Ingeniería

Producción de plástico biodegradable a base de almidón de yuca mediante un proceso termomecánico

Resumen El presente trabajo pretende elaborar un polímero termoplástico a base de almidón (TPS) extraído de una variedad de yuca, mediante un procesamiento termomecánico en un mezclador interno de polímeros. Se examinaron preliminarmente tres formulaciones para establecer una formulación base y se escogió el alcohol polivinílico (PVOH) para reforzar el TPS. Asimismo, se realizó un estudio estadístico de las condiciones de procesamiento, las cuales se establecieron en una temperatura de 110 °C, una velocidad de 75 rpm (1,25 Hz) y un tiempo de mezcla de 6 min. Finalmente, mediante un ajuste de los porcentajes relativos de los componentes, se llegó a obtener un material con una resistencia en tensión de (15,4 ± 0,9) MPa y una elongación de (44 ± 11) %. Por medio de una prueba de envejecimiento, se observó que las propiedades del TPS se estabilizaron a los 15 días de su elaboración. Además, a través de un estudio de la biodegradabilidad, se observó una reducción en la masa del plástico del (98,5 ± 0,3) %, luego de 22 días de enterrado. Bajo condiciones controladas, el material presenta propiedades mecánicas adecuadas para ser usado en aplicaciones cotidianas; sin embargo, es necesario subsanar su sensibilidad a la humedad ambiental, ya que esta influye de manera importante en dichas propiedades mecánicas.

Abstract The present research aims to formulate a thermoplastic polymer based on starch (TPS) extracted from a cassava variety, through a thermomechanical processing in an internal mixer. Three formulations, guided by preliminary tests, were analyzed to choose a base formulation. Polyvinyl alcohol (PVOH) was chosen to reinforce TPS. Likewise, a statistical study of the processing conditions was carried out, from which the temperature was optimized at 110 °C, the rotor speed at 75 rpm (1,25 Hz), and the processing time at 6 min. Finally, through adjustment of the relative percentages of the components, a material with a tensile stress of (15,4 ± 0,9) MPa and a strain deformation of (44 ± 11) % was achieved. An aging test showed that properties of the TPS materials reached stabilization after 15 days of their formation. In the same way, a biodegradability test showed a reduction in the plastic mass of (98,5 ± 0,3) % after 22 days of being buried. Under controlled conditions, the material exhibits adequate mechanical properties for use in everyday applications; however, it is necessary to address its sensitivity to ambient humidity, as this significantly influences these mechanical properties.

A comprehensive analysis of cybersecurity infrastructure in academic Environments

Abstract This paper addresses a comprehensive analysis of cybersecurity systems in academic environments taking as a case study the domains: ''www.ups.edu.ec'', ''cas.ups.edu.ec'', ''virtual.ups.edu.ec'' y ''dspace.ups.edu.ec'', of the Salesian Polytechnic University, using specialized tools such as Kali Linux and Nessus. Through these technologies, critical aspects of the system's security are evaluated: its ability to resist attacks, how effective its defense mechanisms are, and its capacity to identify exploitable weak points. A novel methodology is applied to evaluate the security of the system, using emerging technologies and innovative techniques. During the research, several vulnerabilities were identified covering the four studied domains. These were classified using the CVSS (Common Vulnerability Scoring System) rating protocol, which allowed the most critical ones to be prioritized and addressed first. In addition, a scan of open ports was performed to recognize possible unauthorized access points. As part of the security testing, a simulation of an email phishing attack was carried out by cloning the Salesian University access website, in order to assess users' susceptibility to this threat. Domain security analysis revealed critical vulnerabilities, including an outdated version of PHP and possible remote code execution (CVSS 9.8-10) in ''virtual.ups.edu.ec''. SSL/TLS security issues were also detected, such as the use of weak ciphers and outdated versions of TLS (CVSS up to 7.5). In addition, medium risks related to lack of HSTS and vulnerabilities in PHP and jQuery were found, along with weaker SSH configurations of lesser impact (CVSS 2.6-3.7). These results show the need for security updates and improvements.

