The importance of understanding the effects of rainfall on different materials over time makes it essential to carry out controlled tests to reduce analysis time. Rainfall simulators have been in use for decades and have been implemented as technology and knowledge of the physical behavior of water advanced. There are two main types of rainfall simulators: gravity simulators and pressure simulators. In the former, the drop velocity is normally smaller than the terminal velocity reached by natural droplets; in the latter, the drop size is too small to be representative and has far more speed than the natural speed for those sizes. To solve this problem, a simulator has been developed where the terminal velocity of the raindrops is reached and the drop size can be varied by different nozzles of variable sizes, adapting it to the conditions of a given region. In this study, conditions similar to the rainfall conditions of the city of León have been achieved. This paper presents the design of a rainfall simulator that recreates different rainfall conditions and rainwater composition and its calibration process.

Acid rain is a problem that despite efforts to reduce atmospheric pollution, continues to impact not only countries where there is a high production of pollutants, but also transboundary areas to which the pollutants are transported. In addition to its effects on human health, there are also the effects on infrastructure and the consequences that this entails. This study on the effect of rain and acid rain on calcareous materials highlights the need for protection of buildings constructed from these materials, many of which are part of the cultural heritage. The effects caused by rain and acid rain were studied using a rain simulator whose features allow the simulation of natural conditions as realistically as possible. In the same way, the effect of a coating synthesized from nanomaterials, which has been shown to serve as protection against the degradation caused by rain, was analyzed. In addition to a long-lasting protection of the stone material, this type of coating avoids the need for the replacement of elements and the recurrent cleaning of degraded parts. It also avoids the accumulation of parts on the ground, the transport of personnel, work materials and raw materials, thereby contributing to the reduction of the carbon footprint and water savings, which in turn reduces the production of pollutants that cause acid rain.

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.

La Piedra natural presenta una variabilidad composicional que a menudo pasa desapercibida mediante las inspecciones visuales convencionales en cantera. En este trabajo se caracteriza la roca carbonatada ornamental "Emperador Castril" dicha heterogeneidad química y mineralógica mediante la integración de técnicas espectroscópicas (espectroscopia de reflectancia difusa de laboratorio e imágenes hiperespectrales). La validación se realiza con técnicas analíticas (difracción y fluorescencia de rayos X) sobre muestras comerciales y de descarte. La espectroscopia de reflectancia VNIR-SWIR puntual permitió identificar bandas diagnósticas de la dolomita (~2325 nm), presencia de arcillas y contenido de hierro. Posteriormente, las imágenes hiperespectrales permitieron conocer la distribución irregular de las distintas fases minerales aplicando el algoritmo de clasificación Spectral Angle Mapper (SAM). Todas las técnicas mostraron coherencia en revelar una composición predominantemente dolomítica, con presencia minoritaria de calcita y, en casos específicos, cuarzo y fases arcillosas, además de confirmar una variabilidad composicional ligada al mayor aporte detrítico. Se concluye que el uso de tecnologías espectroscópicas in situ puede optimizar la clasificación del material y la eficiencia de la explotación, reduciendo los residuos mineros conforme a la normativa europea.

: Los datos de alta resolución espectral y espacial registrados por el espectrómetro de imágenes AHS (Airborne Hyperspectral Scanner) proporcionan una información muy útil para la exploración de recursos minerales y rocas industriales mediante la cartografía de la composición mineral de formas del relieve. El área de estudio se localiza en la cuenca sedimentaria del Tajo en unidades formadas por rocas arcillosas, evaporíticas, carbonatadas terciarias y sedimentos detríticos asociados a las unidades morfosedimentarias cuaternarias principalmente de origen fluvial. El estudio se basa en la respuesta espectral de minerales clave como carbonatos, sulfatos y arcillas, con el fin de cartografiar su presencia en las superficies planas y alomadas en la zona situada entre los ríos Tajo, Tajuña y Jarama. Simultáneamente a la campaña de vuelo, se llevó a cabo un estudio de espectrorradiometría de campo para caracterizar la variabilidad mineral de las distintas formas del relieve en el intervalo de longitud de onda visible-infrarrojo cercano e infrarrojo de onda corta (VNIR-SWIR, 350-2500 nm) utilizando un espectrorradiómetro ASD FieldSpec-4. Se utilizaron muestras de campo para espectroscopía de reflectancia de laboratorio y difracción de rayos X con el fin de vincular la respuesta espectral con la caracterización mineralógica de las muestras y validar el resultado de la cartografía obtenida. También se emplearon varias técnicas cartográficas: cocientes de bandas para realzar los rasgos de absorción diagnósticos de los minerales de interés y el algoritmo SAM (Spectral Angle Mapper). Los resultados muestran un patrón de mezcla complicado entre minerales de arcilla, carbonatos y sulfatos debido al solapamiento de algunos rasgos de absorción en determinadas longitudes de onda, pero bien determinado espacialmente, siendo las zonas con presencia de yeso las mejor diferenciadas, proporcionando una localización detallada de las abundancias minerales de la superficie.