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This paper is aimed at the description of an optical ray propagating through underwater turbulent environment. In the first part, the description of the properties of underwater turbulence and its impact on the optical beam is presented. In the second part of the paper, method based upon Snell’s law is presented. In the third part, an approach using Ray tracing matrices is shown. The outcome of this thesis is a procedure for calculating the propagation of the optical beam through a turbulent underwater environment.

This paper is aimed at the description of an optical ray propagating through underwater turbulent environment. In the first part, the description of the properties of underwater turbulence and its impact on the optical beam is presented. In the second part of the paper, method based upon Snell’s law is presented. In the third part, an approach using Ray tracing matrices is shown. The outcome of this thesis is a procedure for calculating the propagation of the optical beam through a turbulent underwater environment.

The research question that the paper investigates is whether the usage of state of the art algorithms for point clouds registration solves the problem of multi-scale vision-based point clouds registration in mixed aerial and underwater environments. This paper reports very preliminary results on the data we have been able to procure, in the context of a coral reef restoration project nearby Magoodhoo Island (Maldives). The results obtained by exploiting state of the art algorithms are promising, considering that those data presents hard samples, in particular for their multi-scale nature (noise in captured 3D points increases with depth). However, further investigation on larger data-sets is needed to confirm the overall applicability of the current algorithms to this problem.

Methane-rich water moves through conduits beneath the seafloor whose surfaces are formed through precipitation reactions. To understand how such submarine fluid conduit and venting systems form and grow, we develop a detailed mathematical model for this reaction-advection system and we quantify the evolution of an ensemble of similar filaments. We show that this growth can be described by a superposition of advection and dispersion. We analyze analog laboratory experiments of chemical-garden type to study the growth of a single filament undergoing a precipitation reaction with the surrounding environment. We apply these findings to geological fluid conduit and venting systems, showing that their irregular trajectories can lead to very effective spreading within the surrounding seabed, thus enhancing contact and exchanges of chemicals between the conduit and external fluids. We discuss how this methane venting leads to the formation of marine authigenic carbonate rocks, and for confirmation, we analyze two field samples from the Gulf of Cadiz for composition and mineralogy of the precipitates. We note the implications of this work for hydrate melting and methane escape from the seabed.

Glauconite and celadonite coexist at the nanometre scale in Early Jurassic submarine volcanic rocks of the Betic Cordillera (southern Spain) as a result of microbial activity. Samples from the limit between the two micas, recognizable in scanning electron microscopy, have been extracted using the focussed ion beam technique and studied by high-resolution analytical electron microscopy. Both micas are present as randomly oriented differentiated small crystals in the boundary area. They define clearly distinct compositional fields with gaps affecting to Fe, Mg and K. At the lattice scale, celadonite shows a high degree of order, with homogeneous orientation of the visible lattice parameters being a difference from glauconite, formed by packets no more than 10-layers thick. Smectite layers were also detected alongside glauconite packets, in accordance with X-ray diffractograms which indicate that glauconite is a mica-smectite interstratification being more than 90 % mica layers. The compositional gap indicates that celadonite is not the endmember of the glauconitic series and the two micas represent two different structural tendencies of mica, with glauconite having more distorted octahedral sheets, indicated by systematically higher b parameters than celadonite.