Resumen This paper addresses a comprehensive analysis of cybersecurity systems in academic environments taking as a case study the domains: ''www.ups.edu.ec'', ''cas.ups.edu.ec'', ''virtual.ups.edu.ec'' y ''dspace.ups.edu.ec'', of the Salesian Polytechnic University, using specialized tools such as Kali Linux and Nessus. Through these technologies, critical aspects of the system's security are evaluated: its ability to resist attacks, how effective its defense mechanisms are, and its capacity to identify exploitable weak points. A novel methodology is applied to evaluate the security of the system, using emerging technologies and innovative techniques. During the research, several vulnerabilities were identified covering the four studied domains. These were classified using the CVSS (Common Vulnerability Scoring System) rating protocol, which allowed the most critical ones to be prioritized and addressed first. In addition, a scan of open ports was performed to recognize possible unauthorized access points. As part of the security testing, a simulation of an email phishing attack was carried out by cloning the Salesian University access website, in order to assess users' susceptibility to this threat. Domain security analysis revealed critical vulnerabilities, including an outdated version of PHP and possible remote code execution (CVSS 9.8-10) in ''virtual.ups.edu.ec''. SSL/TLS security issues were also detected, such as the use of weak ciphers and outdated versions of TLS (CVSS up to 7.5). In addition, medium risks related to lack of HSTS and vulnerabilities in PHP and jQuery were found, along with weaker SSH configurations of lesser impact (CVSS 2.6-3.7). These results show the need for security updates and improvements.

Metodología BIB 6D como herramienta para evaluar confort térmico apliado a centros educativos costarricenses

Resumen La tecnología facilita la toma de decisiones en materia de diseño de infraestructura, en particular, para sopesar diferentes escenarios climáticos a los que puede estar expuesta una obra. Específicamente, el diseño y la construcción de infraestructura educativa en el país plantea retos relevantes en materia de sostenibilidad y confort. En esta investigación, se implementó la metodología BIM 6D para evaluar el confort térmico en tres planos tipo del MEP, en diferentes ubicaciones del país: Nicoya, Pavas y Limón. Se evaluó la pertinencia del uso BIM –análisis energético– para estimar el confort térmico en edificaciones, aplicado a los casos de estudio señalados, mediante programas de modelado 3D como SketchUp y la aplicación OpenStudio para el análisis 6D. Entre los principales resultados, sobresale que los planos tipo genéricos actuales no responden a las diferentes necesidades del estudiantado en las diversas zonas climáticas del país estudiadas, ni fueron concebidos tomando en cuenta las disimiles realidades de los entornos donde se van a construir. Se concluyó que la incorporación de cambios de materiales de techos y paredes mejora la situación de confort actual, lo cual demuestra la necesidad de rediseñar estos planos para lograr temperaturas confortables. Esta investigación destaca la importancia de la metodología BIM 6D en la planificación eficiente de espacios educativos; además, puede ser replicable en sus conclusiones y aplicarse a otros tipos de infraestructura pública de servicios donde deban albergarse personas.

Abstract Technology facilitates decision-making regarding infrastructure design, in particular, to weigh different climatic scenarios to which a work may be exposed. Specifically, the design and construction of educational infrastructure in the country present relevant challenges in terms of sustainability and comfort. In this research, the 6D BIM methodology was implemented to evaluate thermal comfort in three typical MEP plans across different locations in the country: Nicoya, Pavas, and Limón. The relevance of using BIM –energy analysis– to estimate thermal comfort in buildings, applied to the indicated case studies, was evaluated, using 3D modeling programs such as SketchUp and the OpenStudio application for 6D analysis. Among the main results, it was noted that the current generic type plans do not respond to the different needs of the student body in the different climatic zones studied in the country, nor were they conceived taking into account the diverse realities of the environments where they will be built. It was concluded that incorporating changes in ceiling and wall materials improves the current comfort conditions, demonstrating the need to redesign these plans in order to achieve comfortable temperatures. This research highlights the importance of the 6D BIM methodology in the efficient planning of educational spaces; in addition, its conclusions can be applied to other types of public service infrastructure where people must be housed.

