Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Context: The concern for mitigating the environmental impact generated by the use of synthetic fibers as reinforcement of traditional composite materials has promoted the design and characterization of composites made from the combination of materials of plant origin. However, despite its multiple advantages, for its efficient use as construction materials it is necessary to deepen the determination of the effect of design parameters on its mechanical performance.   Method: The objective of this study is to determine the effect of the design parameters (type of fibers and surface treatment on the physical and mechanical properties of panels made with materials (fibers and resin) of plant origin. For the elaboration of the composite, two types of fibers were used: Arundo Dónax fibers and Guadua Angustifolia Kunth fibers. To produce the panels, the fibers were randomly distributed in a vegetable resin, obtained from the processing of castor oil. To evaluate the effect of the treatment on the properties of the composite three conditions were considered: fibers without treatment, fibers treated with sodium hydroxide solution and fibers treated with plasma. The density in anhydrous state, the effective absorption capacity, the surface absorption, the swelling percentage, the breaking modulus, and the apparent elastic modulus were determined experimentally. From the experimental results, an analysis of the response surface was carried out through the implementation of a central compound design, using a commercial software.   Results: From the experimental results an analysis of the response surface was carried out. Pareto diagrams and contour graphs were obtained for each of the properties studied. From the statistical results it was possible to establish equations that allow predicting the properties of the compound based on the type of fiber and the treatment applied to its surface.   Conclusions: From the results, it was possible to verify the effect of the type of fibers and their surface modification on the physical properties of compounds made with materials of plant origin. Other parameters such as orientation of the fibers, as well as variables associated with the processing conditions (pressure and compaction time) can influence the properties of the material) and will be evaluated in future works

Contexto: El problema de localización y ruteo constituye una de las principales temáticas en el área de logística e investigación de operaciones con un enfoque hacia la minimización de los costos totales del sistema. Sin embargo, en la gestión de la cadena de suministro, que actualmente presenta una tendencia hacia la sostenibilidad, la mayoría de las decisiones involucra la optimización simultánea de diversos objetivos, incluyendo perspectivas económicas, sociales y ambientales, de lo cual surge el problema de localización y ruteo con múltiples objetivos. Método: Se realiza una revisión sistemática de la literatura sobre el problema de localización y ruteo con múltiples objetivos, consultando las bases de datos Scopus y Web of Science. De acuerdo con unos criterios de selección específicos, se identifican 99 artículos científicos asociados a la temática durante el periodo comprendido entre 1989 y 2022, los cuales se clasifican según el tipo de aplicación. Resultados: Se describen las características más importantes para cada una de las aplicaciones del problema de localización y ruteo con múltiples objetivos en la literatura y se realiza una revisión de las investigaciones según sus objetivos de estudio y métodos de solución, para finalmente identificar las oportunidades de investigación principales. Conclusiones: En primer lugar, la mayoría de los estudios sobre el problema de localización y ruteo multiobjetivo han estudiado la gestión de residuos, la distribución de elementos de socorro, los productos perecederos, el problema de localización y ruteo verde, la cadena de frío y la distribución de bebidas. El objetivo de optimización de mayor implementación es la minimización de costos, combinado con otros objetivos: minimización de riesgos, impactos ambientales, minimización de tiempo, maximización de la satisfacción del cliente, balance de carga de trabajo y confiabilidad rutas. Por otra parte, se aplican métodos exactos y aproximados multiobjetivo para dar solución al problema, siendo los algoritmos evolutivos los más usados para modelos de mayor complejidad. Finalmente, las investigaciones actuales están orientadas al desarrollo de modelos bajo condiciones de incertidumbre y estocásticos, múltiples periodos, ventanas de tiempo, múltiples escalones y flota heterogénea.

Context:  Wind energy sources utilize renewable, free, and environmentally friendly resources, so there are projects focused on the design of wind turbines to increase their efficiency. Simulations using computational fluid dynamics techniques allow designs to be analyzed. which, are then validated through experimentation and wind tunnel measurements. Method: Data acquisition is performed by using Wind Sensor Rev.P sensors to measure wind velocity, and MMA7361 accelerometer to measure the vibrations generated by the wind in the turbine. Additionally, an ESP32 is required to process and transmit the data via Bluetooth, thus facilitating the installation of the real-time monitoring module inside the wind tunnel. Results: A monitoring module with a sampling rate of 5 ms was obtained, thus allowing real-time data acquisition, with a resolution of 12 bits for good data capturing accuracy and a transmission rate of approximately 74000 bps. An application capable of plotting 3D acceleration and 2D wind speed signals was also created. Conclusions: The device developed serves as a support for future wind turbine design projects since it is wireless, its installation is simple, it facilitates data collection inside a wind tunnel, and it allows visualizing the turbine’s behavior in real time by means of a graphic interface.

