Nanostructured lime-based materials for the conservation of calcareous substrates

Nanolimes, i.e. dispersions of lime (Ca(OH)2)nanoparticles in alcohol, have been extensively investigated over the last two decades as consolidation products for calcareous substrates.  The use of nanolimes for consolidation of mural paintings arises from the lack of effective and compatible consolidants for this type of substrates; the use of nanolimes was later extended also to limestone and lime-based mortars, as an alternative for silica-precursor consolidants (e.g. tetraethoxysilan - TEOS), which had shown to have a limited effectiveness and compatibility with calcareous substrates. Nanolime dispersions are characterized by a very small size of the lime particles, which should provide a proper penetration within the porous network of most building materials. In fact, a homogeneous and in-depth penetration of the consolidant is a crucial requirement when dealing with decayed stones and plasters/renders. The effectiveness of nanolime dispersions reported in literature appears controversial. Some authors observed a proper penetration and moderate consolidating action, whereas others report poor penetration, poor consolidation action and sometimes the formation of a white haze on the treated surface.  There is no agreement concerning the factors affecting the transport and deposition of the lime nanoparticles within a porous network, and the causes of the observed drawbacks are not well understood. Therefore, the main research question is:  Is nanolime a suitable alternative to silica-precursor consolidants (e.g. TEOS) for the consolidation of calcareous substrates? More specifically, the following research questions can be formulated: How and up to which extent can the effectiveness and compatibility of nanolime be improved? How can deposition of nanolime in depth be improved and the appearance of a white haze on the surface avoided? How can nanolime properties be fine-tuned to improve the effectiveness and compatibility of the treatment? What is the effect of different application methods on the effectiveness of nanolime consolidation? This research investigates and elucidates the behaviour of nanolime products for consolidation of calcareous substrates. Based on the developed knowledge, it proposes and validates a methodology (including solvent modification and application protocol) for improving the consolidation effectiveness of nanolime dispersions, making these a suitable alternative for TEOS products. Firstly, an experimental campaign was carried out in order to understand the penetration and deposition of commercial nanolimes on coarse porous calcareous substrates (Maastricht limestone). The main cause of the poor nanolime deposition in-depth was identified in the back-transport of the nanoparticles towards the drying surface, as a consequence of the high volatility and low kinetic stability of the dispersions.The modification of the nanolime properties, through the optimization of the solvent, appears thus a feasible strategy to improve the in-depth deposition of the lime nanoparticles. New nanolimes were synthetized and dispersed in a selection of solvents conferring different stability and drying rate to the obtained nanolime dispersions. A conceptual model, correlating the properties (i.e. drying rate and kinetic stability) of nanolimes dispersed in different solvents, to the moisture transport behaviour of the substrates to be treated, was conceived. The model was experimentally validated on coarse porous (Maastricht) and fine-porous (Migné) limestones.  Experimental results confirmed the predictions of the model that nanolimes dispersed in solvent with lower volatility and stability (e.g. water or butanol) have a good in-depth deposition within coarse porous networks. On the other hand, solvents with higher volatility and guaranteeing higher kinetic stability (e.g. ethanol or isopropanol) to the relative dispersions, should be preferred for substrates with fine porous networks. Fine-tuning the properties of the nanolime dispersion (by modification of the solvent) to the moisture transport behaviour of the substrate, is shown to be a successful strategy for improving in-depth deposition of lime nanoparticles.  On the basis of the obtained results, the solvent mixture was further fine-tuned using ethanol-water mixtures. Results proved that ethanol-based nanolime, mixed with a minor amount of water (5%), can provide better nanoparticles in-depth deposition within coarse porous substrates (e.g. Maastricht limestone), when compared to dispersions in pure ethanol.The application procedure of nanolime dispersions was also studied and optimized, this step being a crucial aspect for a successful consolidation; nanolimes were applied both by capillary absorption (method commonly used for laboratory tests) or by nebulization (method widely used in situ) on a coarse porous limestone and a mortar.  The research showed that results obtained by application through capillary absorption do not always correspond to those obtained by nebulization. The effectiveness and compatibility of nanolimes with improved properties and a fine-tuned application protocol were finally verified. Fresh and weathered Maastricht limestone, as well as lime-based mortars, were treated. Results showed that nanolime dispersions can guarantee an in-depth consolidation both in laboratory mortar specimens and weathered limestone, with only a moderate alteration of the total porosity and of the moisture transport properties of the investigated substrates.  Therefore, nanolime dispersions, provided that they are properly formulated and applied, can be a suitable and compatible alternative to TEOS for the consolidation of coarse porous substrates. This dissertation contributes to define guidelines to support restorers and professionals in the choice and application of nanolime dispersions for consolidation of calcareous substrates. &nbsp

