application examples. The performance of parallel computing is assessed in terms of processing time. The finite element solution engine is built by implementing the energy balance equations in their weak formulation in Firedrake, using its solver PETSc, the mesh generator GMSH and the post-processor Paraview, thus creating a fully OSS-based Python framework. Finally, the results are verified with commercial software for different case studies, and its potential to be extended to other fields of engineering is evident.
{"title":"Thermal finite element analysis of complex heat sinks using open source tools and high-performance computing","authors":"F. J. Ramírez-Gil, Á. Delgado-Mejía, Esteban Foronda-Obando, L. Olmos-Villalba","doi":"10.17533/udea.redin.20220888","DOIUrl":"https://doi.org/10.17533/udea.redin.20220888","url":null,"abstract":"The modeling of heat transfer phenomena in thermal systems has been extensively explored in industry and academia by using the finite element method (FEM) with commercial software. However, when the thermal problem introduces complexities in geometry and physics, the availability of licenses for high-performance computing could represent a limitation to achieving results in a reasonable time. Hence, finite element analysis (FEA) using open-source software (OSS) becomes a prominent candidate in this case. Therefore, multiple open-source tools are integrated into this work to solve the heat transfer equation, including conduction, convection, and radiation. Several geometrically complex heat sinks commonly used in the electronics industry are considered application examples. The performance of parallel computing is assessed in terms of processing time. The finite element solution engine is built by implementing the energy balance equations in their weak formulation in Firedrake, using its solver PETSc, the mesh generator GMSH and the post-processor Paraview, thus creating a fully OSS-based Python framework. Finally, the results are verified with commercial software for different case studies, and its potential to be extended to other fields of engineering is evident.","PeriodicalId":42846,"journal":{"name":"Revista Facultad de Ingenieria, Universidad Pedagogica y Tecnologica de Colombia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74181927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-08DOI: 10.19053/01211129.v31.n61.2022.14724
Juan Sebastián González-Sanabria, Fabián-Nicolás Ramos-Corredor, Germán Amezquita-Becerra
The rise of digital repositories has framed a significant advance in access to academic and scientific knowledge, increasing its impact due to greater reach and lower cost. However, these platforms are a new topic that initially did not have standards or models to carry out their implementation and operation, which is why there were inconsistencies between repositories on issues such as interoperability, digital preservation, among others. Due to the lack of standardization and the exponential increase in the number of repositories, different organizations and researchers made multiple proposals to standardize the processes and characteristics of these platforms. The proposals materialized in models, such as the Dublin Core and DataCite metadata schemes, and in guides for the evaluation and implementation of repositories, such as the "Guide for the evaluation of institutional research repositories" by RECOLECTA or the DINI certificate (Deutsche Initiative für Netzwerk Information). The latter aim to evaluate the platforms in their entirety, including 8 sections with a total of 87 elements. Therefore, in this research an application was developed to automate the evaluation of repositories, automating processes that improve educational work using computer tools and their integration.