[ES] Existe multitud de casos en los que, en un medio subacuático, es imposible extraer un objeto. A raíz de ello, se buscan alternativas para su extracción que presenten dichas piezas sin alterar su condición de objeto histórico sumergido. Entre estas alternativas se encuentra la realización de dibujos y fotografías, o reproducciones tridimensionales mediante moldeo y posterior reproducción, numerización 3D y técnicas de impresión, éstas últimas destinadas a casos excepcionales. En consecuencia, es el aspecto económico el que determina que la realización de moldes flexibles y posterior positivado se considere, hoy en día, como el sistema más eficaz, a través del cual es posible obtener una reproducción fiel, a escala real, del objeto o fragmento que se desea estudiar. Esta investigación se presenta con el objetivo de aportar una visión ampliada y actualizada sobre sustancias de moldeo y procesos técnicos durante la realización de moldes sobre piezas originales en un medio subacuático. En primer lugar, se establece una reflexión sobre el desarrollo tecnológico en el medio subacuático, planteando una relación lógica entre éste y los avances en los sistemas de moldeo en áreas sumergidas. En segundo lugar, se lleva a cabo una selección y, posterior, estudio de tres sustancias de moldeo a partir de las cuales se ha determinado su idoneidad. A partir de aquí, se ha optimizado un sistema que ha motivado un prototipo destinado a la obtención de moldes flexibles en medio subacuático. Durante el estudio se han examinado diversos parámetros y propiedades de los materiales mejorando su viabilidad, todo ello a partir de ensayos de laboratorio con simulación de las condiciones propias del medio marino. Finalmente, se muestra la aplicación del sistema-prototipo en condiciones reales, en medio subacuático. Esta investigación es una fuente viable para aquellos que deseen iniciarse en la obtención de moldes en entornos sumergidos., [EN] There are many cases in which, in an underwater environment, it is impossible to extract an object. As a result, alternativesare sought for their extraction that present said pieces without altering their condition as a submerged historical object. Among these alternatives is the realization of drawings and photographs, or three-dimensional reproductions through molding and subsequent reproduction, 3D digitization and printing techniques, the latter intended for exceptional cases. Consequently, it is the economic aspect that determines that the realization of flexible molds and subsequent printing is considered, today, as the most efficient system, through which it ispossible to obtain a faithful reproduction, on a real scale, of the object or fragment you want to study.This research is presented with the aim of providing an expanded and updated view on molding substances and technical processes during the making of molds on original parts in an underwater environment. In the first place, a reflection on technological development in the underwater environment is established, proposing a logical relationship between it and the advances in molding systems in submerged areas. Secondly, a selection is carried out and, later, study of three molding substances from which their suitability has been determined.From here, a system has been optimized that has motivated a prototype destined to obtain flexible molds in an underwater environment. During the study, various parameters and properties of the materials were examined, improving their viability, all based on laboratory tests with simulation of the conditions of the marine environment. Finally, the application of the prototype system is shown in real conditions, in an underwater environment. This research is a viable source for those who wish to get started in obtaining molds in submerged environments.

