Impact of Design Parameters on the Ratio of Compressive to Split Tensile Strength of Self-Compacting Concrete with Recycled Aggregate

[EN] Most concrete studies are concentrated on mechanical properties especially strength properties either directly or indirectly (fresh and durability properties). Hence, the ratio of split tensile strength to compressive strength plays a vital role in defining the concrete properties. In this review, the impact of design parameters on the strength ratio of various grades of Self-Compacting Concrete (SCC) with recycled aggregate is assessed. The design parameters considered for the study are Water to Cement (W/C) ratio, Water to Binder (W/B) ratio, Total Aggregates to Cement (TA/C) ratio, Fine Aggregate to Coarse Aggregate (FA/CA) ratio, Water to Solid (W/S) ratio in percentage, superplasticizer (SP) content (kg/cu.m), replacement percentage of recycled coarse aggregates (RCA), replacement percentage of recycled fine aggregates (RFA), fresh density and loading area of the specimen. It is observed that the strength ratio of SCC with recycled aggregates is affected by design parameters.S

Satisfaction Level of Engineering Students in Face-to-Face and Online Modalities under COVID-19—Case: School of Engineering of the University of León, Spain

[EN] University education in times of COVID-19 was forced to seek alternative teaching/learning methods to the traditional ones, having to abruptly migrate to the online modality, changes that have repercussions on student satisfaction. That is why this study aims to compare the level of student satisfaction in face-to-face and “forced” online modalities under COVID-19. A quantitative, cross-sectional methodology was applied to two groups of students: Under a face-to-face modality (n = 116) and under an online modality (n = 120), to which a questionnaire was applied under a Likert scale, with four dimensions: Course design structure, content, resources, and instructor. Non-parametric statistics, specifically the Mann–Whitney U-test, were used to compare the groups. The results showed that there are significant differences in the level of satisfaction of students in the face-to-face and online “forced” modalities (p = 0.01984 < 0.05), and the dimensions of the level of satisfaction that presented significant differences were course design structure (p = 0.04523 < 0.05) and content (p = 0.00841 < 0.05). The research shows that students in the face-to-face modality express a higher level of satisfaction, which is reflected in the dimension design structure of the course, specifically in its workload indicator, as well as in the dimension content, in its indicators, overlapping with other courses and materials.S

Resultados de una encuesta realizada como parte del plan de acción de León: la percepción ciudadana

ISSN Digital: 2340-7441[ES] La Directiva Europea sobre ruido ambiental, establece un enfoque común para evitar o reducir los efectos nocivos de la exposición al ruido. Para analizar la molestia debida a la contaminación acústica en León, se llevó a cabo un estudio mediante una encuesta entre 509 habitantes. En el estudio, las personas más sensibles al ruido también lo consideran un agente muy contaminante. Se constata que el ruido afecta a diversas actividades, como las interferencias en la comunicación y la actividad intelectual. Asimismo, se presentan las acciones consideradas más eficaces por los habitantes, para mitigar el ruido en su ciudad.[EN] The Environmental Noise Directive establishes a common approach to prevent or reduce the harmful effects of noise exposure. To analyze the nuisance due to noise pollution in Leon (Spain), we carried out a study using a survey of 509 people. It shows that people who consider them self as most sensitive to noise, also think about it as a highly polluting agent. Also, some daytime activities are affected, like interference with talks and intellectual activity. It also presents an overview of the actions considered more effective by the inhabitants to mitigate the noise in their cit

Estudio acústico de las zonas peatonales

ISSN: 2340-7441 (Versión Digital)[ES] En ocasiones, la transformación de espacios urbanos en productos de consumo turístico, no ha tenido en cuenta la protección medioambiental y la funcionalidad. Muchas de estas áreas se han convertido en zonas peatonales, donde numerosas fuentes de ruido pueden causar molestia entre la población, conduciendo al abandono de las mismas. Los mapas estratégicos de ruido evalúan globalmente la exposición al mismo, dejando dichas zonas al margen del estudio. En este sentido, se propone el análisis de la zona peatonal de León (España). Su incorporación a los mapas se realizará a partir de una clasificación urbana y medidas de corta duración.[EN] Sometimes, transformation of urban spaces in tourism consumption products, has not taken into account environmental protection and urban functionality. Many of these areas have been pedestrianized, where noise sources can cause annoyance, leading to their abandonment. Strategic noise maps assess global exposure to noise, however, this areas are outside of the maps. In this sense, we propose the study of the pedestrian area of the city of León (Spain). His addition to noise maps will be from an urban classification and short-term measures

Metodología para la medida y análisis vibracional in situ de compresores frigoríficos semiherméticos alternativos, mediante el empleo de algoritmos de clasificación automática = A methodology for the in situ measurement and analysis of vibrations in semihemetic reciprocating compressors by means of automatic classification algorithms

329 p.Este trabajo presenta una metodología basada en el empleo de algoritmos de clasificación automática para obtener patrones vibracionales como descriptores del comportamiento en régimen permanente de compresores frigoríficos semiherméticos alternativos. En primer lugar define la técnica adecuada para elegir los elementos de la cadena de medida, así como el sistema de sujeción del transductor, su posición y las direcciones en que se han de colocar sus ejes. Los resultados de aplicar esta técnica en un total de cien compresores, distribuidos en quince salas de máquinas, se utilizaron para alimentar a un sistema de clasificación automática. El sistema identificó cinco firmas espectrales que se diferencian en cuál de los dos primeros armónicos tiene mayor amplitud, en la amplitud de ese armónico, y en la presencia de armónicos significativos entre 400 y 600 Hz. Se ha observado que el comportamiento vibracional de los compresores es independiente de la sala de máquinas en que se encuentren ubicados, mientras que compresores de un mismo fabricante con igual número de cilindros tienden a presentar el mismo patrón vibraciona