{"title":"Automation Tool for Institutional Repositories Evaluation","authors":"Juan Sebastián González-Sanabria, Fabián-Nicolás Ramos-Corredor, Germán Amezquita-Becerra","doi":"10.19053/01211129.v31.n61.2022.14724","DOIUrl":"https://doi.org/10.19053/01211129.v31.n61.2022.14724","url":null,"abstract":"The rise of digital repositories has framed a significant advance in access to academic and scientific knowledge, increasing its impact due to greater reach and lower cost. However, these platforms are a new topic that initially did not have standards or models to carry out their implementation and operation, which is why there were inconsistencies between repositories on issues such as interoperability, digital preservation, among others. Due to the lack of standardization and the exponential increase in the number of repositories, different organizations and researchers made multiple proposals to standardize the processes and characteristics of these platforms. The proposals materialized in models, such as the Dublin Core and DataCite metadata schemes, and in guides for the evaluation and implementation of repositories, such as the \"Guide for the evaluation of institutional research repositories\" by RECOLECTA or the DINI certificate (Deutsche Initiative für Netzwerk Information). The latter aim to evaluate the platforms in their entirety, including 8 sections with a total of 87 elements. Therefore, in this research an application was developed to automate the evaluation of repositories, automating processes that improve educational work using computer tools and their integration.","PeriodicalId":42846,"journal":{"name":"Revista Facultad de Ingenieria, Universidad Pedagogica y Tecnologica de Colombia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46555269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-08DOI: 10.17533/udea.redin.20220887
Americo Vicente Teixeira-Leite
Interest in very small-scale hydropower generation has increased over the past few years. These pico-hydro systems range from a few watts to several kW. The exploitation of low head sites does not require expensive civil works and is environmentally sustainable. Pico-hydro systems are attractive not only for remote areas where the grid is not available, but also for grid connection. This is especially relevant in existing infrastructures, used for other activities but which can also be used for energy generation. Waterwheels are emerging with enormous potential in this context. Low speeds and variations in head and water flow are a constraint to their connection to the grid. This study shows that they can be effectively connected to the grid using competitive and widely available technology for other renewable sources, such as photovoltaics. This paper presents an innovative approach for an effective grid connection of a pico-hydro system based on an overshot waterwheel. For this purpose, a permanent magnet synchronous generator and a photovoltaic inverter are used. The compatibility between them is analysed in detail and the analysis is valid for other hydro turbines. The 2 m diameter waterwheel has been installed on an existing infrastructure of an aquaculture centre. With a flow rate of about 13 l/s, it injects an average power of 126 W into a microgrid with a global efficiency of 50%.
{"title":"Effective grid connection approach for an overshot waterwheel","authors":"Americo Vicente Teixeira-Leite","doi":"10.17533/udea.redin.20220887","DOIUrl":"https://doi.org/10.17533/udea.redin.20220887","url":null,"abstract":"Interest in very small-scale hydropower generation has increased over the past few years. These pico-hydro systems range from a few watts to several kW. The exploitation of low head sites does not require expensive civil works and is environmentally sustainable. Pico-hydro systems are attractive not only for remote areas where the grid is not available, but also for grid connection. This is especially relevant in existing infrastructures, used for other activities but which can also be used for energy generation. Waterwheels are emerging with enormous potential in this context. Low speeds and variations in head and water flow are a constraint to their connection to the grid. This study shows that they can be effectively connected to the grid using competitive and widely available technology for other renewable sources, such as photovoltaics. This paper presents an innovative approach for an effective grid connection of a pico-hydro system based on an overshot waterwheel. For this purpose, a permanent magnet synchronous generator and a photovoltaic inverter are used. The compatibility between them is analysed in detail and the analysis is valid for other hydro turbines. The 2 m diameter waterwheel has been installed on an existing infrastructure of an aquaculture centre. With a flow rate of about 13 l/s, it injects an average power of 126 W into a microgrid with a global efficiency of 50%.","PeriodicalId":42846,"journal":{"name":"Revista Facultad de Ingenieria, Universidad Pedagogica y Tecnologica de Colombia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84608455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-05DOI: 10.19053/01211129.v31.n61.2022.13869
A. Paredes-Rodríguez, Andrés-Felipe Grisales-Aguirre, David-Alberto Sánchez-Zambrano
En la actualidad, las cadenas de suministro buscan establecer estrategias para la recuperación y reincorporación de los productos que cumplen su vida útil, no obstante en estas operaciones de logística inversa se presentan eventos que pueden generar no solamente pérdidas financieras para la empresa, sino también efectos nocivos sobre el medio ambiente y la comunidad. En este documento se realiza un proceso de identificación, priorización y control para los riesgos operacionales más representativos en el proceso de logística inversa del aceite vehicular usado debido al alto volumen de este residuo que se genera dentro del país y cuya mala gestión de las actividades de recuperación puede generar problemas ambientales, económicos y sociales. La metodología utilizada para el proceso de gestión de riesgo implica el uso de la herramienta multicriterio QFD Fuzzy, para evaluar los eventos operacionales más comunes dentro del proceso usando la valoración de expertos en el sector, y posteriormente se diseña una serie de estrategias de mitigación a través del uso del diagrama Ishikawa. Entre los resultados más relevantes encontrados en el estudio se tiene el hecho de que los riesgos más relevantes en la logística inversa del aceite vehicular usado son el inadecuado proceso de almacenamiento, la ausencia de un vehículo adecuado para el transporte y la baja calidad del residuo. La investigación realizada establece un marco de referencia para el proceso de gestión del riesgo en compañías que se dediquen al aprovechamiento y reutilización de productos en una cadena de suministro de ciclo cerrado.
