Performance of graphene oxide as a water-repellent coating nanomaterial to extend the service life of concrete structures.

Surface treatments help to protect the built heritage against damage (environmental, accidental, etc.), reducing repair and restitution costs and increasing the useful life of building materials. The use of nanomaterials is currently the most important field of research in surface treatment technology for the preservation of building materials and, more specifically, to improve their durability and prevent their deterioration, extending their useful life. This paper studies the influence of a graphene oxide (GO) suspension as a surface treatment on the properties of concrete. The results indicate that, at best, surface treatment with GO can decrease both the water absorption and capillary absorption of concrete by about 15 %. The increase in the amount of GO deposited as a surface treatment leads to a further reduction in concrete water absorption. It is shown that, at best, GO coating also reduces water penetration at low and high pressures by approximately 20 % and 60 %, respectively. In addition, scanning electron microscopy analysis shows that GO surface treatment facilitates the hydration process and densifies the concrete microstructure. A simple aqueous suspension of GO is revealed as a tool with a high potential to protect concrete surfaces in a fast and cost-effective way, thanks to the easy application by spraying and the small amount of material needed to obtain great results.

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.

Soft Skills and STEM Education: Vision of the European University EURECA-PRO.

Science, Technology, Engineering, and Mathematics (STEM) disciplines play an increasingly important role in the current socio-economic context. Higher education systems are working to equip students with the appropriate skills and competencies to cope with current demands and, in particular, to join a labour market strongly informed by STEM disciplines. Many such skills are non-disciplinary and are known as transversal or soft skills. Soft skills, including interpersonal and socio-emotional skills, are highly sought after in the labour market. These skills not only reflect personal abilities but also draw on concepts, such as social responsibility, creativity, ethics, and emotional intelligence. The European University on Responsible Consumption and Production (EURECA-PRO) seeks to foster soft skills development in our activities and curricula.

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.

SARS-CoV-2 viability under different meteorological conditions, surfaces, fluids and transmission between animals.

Since the COVID-19 outbreak, researchers have tried to characterise the novel coronavirus SARS-CoV-2 to better understand the pathogenic mechanisms of the virus and prevent further dissemination. As a consequence, there has been a bloom in scientific research papers focused on the behaviour of the virus in different environmental contexts. Nevertheless, despite these efforts and due to its novelty, available information about this coronavirus is limited, as several research studies are still ongoing. This review aims to shed light on this issue. To that end, we have examined the scientific literature to date regarding the viability of SARS-CoV-2 on surfaces and fluids or under different environmental conditions (temperature, precipitation and UV radiation). We have also addressed the role of animals in the transmission of this coronavirus.

Human mortality seasonality in Castile-León, Spain, between 1980 and 1998: the influence of temperature, pressure and humidity.

This study was carried out in the region of Castile and Leon, Spain, from 1980 to 1998 and analyzes the relationship between the number of monthly deaths caused by cardiovascular, respiratory and digestive diseases and three meteorological variables: temperature, pressure and humidity. One of the innovations in this study is the application of principal component analysis in a way that differs from its usual application: one single series representing the whole region was constructed for each meteorological variable from the series of eight weather stations. Annual and seasonal mortality trends were also studied. Cardiovascular diseases are the leading cause of death in Castile and Leon. The mortality related to cardiovascular, respiratory and digestive systems shows a statistically significant rising trend across the study period (an annual increase of 6, 16 and 4 per thousand, respectively). The pressure at which mortality is lowest is approximately the same for all causes of death (about 915 hPa), but temperature values vary greatly (16.8-19.7 degrees C for the mean, 10.9-18.1 degrees C for the minimum, and 24.1-27.2 degrees C for the maximum temperature). The most comfortable temperatures for patients with cardiovascular diseases (16.8 degrees C) are apparently lower than those for patients with respiratory diseases (18.1 degrees C), which are, in turn, lower than in the case of diseases of the digestive system (19.7 degrees C). Finally, the optimal humidity for patients with respiratory diseases is the lowest (24%) among the diseases, and the highest (51%) corresponds to diseases of the digestive system, while the optimal relative humidity for the cardiovascular system is 45%.