Context:  Off-grid photovoltaic systems are one of the main alternatives to fulfill the need for electricity in rural areas where the connection to traditional electrification systems is not possible. Among the components of a photovoltaic off-grid system, the charge controller must adapt the voltage and current levels to store the energy delivered by the panels in batteries. Method: In this work, a maximum power point tracking (MPPT) charge controller based on the Perturbation and Observation (P&O) technique was implemented and evaluated. Additionally, the state of charge of the battery was estimated by combining the ampere-hour counting method and the open-circuit voltage. The controller implements a two-phase charging algorithm for lead-acid batteries. Results: The developed charge controller obtained an average efficiency of 84,7% and reached a maximum value of 96,3%. In addition, the two-phase charging algorithm and the state of charge estimation method implemented in the controller allowed for the adequate control and monitoring of the battery charging and discharging processes. ConConclusions: The proposed charge controller follows the maximum power point of the solar panel and allows storing energy in lead-acid batteries while supervising their state of charge.

Context:  In engineering, modeling for risk analysis and ensuring the validity of results in systems that include computational routines requires the analysis of the sources and categories of uncertainty, which, in this context, can be classified as aleatoric and epistemic. Method: A literature review from databases such as Google Scholar, IEEEXplore, and ScienceDirect is presented herein, analyzing trends and approaches related to the concept of uncertainty within the framework of soft metrology, in order to improve our understanding when there are additional restrictions due to the assurance of the validity of the results. Results: This paper presents concepts and comparisons that aid in the understanding of epistemic and random uncertainty in soft metrology measurement processes and the way in which it is related to the assurance of the validity of results within the framework of learning machines. Conclusions: Representation quality in soft metrology systems is constantly influenced by random uncertainty, while epistemic uncertainty exhibits descending dynamics when the fit of the model improves with sufficient training data.

In the field of General Social Services there is a profound deficit of evaluative research to assess some relevant criteria. Likewise, it is necessary to improve the evaluation that feeds back the decision-making in social policies contexts. The article presents the results of an evaluation of the Home Care Service in rural Aragon, whose objective is to estimate the effectiveness, efficiency, coverage and satisfaction with this service. The research uses a mixed descriptive-explanatory method that combined quantitative techniques (statistical exploitation of Social Services information systems and the satisfaction survey) and qualitative techniques (interviews to experts and professionals). The instrument includes variables grouped around program effectiveness, relevance, efficiency, user satisfaction, intensity and targeting of users according to their degree of dependency. The study highlights the high level of user satisfaction, the improvement in their social and health situation and the recognition of the work of the home help assistants. The need to strengthen the work of the Home Care Service requires appropriate instruments for evaluation, especially in a rural context with a care deficit, with high levels of ageing and over-ageing of the population.

The creation in Spain of the Evaluation Agency (AEVAL) on 1-1-2007 was part of a reform program, which was intended to generate a process of innovation and modernization of public sector activity. Only 10 years later, after various vicissitudes, this entity disappeared. So far there has not been any rigorous analysis of the reasons that cause the dissolution of AEVAL and, what is even more important, no reflection has been made about the Agency’s experience and its influence. This article tries to fill that gap providing information and reflections to get to know this unique experience and some of the root causes of its difficulties and achievements, so as to be able to extract lessons for the institutional development of evaluation in Spain.

What impact have the two recent economic crises had on citizens’ public policy preferences? During the Great Recession government responses focused on the adoption of strict austerity measures while during the COVID-19 pandemic, which has brought economic activity to a halt, have been oriented towards an unprecedented increase in the budget to immediately address collective needs. These two contexts provide an ideal setting for research on changes in public opinion at critical junctures. In this regard, the article examines the evolution of Spaniards’ public policy preferences since the onset of the 2008 recession, focusing on the period of the pandemic. To this end, attitudes towards public spending in six essential areas are analyzed, based on survey data from 2005 to 2022. The results suggest that spending preferences change significantly in these situations, at least in the short term, and that society supports increased expenditures, although it establishes priorities among public policies. Moreover, these spending priorities are found to have shifted between the Great Recession and the health crisis. Finally, it has been found that there has been some polarization along class and ideological lines.

The new Spanish curriculum for Compulsory Secondary Education incorporates important changes with respect to previous curricula, following a competency-based education. This paper analyses the extent to which the new curriculum incorporates the recommendations of European institutions and other international bodies regarding the development of citizenship education and a European dimension of education. To this end, a content analysis of the new curriculum is carried out. The results show that the new curriculum is clearly aligned with these international recommendations and is committed to a competence-based education in which transversal contents in citizenship education play a significant role.

Public administrations need spaces for co-creation, design and experimentation different from the usual, very formalized and hierarchical, in which collaboration, empathy, communication and creativity encounter barriers and difficulties of different kinds. The most irrelevant thing is what we call these spaces, although lately the proliferation of innovation laboratories promoted by and in the public sector, with different configurations, according to the prevailing design centered on the user or citizen, or on the authorities or public professionals, is well known. The National Institute of Public Administration (INAP), currently under the Ministry of Finance and Public Function, has joined this search for new spaces for design in 2022, following the study “13 proposals for the reform of the State Administration”, produced and published in the INAP, with the creation of the Public Innovation Labotatory. The design of this laboratory can be peculiar considering its incardination in the INAP not as an organic unit, but as a transversal function to support with all its means and resources innovation projects promoted by public entrepreneurs (whatever their legal configuration), which intend to solve public problems and generate tangible and measurable results.