Quantum Non-Markovianity: Characterization, Quantification and Detection

We present a comprehensive and up to date review on the concept of quantum non-Markovianity, a central theme in the theory of open quantum systems. We introduce the concept of quantum Markovian process as a generalization of the classical definition of Markovianity via the so-called divisibility property and relate this notion to the intuitive idea that links non-Markovianity with the persistence of memory effects. A detailed comparison with other definitions presented in the literature is provided. We then discuss several existing proposals to quantify the degree of non-Markovianity of quantum dynamics and to witness non-Markovian behavior, the latter providing sufficient conditions to detect deviations from strict Markovianity. Finally, we conclude by enumerating some timely open problems in the field and provide an outlook on possible research directions.Comment: Review article. Close to published versio

Medida de la durabilidad de dos tratamientos de hidrofugación aplicados a rocas graníticas

The durability of two water-repellents for granitic stonework was determined. Weathered and sound samples of granites widely used in building construction and restoration in Galicia (NW Spain) were treated with water repellents of known efficacy, and then subjected to two artificial weathering tests: prolonged exposure to UV light, and sodium sulphate crystallization cycles. In both tests, but especially in the salt crystallization cycles, both treatments rapidly lost their water-repellency. Furthermore, the hydrophobic layer of water repellent impeded salt mobility, favouring fissuration parallel to the treated surface, which was eventually shed in the form of a plaque.Se presentan los resultados de la durabilidad de dos tratamientos de hidrofugación aplicados a rocas graníticas ampliamente utilizados en la construcción de edificios en Galicia (Noroeste de España). Tras la evaluación de la eficacia de dichos tratamientos, cuyos resultados se presentaron en un trabajo anterior, se someten las muestras tratadas a dos ensayos diferentes de envejecimiento acelerado: ciclos de exposición a la luz ultravioleta y ciclos de cristalización de sulfato de sodio. Los productos hidrofugantes muestran una escasa resistencia a ambos ensayos, sobre todo a los ciclos de cristalización de sulfato de sodio; esta débil durabilidad se manifiesta en una rápida pérdida de sus propiedades hidrofugantes. Así mismo, se observa que la presencia de la capa hidrófoba en la piedra funciona como una barrera frente a la movilidad de sales, lo que ocasiona el total desprendimiento de aquella y un fuerte deterioro del material rocoso

Medida de la eficacia de dos hidrofugantes aplicados a rocas graníticas

We evaluated the efficacy of two water-repellents applied to three types of granitic rock widely used in building construction and restoration in Galicia (NW Spain). The depth of penetration of the water-repellents was determined by measuring capillary absorption by the treated rock. The efficacies of the water-repellent were evaluated in terms of two parameters characteristic of surface wet: water-rock contact angle and the time taken for absorption of microgroplets. The effects of the treatments on the rocks' surface color and permeability to water vapor were also determined. The results indicate that neither water-repellent effectively penetrates the rock surface, and both induce undesirably high reductions in vapor permeability. Notwithstanding, both agents effectively improved the rocks' resistance to surface wetting, without altering its surface color. Overall, determination of water-rock contact angle and the time taken for absorption of microdroplets, together with colorimetric characterization of the treated rock, constitutes an useful approach to evaluation of the effects of water-repellents on granitic rocks. Nonetheless, it should be borne in mind that the marked heterogeneity of this type of rock, and the associated mineralogy and dominant type of fissuration are sources of considerable variation in the measurement parameters.Se presentan los resultados de la aplicación de dos tratamientos hidrofugantes a tres rocas graníticas ampliamente utilizadas en la construcción y restauración en Galicia. Se ha determinado la profundidad de penetración de los hidrofugantes a través de la absorción capilar, la eficacia de los tratamientos comparando dos parámetros relacionados con el mojado superficial (ángulo de contacto roca-agua y tiempo de absorción de microgotas), y las variaciones en el color y en la permeabilidad al vapor. Se comprueba que si bien ambos tratamientos penetran deforma muy escasa en las rocas graníticas y reducen significativamente la permeabilidad al vapor, mejoran sensiblemente su comportamiento frente al mojado superficial sin modificar el color original. El ángulo de contacto, el tiempo de absorción de microgotas y la determinación colorimétrica utilizada, constituyen una buena metodología en la evaluación de los efectos de tratamientos hidrofugantes en rocas graníticas; sin embargo, el fuerte carácter heterogéneo este tipo de rocas, la mineralogía y el tipo de fisuración predominante, suponen un factor de variación significativo en la determinación de estos parámetros