[ES] Existe multitud de casos en los que, en un medio subacuático, es imposible extraer un objeto. A raíz de ello, se buscan alternativas para su extracción que presenten dichas piezas sin alterar su condición de objeto histórico sumergido. Entre estas alternativas se encuentra la realización de dibujos y fotografías, o reproducciones tridimensionales mediante moldeo y posterior reproducción, numerización 3D y técnicas de impresión, éstas últimas destinadas a casos excepcionales. En consecuencia, es el aspecto económico el que determina que la realización de moldes flexibles y posterior positivado se considere, hoy en día, como el sistema más eficaz, a través del cual es posible obtener una reproducción fiel, a escala real, del objeto o fragmento que se desea estudiar. Esta investigación se presenta con el objetivo de aportar una visión ampliada y actualizada sobre sustancias de moldeo y procesos técnicos durante la realización de moldes sobre piezas originales en un medio subacuático. En primer lugar, se establece una reflexión sobre el desarrollo tecnológico en el medio subacuático, planteando una relación lógica entre éste y los avances en los sistemas de moldeo en áreas sumergidas. En segundo lugar, se lleva a cabo una selección y, posterior, estudio de tres sustancias de moldeo a partir de las cuales se ha determinado su idoneidad. A partir de aquí, se ha optimizado un sistema que ha motivado un prototipo destinado a la obtención de moldes flexibles en medio subacuático. Durante el estudio se han examinado diversos parámetros y propiedades de los materiales mejorando su viabilidad, todo ello a partir de ensayos de laboratorio con simulación de las condiciones propias del medio marino. Finalmente, se muestra la aplicación del sistema-prototipo en condiciones reales, en medio subacuático. Esta investigación es una fuente viable para aquellos que deseen iniciarse en la obtención de moldes en entornos sumergidos., [EN] There are many cases in which, in an underwater environment, it is impossible to extract an object. As a result, alternativesare sought for their extraction that present said pieces without altering their condition as a submerged historical object. Among these alternatives is the realization of drawings and photographs, or three-dimensional reproductions through molding and subsequent reproduction, 3D digitization and printing techniques, the latter intended for exceptional cases. Consequently, it is the economic aspect that determines that the realization of flexible molds and subsequent printing is considered, today, as the most efficient system, through which it ispossible to obtain a faithful reproduction, on a real scale, of the object or fragment you want to study.This research is presented with the aim of providing an expanded and updated view on molding substances and technical processes during the making of molds on original parts in an underwater environment. In the first place, a reflection on technological development in the underwater environment is established, proposing a logical relationship between it and the advances in molding systems in submerged areas. Secondly, a selection is carried out and, later, study of three molding substances from which their suitability has been determined.From here, a system has been optimized that has motivated a prototype destined to obtain flexible molds in an underwater environment. During the study, various parameters and properties of the materials were examined, improving their viability, all based on laboratory tests with simulation of the conditions of the marine environment. Finally, the application of the prototype system is shown in real conditions, in an underwater environment. This research is a viable source for those who wish to get started in obtaining molds in submerged environments.

[ES] Existe multitud de casos en los que, en un medio subacuático, es imposible extraer un objeto. A raíz de ello, se buscan alternativas para su extracción que presenten dichas piezas sin alterar su condición de objeto histórico sumergido. Entre estas alternativas se encuentra la realización de dibujos y fotografías, o reproducciones tridimensionales mediante moldeo y posterior reproducción, numerización 3D y técnicas de impresión, éstas últimas destinadas a casos excepcionales. En consecuencia, es el aspecto económico el que determina que la realización de moldes flexibles y posterior positivado se considere, hoy en día, como el sistema más eficaz, a través del cual es posible obtener una reproducción fiel, a escala real, del objeto o fragmento que se desea estudiar. Esta investigación se presenta con el objetivo de aportar una visión ampliada y actualizada sobre sustancias de moldeo y procesos técnicos durante la realización de moldes sobre piezas originales en un medio subacuático. En primer lugar, se establece una reflexión sobre el desarrollo tecnológico en el medio subacuático, planteando una relación lógica entre éste y los avances en los sistemas de moldeo en áreas sumergidas. En segundo lugar, se lleva a cabo una selección y, posterior, estudio de tres sustancias de moldeo a partir de las cuales se ha determinado su idoneidad. A partir de aquí, se ha optimizado un sistema que ha motivado un prototipo destinado a la obtención de moldes flexibles en medio subacuático. Durante el estudio se han examinado diversos parámetros y propiedades de los materiales mejorando su viabilidad, todo ello a partir de ensayos de laboratorio con simulación de las condiciones propias del medio marino. Finalmente, se muestra la aplicación del sistema-prototipo en condiciones reales, en medio subacuático. Esta investigación es una fuente viable para aquellos que deseen iniciarse en la obtención de moldes en entornos sumergidos., [EN] There are many cases in which, in an underwater environment, it is impossible to extract an object. As a result, alternativesare sought for their extraction that present said pieces without altering their condition as a submerged historical object. Among these alternatives is the realization of drawings and photographs, or three-dimensional reproductions through molding and subsequent reproduction, 3D digitization and printing techniques, the latter intended for exceptional cases. Consequently, it is the economic aspect that determines that the realization of flexible molds and subsequent printing is considered, today, as the most efficient system, through which it ispossible to obtain a faithful reproduction, on a real scale, of the object or fragment you want to study.This research is presented with the aim of providing an expanded and updated view on molding substances and technical processes during the making of molds on original parts in an underwater environment. In the first place, a reflection on technological development in the underwater environment is established, proposing a logical relationship between it and the advances in molding systems in submerged areas. Secondly, a selection is carried out and, later, study of three molding substances from which their suitability has been determined.From here, a system has been optimized that has motivated a prototype destined to obtain flexible molds in an underwater environment. During the study, various parameters and properties of the materials were examined, improving their viability, all based on laboratory tests with simulation of the conditions of the marine environment. Finally, the application of the prototype system is shown in real conditions, in an underwater environment. This research is a viable source for those who wish to get started in obtaining molds in submerged environments.