Estudio del circuito de control para un potenciostato con una sola fuente de alimentación

Resumen En este artículo, se presenta un circuito electrónico de control que opera con una única fuente de alimentación, para un potenciostato de bajo costo controlado desde una computadora, a través de una placa Arduino UNO. Se deducen las ecuaciones que modelan el funcionamiento del circuito y que permiten establecer tanto el voltaje de celda como la velocidad de barrido, según los requerimientos de una prueba electroquímica. Además, se deducen ecuaciones que permiten calcular la corriente de celda, al igual que el rango de corrientes que pueden ser medidas con una adecuada exactitud. Luego, se realizan pruebas con el fin de evaluar la capacidad del sistema para establecer un voltaje de celda y una velocidad de barrido deseados, así como la exactitud del sistema al medir la corriente de celda. Los resultados muestran una dependencia entre el rango de voltajes de celda que se pueden generar y la resistencia entre los electrodos. Asimismo, la exactitud de la velocidad de barrido depende del retardo aplicado y de la cantidad de datos que se registren. Finalmente, el error en la medición de la corriente de celda depende de la magnitud de la misma y de la resistencia de retroalimentación que se utilice en el seguidor de corriente.

Abstract In this work, an electronic control circuit using a single power source is presented for its use as a low-cost potentiostat, which is operated from a computer by means of an Arduino UNO board. The equations describing the behaviour of the circuit are derived, and then used to set the voltage of the electrochemical cell, as well as the sweep rate for a particular electrochemical experiment. Additionally, a set of equations to measure the current flowing through the electrochemical cell is derived, and the range of currents that can be accurately measured is presented. Several experiments are conducted in order to evaluate the capacity of the system to set the voltage of the cell and the sweep rate. The accuracy of the current measurements is also assessed though these tests. The obtained results show an important dependency between the range of cell voltages that can be applied and the resistance measured between the electrodes of the potentiostat. Also, the accuracy of the sweep rate depends on the delay applied and the number of data being recorded. Finally, the error in the current measurement is associated with the magnitude of this current and the feedback resistance being used in the current follower.

Cambios en el uso de parques regionales: una mirada en la postpandemia COVID-19 costarricense

Resumen El COVID-19 cambió la realidad urbana de forma permanente. Las restricciones obligadas de movilidad y distancia social llevaron a la población a revalorar los espacios abiertos de esparcimiento. Esta investigación busca medir los cambios percibidos por la población en los patrones de uso de los parques urbanos metropolitanos de Costa Rica en la postpandemia de COVID-19. Esto desde el punto de vista de la movilidad, accesibilidad y frecuencia de visitación, con miras a evidenciar el aporte y la valoración de estos espacios por la ciudadanía costarricense. El abordaje corresponde a una metodología cuantitativa, en la cual se trabajó con conteos tipo aforo de las personas usuarias, encuestas directas y levantamientos detallados de infraestructura en campo, para el parque de la Sabana, el parque de la Paz y el parque del Este, todos ellos ubicados en la Gran Área Metropolitana de Costa Rica. Los resultados muestran una apreciación de los espacios y un aumento de la frecuencia de visitación. Además, se refleja cómo las personas están dispuestas a viajar más distancia o tiempo para poder acceder a las facilidades que tienen los parques y los valoran positivamente, pese a limitaciones en el mantenimiento de la planta física. Se concluye que la pandemia de COVID-19 sí repercutió en los patrones de uso, que las personas valoran más los espacios y que estos tienen una amplia zona geográfica de influencia, la cual en su mayoría sobrepasa los 2 km de distancia, siempre con predominio de las personas de los cantones huéspedes del parque.