Innovación en docencia de mineralogía a partir de la realización de vídeos sobre contenidos prácticos

En la página web http://laboratorio.wesped.es/, se muestran vídeos de ensayos de propiedades físicas de minerales, realizados por alumnos como una práctica de la asignatura “Mineralogía y Petrografía” (Grado en Ingeniería Minera), en el marco de un proyecto de innovación docente. Los minerales utilizados en la experiencia pertenecen a la Colección Geológica de la Universidad de León, formada por más de 2000 ejemplares. La experiencia fue evaluada por dos vías: a) comparación de los resultados académicos de los alumnos en esta práctica con resultados equivalentes de cursos académicos anteriores y, b) realización de una encuesta de satisfacción. La evaluación de la experiencia, aunque muy satisfactoria, no es concluyente, dado el reducido número de alumnos participantes. Por ello, esta experiencia se prolongará en el tiempo y se ampliará a otras asignaturas de los Grados de Ingeniería Minera y de la Energía. ostrar diversos conceptos de integración y adaptación fisiológica

Innovación en docencia de mineralogía a partir de la realización de vídeos sobre contenidos prácticos

En la página web http://laboratorio.wesped.es/, se muestran vídeos de ensayos de propiedades físicas de minerales, realizados por alumnos como una práctica de la asignatura “Mineralogía y Petrografía” (Grado en Ingeniería Minera), en el marco de un proyecto de innovación docente. Los minerales utilizados en la experiencia pertenecen a la Colección Geológica de la Universidad de León, formada por más de 2000 ejemplares. La experiencia fue evaluada por dos vías: a) comparación de los resultados académicos de los alumnos en esta práctica con resultados equivalentes de cursos académicos anteriores y, b) realización de una encuesta de satisfacción. La evaluación de la experiencia, aunque muy satisfactoria, no es concluyente, dado el reducido número de alumnos participantes. Por ello, esta experiencia se prolongará en el tiempo y se ampliará a otras asignaturas de los Grados de Ingeniería Minera y de la Energía. ostrar diversos conceptos de integración y adaptación fisiológica

Impact of Design Parameters on the Ratio of Compressive to Split Tensile Strength of Self-Compacting Concrete with Recycled Aggregate

Most concrete studies are concentrated on mechanical properties especially strength properties either directly or indirectly (fresh and durability properties). Hence, the ratio of split tensile strength to compressive strength plays a vital role in defining the concrete properties. In this review, the impact of design parameters on the strength ratio of various grades of Self-Compacting Concrete (SCC) with recycled aggregate is assessed. The design parameters considered for the study are Water to Cement (W/C) ratio, Water to Binder (W/B) ratio, Total Aggregates to Cement (TA/C) ratio, Fine Aggregate to Coarse Aggregate (FA/CA) ratio, Water to Solid (W/S) ratio in percentage, superplasticizer (SP) content (kg/cu.m), replacement percentage of recycled coarse aggregates (RCA), replacement percentage of recycled fine aggregates (RFA), fresh density and loading area of the specimen. It is observed that the strength ratio of SCC with recycled aggregates is affected by design parameters

Adaptation of a Standard Method for Water Absorption Testing of Stone Materials: The Case of a Hydrophilic Protective Coating

The historical stone heritage that we inherit must be passed on to future generations, not only in the same conditions that we found it but, if possible, in better ones. Construction also demands better and more durable materials, often stone. The protection of these materials requires knowledge of the types of rocks and their physical properties. The characterization of these properties is often standardized to ensure the quality and reproducibility of the protocols. These must be approved by entities whose purpose is to improve the quality and competitiveness of companies and to protect the environment. Standardized water absorption tests could be envisaged to test the effectiveness of certain coatings in protecting natural stone against water penetration, but we found that some steps of these protocols neglect any surface modification of the stones, and hence may not be completely effective when a hydrophilic protective coating (i.e., graphene oxide) is present. In this work, we analyze the UNE 13755/2008 standard for water absorption and propose alternative steps to adapt the norm for use with coated stones. The properties of coated stones may invalidate the interpretation of the results if the standard protocol is applied as is, so here we pay special attention to the characteristics of the coating applied, the type of water used for the test, the materials used, and the intrinsic heterogeneity of the specimens

Satisfaction Level of Engineering Students in Face-to-Face and Online Modalities under COVID-19&mdash;Case: School of Engineering of the University of Le&oacute;n, Spain

University education in times of COVID-19 was forced to seek alternative teaching/learning methods to the traditional ones, having to abruptly migrate to the online modality, changes that have repercussions on student satisfaction. That is why this study aims to compare the level of student satisfaction in face-to-face and &ldquo;forced&rdquo; online modalities under COVID-19. A quantitative, cross-sectional methodology was applied to two groups of students: Under a face-to-face modality (n = 116) and under an online modality (n = 120), to which a questionnaire was applied under a Likert scale, with four dimensions: Course design structure, content, resources, and instructor. Non-parametric statistics, specifically the Mann&ndash;Whitney U-test, were used to compare the groups. The results showed that there are significant differences in the level of satisfaction of students in the face-to-face and online &ldquo;forced&rdquo; modalities (p = 0.01984 &lt; 0.05), and the dimensions of the level of satisfaction that presented significant differences were course design structure (p = 0.04523 &lt; 0.05) and content (p = 0.00841 &lt; 0.05). The research shows that students in the face-to-face modality express a higher level of satisfaction, which is reflected in the dimension design structure of the course, specifically in its workload indicator, as well as in the dimension content, in its indicators, overlapping with other courses and materials