{"title":"Gestión de riesgos operacionales en el proceso de logística inversa del aceite vehicular usado","authors":"A. Paredes-Rodríguez, Andrés-Felipe Grisales-Aguirre, David-Alberto Sánchez-Zambrano","doi":"10.19053/01211129.v31.n61.2022.13869","DOIUrl":"https://doi.org/10.19053/01211129.v31.n61.2022.13869","url":null,"abstract":"En la actualidad, las cadenas de suministro buscan establecer estrategias para la recuperación y reincorporación de los productos que cumplen su vida útil, no obstante en estas operaciones de logística inversa se presentan eventos que pueden generar no solamente pérdidas financieras para la empresa, sino también efectos nocivos sobre el medio ambiente y la comunidad. En este documento se realiza un proceso de identificación, priorización y control para los riesgos operacionales más representativos en el proceso de logística inversa del aceite vehicular usado debido al alto volumen de este residuo que se genera dentro del país y cuya mala gestión de las actividades de recuperación puede generar problemas ambientales, económicos y sociales. La metodología utilizada para el proceso de gestión de riesgo implica el uso de la herramienta multicriterio QFD Fuzzy, para evaluar los eventos operacionales más comunes dentro del proceso usando la valoración de expertos en el sector, y posteriormente se diseña una serie de estrategias de mitigación a través del uso del diagrama Ishikawa. Entre los resultados más relevantes encontrados en el estudio se tiene el hecho de que los riesgos más relevantes en la logística inversa del aceite vehicular usado son el inadecuado proceso de almacenamiento, la ausencia de un vehículo adecuado para el transporte y la baja calidad del residuo. La investigación realizada establece un marco de referencia para el proceso de gestión del riesgo en compañías que se dediquen al aprovechamiento y reutilización de productos en una cadena de suministro de ciclo cerrado.","PeriodicalId":42846,"journal":{"name":"Revista Facultad de Ingenieria, Universidad Pedagogica y Tecnologica de Colombia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48317541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-18DOI: 10.17533/udea.redin.20220785
Jhon Sebastián Hernández-Niño, Julie Joseane Murcia-Mesa, Hugo Alfonso Rojas-Sarmiento, M. Hidalgo, J. A. Navío-Santos
In this study, ZnO/TiO2 and ZnO/Nb2O5 photocatalysts were evaluated in the river pollution remediation and wastewater treatment from textile factories, thus, the target pollutants selected for this study were enteropathogenic bacteria and commercial dyes. The mixed oxide systems were extensively analyzed in order to explore their physicochemical properties. From this analysis, it was found that the coupling of two oxides did not modify the crystallinity of the pristine semiconductors. As a result, XRD Wurtzite phase, hexagonal phase, and anatase phases were identified for ZnO, Nb2O5, and TiO2 photocatalyst, respectively. Using UV-Vis DRS, a higher absorption for mixed oxides in the visible region of the electromagnetic spectrum was observed, along with a decrease in the band gap value in these materials. The results of the photocatalytic activity evaluation showed that the coupling of ZnO with Nb2O5 and TiO2 increased the effectiveness of the total organic carbon (TOC) and E. Coli elimination. 83% of TOC and elimination of 64% of E. coli were achieved using ZnO/Nb2O5 photocatalyst for the treatment of water samples from the polluted river.