This work focuses on the study of alteration and degradation forms affecting underwater archaeological marble fragments mainly due to biological activity. The studied artefacts were recovered from the submerged archaeological park of Baia (Naples, Italy). It includes ruins of the ancient city of Baiae, which, since the 4th century AD, started to be submerged due to the bradyseism phenomenon. Diagnostic investigations were carried on 50 marbles specimens, collected from covering slabs of different pavements, from a specific area of the site called “Villa con ingresso a protiro”. Several techniques, including stereomicroscopy, polarizing optical microscopy, scanning electron microscopy and mineralogical analysis, were used to study the superficial weathering, as well as the bioerosion phenomena due to the action of marine organisms and their interaction with the substrate in relation to textural features. Results revealed that the main degradation processes can be attributable to endolithic activity, capable of excavating cavities and tunnels causing irreversible damage to the archaeological materials. In addition, samples revealed a different degree of bioerosion related to their specific intrinsic characteristics.

Tato semestrální práce je zaměřená na popis šíření optického svazku podvodním prostředím se zaměřením na vliv turbulentního proudění na odsměrování svazku. V první části práce je poskytnut popis vlastností podvodního prostředí a jejich vliv na optický svazek. V druhé části jsou prezentovány metody použitelné pro výpočet útlumu podvodního prostředí, zaměřující se na popis turbulentního prostředí. Ve třetí části je představena softwarová implementace algoritmu popsaného ve druhé části. Výsledkem práce je postup výpočtu síření optického svazku podvodním prostředím a jeho softwarová implementace., This semestral thesis is aimed at the description of the optical ray propagation through underwater environment, focusing mainly on the optical beam’s deflection by a turbulent space. In the first part of the thesis, the description of the properties of underwater environment and their impact on the optical beam is presented. In the second part, methods usable for the calculation of attenuation of an underwater environment are presented, focusing on the turbulent environment. In the third part, the software implementation of the algorithm presented in the second part is presented. The outcome of this thesis is a procedure for calculating the propagation of the optical beam through an underwater environment and its software implementation.

Tato semestrální práce je zaměřená na popis šíření optického svazku podvodním prostředím se zaměřením na vliv turbulentního proudění na odsměrování svazku. V první části práce je poskytnut popis vlastností podvodního prostředí a jejich vliv na optický svazek. V druhé části jsou prezentovány metody použitelné pro výpočet útlumu podvodního prostředí, zaměřující se na popis turbulentního prostředí. Ve třetí části je představena softwarová implementace algoritmu popsaného ve druhé části. Výsledkem práce je postup výpočtu síření optického svazku podvodním prostředím a jeho softwarová implementace., This semestral thesis is aimed at the description of the optical ray propagation through underwater environment, focusing mainly on the optical beam’s deflection by a turbulent space. In the first part of the thesis, the description of the properties of underwater environment and their impact on the optical beam is presented. In the second part, methods usable for the calculation of attenuation of an underwater environment are presented, focusing on the turbulent environment. In the third part, the software implementation of the algorithm presented in the second part is presented. The outcome of this thesis is a procedure for calculating the propagation of the optical beam through an underwater environment and its software implementation.