Tratamientos de consolidación e hidrofugación aplicados a sustratos graníticos húmedos y contaminados por sales solubles

A comparison was made of the efficacy of two consolidants and two water repellents applied to samples of granite under optimum conditions, with the efficacy of the same products applied to the granite in the presence of soluble salts or water. The amount of product absorbed and the amount of dry polymer remaining after treatment were compared. The results show that the presence of water and soluble salts in the stone significantly modifies the consumption of the products (in particular the water repellents) and also the level of dry polymer retained. The water repellents were found to be much less effective when the substrate contained salts, whereas the presence of water did not appear to influence their efficacy. The lack of correlation between uptake, active dry polymer, and efficacy led to the conclusion that the presence of salts or water markedly changes the kinetics of the polymerization of the products.Se analiza la eficacia de dos consolidantes y dos hidrofugantes aplicados a rocas graníticas en condiciones óptimas comparativamente a la eficacia de los mismos productos aplicados sobre los mismos sustratos conteniendo cierta cantidad de sales solubles o de agua. Se compara la cantidad de producto absorbido y la cantidad de materia seca presente tras el curado. Los resultados indican que la presencia de agua y de sales solubles en la piedra modifica significativamente el consumo de los productos, sobre todo el de los hidrofugantes, así como la cantidad de materia seca. Se observa, asimismo, un fuerte detrimento en la eficacia de los hidrofugantes cuando el sustrato contiene sales mientras que, al contrario, la presencia de agua no parece infiuir en dicha eficacia. La falta de correlación entre el consumo, materia seca activa y eficacia lleva a concluir que la presencia de sales o agua modifica sensiblemente la cinética de la polimeración de los productos

Mechanical and hygrothermal properties of hemp-silica bio-composites

This research investigated the development of a fast-drying silica-based binder for hemp concrete products with enhanced mechanical and thermal properties. Hemp-silica bio-composites were prepared by mixing hemp shivs with a two-component binder system composed of liquid sodium silicate and tributyl citrate (TBC). Compressive strength, thermal conductivity, moisture buffering value, cyclic moisture resistance and microstructure of hemp-silica composites were analysed, and the results were compared with those of hemp-lime concrete. Hemp-silica blocks with shiv-liquid sodium silicate mass ratio of 1:3.75 and TBC content of 37.5 wt% of sodium silicate dry matter produced a compressive strength of 0.56 MPa only after 3 days of drying and 1.92 MPa after 28 days. These were higher than hemp-lime blocks at the same density range. Hemp-silica panels showed a thermal conductivity of 0.101 W/mK and an excellent moisture buffering value of 3.49. Hemp silica formed an open porosity with large air gaps between the particles and a water-resistance silica-based layer on the shiv surface producing a higher moisture resistance compared to hemp-lime systems. This paper focuses on the development of a novel fast-drying binder system with a potential for use in conjunction with other lingnocellular plant aggregates to form low-carbon and efficient multifunctional building materials

Methodology for the study of weathering of granitic building stone

[Resumen] En este trabajo se presentan los resultados de los análisis realizados sobre un sillar granítico extraído del Claustro de San Martín Pinario (Santiago de Compostela). La oportunidad de disponer de esta muestra nos ha permitido realizar una serie de determinaciones que no siempre es posible llevar a cabo en los monumentos. Además del análisis desde el punto de vista petrográfico-mineralógico y geoquímico, se han determinado varias propiedades físicas. Por una parte, aquellas que condicionan el movimiento del agua a través de la roca, como la porosidad accesible al agua, grados de absorción y saturación y coeficiente de capilaridad, y por otra, aquellas que definen la resistencia mecánica del material a la compresión y flexotracción. También se han determinado los coeficientes de dilatación térmica y por hinchamiento. Estas propiedades son fundamentalmente para caracterizar una roca como material de construcción y pueden dar la clave de su comportamiento frente a diversos mecanismos de alteración.[Abstract] We report the results of analyses of a granite ashlar extracted during a restoration work from the cloister of the Monatery of San Martín Pinario (Santiago de Compostela, Spain). Petrographic, mineralogical and geochemical analyses were supplemented by determination of physical properties governing water transport in the stone (open porosity, degree of absortion and saturation, and capillary coefficient), compressive and bending strength and termal dilation coefficient and swelling coefficient. These fundamental characteristics of building stone may throw light on its response to diverse weathering mecanism