{"title":"ZNO/TIO2 and ZNO/NB2O5 as effective systems for the treatment of enteric bacteria and commercial dyes","authors":"Jhon Sebastián Hernández-Niño, Julie Joseane Murcia-Mesa, Hugo Alfonso Rojas-Sarmiento, M. Hidalgo, J. A. Navío-Santos","doi":"10.17533/udea.redin.20220785","DOIUrl":"https://doi.org/10.17533/udea.redin.20220785","url":null,"abstract":"In this study, ZnO/TiO2 and ZnO/Nb2O5 photocatalysts were evaluated in the river pollution remediation and wastewater treatment from textile factories, thus, the target pollutants selected for this study were enteropathogenic bacteria and commercial dyes. The mixed oxide systems were extensively analyzed in order to explore their physicochemical properties. From this analysis, it was found that the coupling of two oxides did not modify the crystallinity of the pristine semiconductors. As a result, XRD Wurtzite phase, hexagonal phase, and anatase phases were identified for ZnO, Nb2O5, and TiO2 photocatalyst, respectively. Using UV-Vis DRS, a higher absorption for mixed oxides in the visible region of the electromagnetic spectrum was observed, along with a decrease in the band gap value in these materials. The results of the photocatalytic activity evaluation showed that the coupling of ZnO with Nb2O5 and TiO2 increased the effectiveness of the total organic carbon (TOC) and E. Coli elimination. 83% of TOC and elimination of 64% of E. coli were achieved using ZnO/Nb2O5 photocatalyst for the treatment of water samples from the polluted river.","PeriodicalId":42846,"journal":{"name":"Revista Facultad de Ingenieria, Universidad Pedagogica y Tecnologica de Colombia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84394710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-18DOI: 10.17533/udea.redin.20220786
Cristina Alejandra Domínguez-Cabrera, Juan Diego Febres-Eguiguren, Steven N. Cuadra
The main focus of this study was to investigate self-reported road traffic crashes (RTC) among drivers from Loja Ecuador and to illustrate the applicability of multiple correspondence analysis (MCA) in detecting and representing typologies of individuals who have experienced an RTC as well as the typology of RTC events, upon information collected through a web-based survey carried in 2021. Overall, 754 drivers were investigated and we estimated a life prevalence (LP) of RTC of 41.5% (95% CI 36.9 to 46.2). Typology of drivers who reported involvement in an RTC is characterized by a predominance of people of 25 to 40 years of age, who drive mainly cars and frequently experience distraction and use of a mobile phone when driving. Additionally, MCA indicated two distinctive typologies of RTC events. One is characterized by collision vehicle-to-vehicle, due to behavioral factors, occurring at low-speed limit roads during the afternoon. The second one is characterized by collision vehicle-to-surrounding occurring at medium-speed limit roads during the evening and late evening. Our study revealed major determinants of RTC are modifiable behavioral factors and that MCA is both a valid exploratory tool to identify individual and event typologies of those under at most risk to suffer an RTC and a feasible technique to be implemented in low-income countries such as Ecuador.