Abstract COVID-19 changed the urban reality permanently. The compulsory restrictions on mobility and social distance led population to reevaluate open spaces for leisure. This research aims to measure changes in population's perceived usage patterns of metropolitan urban parks in Costa Rica after the COVID-19 pandemic in 2023, focusing on mobility, accessibility and visitation frequency aiming to highlight the contribution and appreciation of these spaces by the Costa Rican population. This study uses a quantitative methodology, involving headcounts of park users, direct surveys, and detailed infrastructure surveys in the field, for the parks of la Sabana, la Paz, and el Este, located in the Greater Metropolitan Area of Costa Rica. The results show an appreciation for these spaces and an increase in visitation frequency. Additionally, there is evidence that people are willing to travel greater distances or spend more time accessing the parks' facilities. Despite less-than-ideal maintenance and conditions, people still value them positively. It is concluded that the COVID-19 pandemic did affect usage patterns, that people value these spaces more, and that they have a broad geographic influence, mostly exceeding 2 km in distance, with a predominant presence of people from the hosting cantons of the park.

Funciones de desempeño de seguridad vial para secciones de control en Costa Rica

Resumen Los choques viales representan un alto costo social y económico para el país. Por esta razón, se estudia la Red Vial Nacional de Costa Rica para determinar aquellas secciones de control con potencial de mejora, utilizando funciones de desempeño de seguridad vial. El estudio se realiza aplicando el método de exceso de frecuencia de choques esperado, ajustado con Bayes empírico. La metodología se toma del Manual de Seguridad de Carreteras de la AASHTO. El análisis se aplica a todas las secciones de control con disponibilidad de datos requeridos para la investigación, por lo que se estudian 911 secciones de control de la Red Vial Nacional. Se realizaron los análisis para cuatro modelos de choques: totales, solo heridos leves, solo muertos o heridos graves y colisión con motocicleta. Se determinaron las secciones de control con exceso de frecuencia de choques esperado. Además, a partir de los estudios realizados, se determinó que la cantidad de accidentes se ve influenciada principalmente por tres variables: tipo de superficie, condición de señalización y ancho de superficie. Es recomendable que se generen planes para mejorar la seguridad vial en las secciones de control con mayor exceso de frecuencia de choques esperado, debido a que representan un mayor potencial de mejora en términos de seguridad vial. Por otro lado, se sugiere estudiar las secciones de control con menor exceso de frecuencia de choques esperado para conocer las condiciones que tienen estos sitios.

Abstract Road crashes represent a high social and economic cost for the country. For this reason, the Costa Rican National Road Network is studied to determine those control sections with potential for improvement using road safety performance functions. The study is performed by applying the method of expected excess frequency of crashes, adjusted with empirical Bayes. The methodology is taken from the AASHTO Highway Safety Manual. The analysis is applied to all control sections with availability of data required for the research, so 911 control sections of the National Road Network are studied. The analyses were performed for four crash models: total crashes, minor injuries only, fatalities or serious injuries only, and collisions with motorcycles. The control sections with excess frequency of expected crashes were determined. In addition, from the studies performed, it was determined that the number of crashes is mainly influenced by three variables: type of surface, sign condition, and surface width. It is advisable to generate plans to improve road safety in the control sections with the highest excess frequency of expected crashes, since they represent a greater potential for improvement in terms of road safety. On the other hand, it is recommended to study the control sections with lower excess frequency of expected crashes, in order to know the conditions that prevail at these sites. SIMBOLOGÍA O NOMENCLATURA AASHTO American Association of State Highway and Transportation Officials. COSEVI Consejo de Seguridad Vial. HSM Highway Safety Manual. LANAMME Laboratorio Nacional de Materiales y Modelos Estructurales. MOPT Ministerio de Obras Públicas y Transportes. RVN Red Vial Nacional. SIG Sistema de Información Geográfica. SNIT Sistema Nacional de Información Territorial. TPD Tránsito Promedio Diario. TPDA Tránsito Promedio Diario Anual.