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

[Objective] This article presents the results of research on the teaching and learning of the criterion “implement a representative sample of the complexity of the mathematical object to be taught,” which was carried out with high school mathematics teachers from Ecuador in a master’s degree program in continuing education. [Methodology] After a discussion of the instructional process which was used when teaching this criterion, a qualitative analysis of the responses to one of the tasks proposed for the students in this master’s degree program is presented: creating tasks for whose resolution the students had to apply a certain partial meaning of the Pythagorean theorem (geometric or arithmetic-algebraic), as a demonstration of the learning that they had achieved. [Results] The results show that some students in the master’s degree program proposed tasks to work on the Pythagorean theorem, but did not specify or justify whether the tasks they designed were related to arithmetic-algebraic meaning, to geometric meaning or to both; other students did not propose any task to work on arithmetic-algebraic meaning; and one participant in the master’s program did not propose any task to work on geometric meaning. It was also observed that some students created tasks that did not correspond to either of these meanings. [Conclusions] It was concluded that teachers have difficulties in creating a task and indicating the type of meaning of the Pythagorean theorem that should be used to solve it, and that geometric meaning was most related to the tasks that they proposed.

Possible surface manifestations of liquefaction were evaluated by means of severity indices, at a regional scale for the Jacó area, using information generated by 15 CPTu, estimating the seismic demand in a deterministic manner for 24 scenarios, for expected accelerations from ground motion prediction equations for Central America, considering crustal and subduction earthquakes, both intraplate and interplate. The results allow the identification of three areas where different levels of damage would be expected, depending on the seismic hazard represented in the analyzes by means of the magnitude of an earthquake and the accelerations that it could produce, and prioritize those to be investigated in greater detail for the development of private projects, public infrastructure and the location of essential buildings. The usefulness of the results is based on guiding municipal and emergency authorities to anticipate the response to the occurrence of an analysis scenario or another with intermediate conditions, knowing in advance the distribution of the sites where the damage could be greater in order to guide the immediate response and recovery efforts. It is expected that the results of this project, although preliminary, will serve as an input for the management of the risk associated with liquefaction through engineering and other measures, for purposes of land use planning and for the development of public policies for the district of Jacó, as could be a regulatory plan.

Solar energy is a type of renewable energy that, due to its nature, it is intrinsically influenced by the variability of meteorological and geographical conditions of the site. To tackle variability, storage technologies such as batteries can be used, they enable the integration of these energies into the electricity network and supply of loads at times of low generation. In this paper, a technical and economic analysis of a photovoltaic (PV) system including energy storage is carried out. Therefore, a model of a photovoltaic system with and without energy storage was developed in order to compare the technical and economic metrics for each case in the context of a residential system, while following a flat tariff. Based on the analysis, the results indicate that from the economic point of view, it is more profitable to install systems operating only with PV modules. On the other hand, the systems with pv system and storage allows a better use of the photovoltaic energy as can be seen from the metrics of self-consumption and autarky. Thus, this article contributes to the analysis of photovoltaic systems with energy storage through batteries, a relatively new technology in the country, collaborating with the generation of knowledge of systems that are expected to substantially change the electrical system.

This paper presents a research study about timber shear walls, with materials commercially available in Costa Rica. With new developments in engineered timber, the Costa Rican Seismic Code included a chapter on timber structures, defining diaphragms and shear walls as part of the lateral resisting system.  A research study was then carried out, with the objective of determining the structural behavior of a typical shear wall. Twelve specimens were constructed and tested, varying the nail spacing and anchorage system. The specimens were tested with monotonic and cyclic loading procedures according to ASTM E564 and ASTM E2126 respectively. It was found that the specimens can develop an adequate shear strength and stiffness if the end studs are adequately anchored to the foundation. These results are an important input for the Costa Rican Seismic Code and for the development of engineered timber in Costa Rica.

Field wave data are a relevant source of information with high impact for marine sciences and engineering. The present work compiled, in a single database, the different wave data records found in Costa Rica. Such wave data were compared with the WAVERYS reanalysis from the Copernicus Marine Environment Monitoring Service with the purpose of examining this information and its possible use in future research at both the country and regional levels. The historical wave data compilation considered records documented in different projects carried out on behalf of several governmental institutions. Statistical methods were used to analyze and compare, spatially and temporally, the information contained both in the field wave data and in the WAVERYS reanalysis. Results showed that, in the Caribbean, there are wave records between 2015 and 2017. In the Pacific, there are measurements made during the construction of Puerto Caldera between 1978 and 1985. There are also wave data obtained in different sites between 2009 to 2011 and by a recently established gauge network from 2014 onwards. It was verified that the reanalysis database has a high potential for applications in marine sciences and coastal engineering in this region of the Earth.