本研究的主要重点是调查来自厄瓜多尔洛哈的司机中自我报告的道路交通事故(RTC)，并说明多重对应分析(MCA)在检测和表示经历过RTC的个人类型以及RTC事件类型方面的适用性，这些信息是通过2021年进行的基于网络的调查收集的。总的来说，754名司机被调查，我们估计RTC的生命患病率(LP)为41.5% (95% CI 36.9至46.2)。报告参与RTC的司机类型的特点是，年龄在25至40岁之间的人占主导地位，他们主要驾驶汽车，在驾驶时经常分心和使用手机。此外，MCA显示了RTC事件的两种不同类型。一种是由于行为因素，车辆与车辆之间的碰撞，发生在下午的低速限制道路上。第二种是中速限制道路傍晚和深夜发生的车辆与周围环境的碰撞。我们的研究表明，RTC的主要决定因素是可改变的行为因素，MCA既是一种有效的探索性工具，可以识别最容易遭受RTC的个体和事件类型，也是一种可行的技术，可以在厄瓜多尔等低收入国家实施。
{"title":"Uncovering road traffic crashes typologies using multiple correspondence analysis (MCA), in a low-resource setting","authors":"Cristina Alejandra Domínguez-Cabrera, Juan Diego Febres-Eguiguren, Steven N. Cuadra","doi":"10.17533/udea.redin.20220786","DOIUrl":"https://doi.org/10.17533/udea.redin.20220786","url":null,"abstract":"The main focus of this study was to investigate self-reported road traffic crashes (RTC) among drivers from Loja Ecuador and to illustrate the applicability of multiple correspondence analysis (MCA) in detecting and representing typologies of individuals who have experienced an RTC as well as the typology of RTC events, upon information collected through a web-based survey carried in 2021. Overall, 754 drivers were investigated and we estimated a life prevalence (LP) of RTC of 41.5% (95% CI 36.9 to 46.2). Typology of drivers who reported involvement in an RTC is characterized by a predominance of people of 25 to 40 years of age, who drive mainly cars and frequently experience distraction and use of a mobile phone when driving. Additionally, MCA indicated two distinctive typologies of RTC events. One is characterized by collision vehicle-to-vehicle, due to behavioral factors, occurring at low-speed limit roads during the afternoon. The second one is characterized by collision vehicle-to-surrounding occurring at medium-speed limit roads during the evening and late evening. Our study revealed major determinants of RTC are modifiable behavioral factors and that MCA is both a valid exploratory tool to identify individual and event typologies of those under at most risk to suffer an RTC and a feasible technique to be implemented in low-income countries such as Ecuador.","PeriodicalId":42846,"journal":{"name":"Revista Facultad de Ingenieria, Universidad Pedagogica y Tecnologica de Colombia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80384922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-05DOI: 10.17533/udea.redin.20220783
I. D. Patiño-Arcila
Some fibrous reinforcements used in the manufacturing of parts by Liquid Composite Molding (LCM) have a dual-scale nature, which supposes flow imbalances between the tows and channels at mesoscopic scale, which in turn, cause uncontrolled defects (voids, dry points, among others) and could considerably affect the global flow behavior during the filling of cavities at macroscopic scale. In the present work, a new approach to conduct filling simulations of dual-scale fibrous reinforcements at mesoscopic scale is proposed. This consists of prescribing a pressure gradient along the Representative Unitary Cell, and imposing Stokes-Darcy matching conditions between the tows and the channel sub-domains to determine the filling of the former ones. Contrarily to the traditional approach, where a uniform pressure is assumed for the channels and only the porous media fluid is modeled, the present one allows considering the fluid pressure gradient at channels (fluid motion), air compressibility and dissolution, flow-direction dependent capillary pressure, and vacuum pressure, as well as capturing several phenomena involved in the dynamic evolution of intra-tow voids, namely, compression, mobilization at constant volume and migration from tows towards channel. The velocity vectors and streamlines in the tows and channel subdomains, when these phenomena take place, are analyzed as well.
{"title":"New approach for filling simulations of dual-scale preforms used in the manufacturing of composites materials.","authors":"I. D. Patiño-Arcila","doi":"10.17533/udea.redin.20220783","DOIUrl":"https://doi.org/10.17533/udea.redin.20220783","url":null,"abstract":"Some fibrous reinforcements used in the manufacturing of parts by Liquid Composite Molding (LCM) have a dual-scale nature, which supposes flow imbalances between the tows and channels at mesoscopic scale, which in turn, cause uncontrolled defects (voids, dry points, among others) and could considerably affect the global flow behavior during the filling of cavities at macroscopic scale. In the present work, a new approach to conduct filling simulations of dual-scale fibrous reinforcements at mesoscopic scale is proposed. This consists of prescribing a pressure gradient along the Representative Unitary Cell, and imposing Stokes-Darcy matching conditions between the tows and the channel sub-domains to determine the filling of the former ones. Contrarily to the traditional approach, where a uniform pressure is assumed for the channels and only the porous media fluid is modeled, the present one allows considering the fluid pressure gradient at channels (fluid motion), air compressibility and dissolution, flow-direction dependent capillary pressure, and vacuum pressure, as well as capturing several phenomena involved in the dynamic evolution of intra-tow voids, namely, compression, mobilization at constant volume and migration from tows towards channel. The velocity vectors and streamlines in the tows and channel subdomains, when these phenomena take place, are analyzed as well.","PeriodicalId":42846,"journal":{"name":"Revista Facultad de Ingenieria, Universidad Pedagogica y Tecnologica de Colombia","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90619849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-30DOI: 10.17533/udea.redin.20220682
Alejandro Casallas, Tatiana Córdoba, Leidy Sánchez-Cárdenas, M. Guevara-Luna, L. Belalcázar
Already published studies found that 20% of the atmospheric pollution variations are linked to local meteorology. This relationship may be more important in places with dense populations such as Latin American cities since the topography and fast multiscale changes are part of the tropical climate. Even so, this possibility has not been addressed in previous studies. This research aims to characterize the relationship between tropical climate variables and PM2.5 levels during high pollution events. The relationship between wind field, Turbulent Kinetic Energy (TKE), radiation, temperature, relative humidity, boundary layer height, and atmospheric stability with PM2.5 concentration was investigated. Statistical correlations and the parcel method were used to analyze the relationship between vertical motions and PM2.5. Obtained results show that the stability, vertical velocity, and boundary layer height do not significantly affect pollution levels. We identified some signals that are strongly related to PM2.5 high concentrations: weaker than average horizontal wind speed and TKE throughout the day, easterly winds in the morning (associated with the transport of ashes from wildfires produced on the Eastern plains), combined with a higher than average radiation peak. These results lead to a better understanding of the PM2.5 variations, which can be applied for the improvement of air quality models and have the potential to be part of a novel policy to manage air quality risk.
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Pub Date : 2022-06-30DOI: 10.19053/01211129.v31.n60.2022.14188
Yasmany Damián García-Ramírez
En la actualidad, el desarrollo y acceso tecnológico está llevando a cambiar diversos hábitos en población, como, por ejemplo, la forma en cómo se consume la información. Es así, que el uso de videos cortos e imágenes se usan los periódicos, redes sociales hasta alcanzar a la educación universitaria. Esta imagen o internet-meme ha sido usado en varias áreas del conocimiento para mejorar el aprendizaje de sus estudiantes, pero no en el diseño de carreteras, cuyo contenido se suele mantener las clases de forma tradicional. Por lo tanto, este estudio tiene por objetivo presentar una actividad académica que utiliza internet-memes para analizar un tema semanal antes de las clases virtuales síncrona. Para ello, participaron cuatro grupos de estudiantes de la materia de diseño geométrico de carreteras. Ellos debían revisar el contenido antes de la clase y elaborar un internet-meme, que era revisado por pares. Como resultado, los internet-memes pueden ser utilizados para controlar que el estudiante revise el material académico (videos, artículos, etc.), antes de asistir a la clave virtual, incluso se podría utilizar antes de una clase presencial. Los estudiantes estuvieron de acuerdo con el uso de los internet-memes, y en menor proporción con la revisión por pares. A pesar de esta última tendencia, la elaboración en combinación con la revisión por pares aumenta la posibilidad de que estudiante comprenda verdaderamente el tema. Por otro lado, los grupos dieron una valoración promedio del curso de al menos 8,86/10. Los estudiantes fueron conscientes del autoaprendizaje, quienes dieron una calificación promedio de al menos 7,74/10. Este artículo describe la experiencia de los estudiantes con el uso de los internet-memes, evaluando sus pros y contras de su uso.
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