Costa Rica has a housing deficit for its most vulnerable population. There is a lack of information and evaluation of possible construction systems for social interest housing than can improve indicators like scope, cost, quality and construction time in the early phases of a project.An evaluation was conducted with technical and impartial criterion on nine (9) construction systems social housing, specifically for the activities of construction of foundations, walls and finishes, applying the Quality Function Deployment Matrix (QFD)The QFD Matrix transfers user requirements to production requirements using "What's" and "How's" [6]. The final ratings are based on a number of eight hundred ten (810) results based on the variables for two study actors (The contractor and the user).For the contractor, the prefabricated concrete system consisting of columns and horizontal panels, obtained the highest evaluation (236.5), was the system with the best rating.For the user, concrete masonry system, obtained the highest evaluation (196.3)The results are nor absolute, they vary on factors such as the market, regulations, social perception, among others.When a system obtains a better rating, it means that, for the variables considered, for its assigned importance and for the evaluated user,It means that it is the most adequate. It can´t be concluded that in absolute terms, a system with a higher rating is better than the others.

The purpose of this study is to evaluate the risks of a dock that is part of a ship tankers terminal; the evaluation considered the ISO-31000:2018 standard. In accordance with the object of study, the next phases were applied: scope, context, criteria and risk assessment. The following areas were identified: occupational health and safety, environment, natural phenomena and integrity of assets. For the identification phase, a combination of techniques was used, including on-site observation, brainstorming, and hazard identification (HAZID). Regarding the analysis, the simplified RE method was used and the Tolerability of Risk (ToR) model was employed for the assessment. The results determined the level for each of the risks, namely: fire, explosion, bodily harm, solid waste pollution, liquid waste pollution, tropical storms, corrosion, and damage to infrastructure and equipment.

In this work, the determination of the mechanical and photocatalytic properties of asphalt modified with Titanium Dioxide was proposed as an object of study through Marshall tests and rhodamine B degradation, the methodology was adapted to applied type research, experimental design and quantitative approach. , the study population included 24 specimens in total, 6 standard samples, 6 samples with 2% titanium dioxide, 6 with 4% titanium dioxide and 6 with 8% titanium dioxide. It was concluded that titanium dioxide is a good additive to improve its mechanical properties, with the addition of 2% presenting the best results, managing to improve all the mechanical properties of the asphalt mix compared to the standard mix. Regarding the photocatalytic degradation property, it was concluded that the mixture is capable of degrading the organic dye rhodamine B, showing the best results with the addition of 8% Tio2, for R4 with 8% titanium dioxide, a percentage of 11.76% and for R26 with 8% titanium dioxide, it yielded a degradation of 28.49.

Report of conferences of the IV Research Conference of the Faculty of Engineering of the year 2022.

ResumenEn noviembre de 1999 el esquiador de fondo de origen alemán Johann Muehlegg, consiguió su nacionalización española. Los triunfos deportivos no tardaron en llegar logrando la Copa del Mundo en el 2000, dos medallas en el Mundial de 2001 y tres medallas de oro en los Juegos Olímpicos de Salt Lake City en el 2002. El día después de conseguir su última victoria, el Comité Olímpico internacional (COI) le comunicó que había dado positivo por una sustancia denominada darbepoetina alfa y fue inmediatamente expulsado de la competición retirándole todas las medallas. A partir de ese momento el nuevo ídolo del deporte español pasó de héroe a villano en pocos días. Esta investigación tiene como objetivo principal analizar el tratamiento informativo que la prensa generalista y deportiva española ofreció del esquiador de fondo de origen alemán Johann Muehlegg, desde su irrupción en el panorama deportivo de este país hasta su descalificación por dopaje y su posterior retirada. Se examina la cobertura desarrollada por los periódicos El País, El Mundo, La Vanguardia, Mundo Deportivo y Marca, en el periodo cronológico comprendido entre noviembre del 1999 y diciembre del 2006. La prensa convirtió a Muellegg en el modelo perfecto de integración en la sociedad española y asimilación de las identidades nacionales, para posteriormente, una vez conocido su dopaje, transformarse en el peor ejemplo para el deporte español y condenarlo al olvido.  AbstractIn November 1999, the German cross-country skier Johann Muehlegg obtained his Spanish nationality. He won the World Cup in 2000, two medals at the 2001 World Cup and three gold medals at the Olympic Games in Salt Lake City in 2002. The day after his last victory, the International Olympic Committee (IOC) informed him that he had tested positive for a substance called darbepoetin alpha and he was immediately expelled from the competition and all his medals were withdrawn. From that moment on, the new idol of Spanish sport went from hero to villain in a few days. The main objective of this research is to analyze the informative treatment that the Spanish general and sports pressoffered to Johann Muehlegg, from his irruption in the sports scene of this country until his disqualification for doping and his subsequent withdrawal. It examines the coverage developed by the newspapers El País, El Mundo, La Vanguardia, Mundo Deportivo and Marca in the chronological period between November 1999 and December 2006. The press turned Muehlegg into the perfect model of integration into the Spanish society and assimilation of national identities, to later, once his doping was known, become the worst example for Spanish sport and condemn him to oblivion. This research has an approach of historical analysis, specifically from the history of the present, and with the use of a methodology based on content analysis.