Neural network-based design of freeform off-axis three-mirror telescopes for space applications

openThis work explores the development of an innovative Neural Network-based framework to automate the design of freeform off-axis three-mirror imaging systems. These optical systems, consisting of three freeform optical components arranged in a non-collinear manner, have enormous potential in fields such as space exploration and astronomy, due to their compactness and superior imaging capabilities. Starting with a comprehensive overview of freeform optics, this thesis provides an in-depth explanation of the mathematical representations, fabrication, and metrology of freeform surfaces. The challenges of realizing complex optical systems are highlighted, emphasizing the need for efficient designs. Furthermore, we analyze the advantages of freeform off-axis three-mirror imaging systems in space exploration when compared to conventional designs, providing valuable context for the developed framework. In this thesis, we propose a methodology based on Neural Networks to generate effective starting points in the design process. The framework comprises several significant phases. To begin with, we identify the key parameters of the representative system which include the Field of View, F-number, and Entrance Pupil Diameter. Next, we establish the System Parameter Space (SPS) by taking into account the design requirements and the parameters involved in the system. Then, we create a dataset through systematic sampling within the SPS, using a system evolution approach to derive the corresponding surface parameters that can fully describe the location and shape of the surfaces. The Feed-Forward Neural Network (FFNN) is trained rigorously with the given dataset. Once it is validated and proven effective, the trained FFNN can quickly produce the corresponding surface parameters when specific system parameter combinations are provided. As a result, it serves as an optimal starting point for subsequent optimizations, significantly reducing the amount of manual effort required during the design process. This novel framework represents a step forward in the fusion of advanced machine learning techniques with optical design principles. By automating and streamlining the design process, this framework sets the stage for a new era in the creation of high-performance optical systems, paving the way for future advancements in space exploration, astronomy, and various other domains.This work explores the development of an innovative Neural Network-based framework to automate the design of freeform off-axis three-mirror imaging systems. These optical systems, consisting of three freeform optical components arranged in a non-collinear manner, have enormous potential in fields such as space exploration and astronomy, due to their compactness and superior imaging capabilities. Starting with a comprehensive overview of freeform optics, this thesis provides an in-depth explanation of the mathematical representations, fabrication, and metrology of freeform surfaces. The challenges of realizing complex optical systems are highlighted, emphasizing the need for efficient designs. Furthermore, we analyze the advantages of freeform off-axis three-mirror imaging systems in space exploration when compared to conventional designs, providing valuable context for the developed framework. In this thesis, we propose a methodology based on Neural Networks to generate effective starting points in the design process. The framework comprises several significant phases. To begin with, we identify the key parameters of the representative system which include the Field of View, F-number, and Entrance Pupil Diameter. Next, we establish the System Parameter Space (SPS) by taking into account the design requirements and the parameters involved in the system. Then, we create a dataset through systematic sampling within the SPS, using a system evolution approach to derive the corresponding surface parameters that can fully describe the location and shape of the surfaces. The Feed-Forward Neural Network (FFNN) is trained rigorously with the given dataset. Once it is validated and proven effective, the trained FFNN can quickly produce the corresponding surface parameters when specific system parameter combinations are provided. As a result, it serves as an optimal starting point for subsequent optimizations, significantly reducing the amount of manual effort required during the design process. This novel framework represents a step forward in the fusion of advanced machine learning techniques with optical design principles. By automating and streamlining the design process, this framework sets the stage for a new era in the creation of high-performance optical systems, paving the way for future advancements in space exploration, astronomy, and various other domains

Generalized linear mixing model accounting for endmember variability

Endmember variability is an important factor for accurately unveiling vital information relating the pure materials and their distribution in hyperspectral images. Recently, the extended linear mixing model (ELMM) has been proposed as a modification of the linear mixing model (LMM) to consider endmember variability effects resulting mainly from illumination changes. In this paper, we further generalize the ELMM leading to a new model (GLMM) to account for more complex spectral distortions where different wavelength intervals can be affected unevenly. We also extend the existing methodology to jointly estimate the variability and the abundances for the GLMM. Simulations with real and synthetic data show that the unmixing process can benefit from the extra flexibility introduced by the GLMM

Analytical characterization of ancient mortars from the archaeological roman site of Pisões (Beja, Portugal)

The analytical characterization of mortar samples from the roman archaeological site of Pisões, located in Southern Portugal, were carried out by means of X-ray diffractometry (XRD), thermogravimetry (TGADTA), optical and electron scanning microscopy (SEM-EDS), potentiometry and combustion analysis. The Pisões archaeological complex includes a villa rustica, characterized by well-preserved mosaics and thermal baths, as well as a mill and a mausoleum. Countryside villae epitomized the Romanization of the Iberian Peninsula for over six centuries (2nd century BCE–4th century CE). Nevertheless, most of the Roman villae identified in Portugal have not yet been systematically explored and studied. This study provides valuable data on the construction materials and techniques used in Roman times in the Iberian Peninsula. The careful selection of raw materials and the use of natural and artificial pozzolanic materials can explain the favourable state of conservation, mechanical strength and long-term durability of these mortars

Hands tracking and fuzzy speed control to improve human-robot collaboration

Mestrado de dupla diplomação com a UTFPR - Universidade Tecnológica Federal do ParanáThe demand of collaborative robots has been growing in the industry in general, and with it the need for new ways to improve and make this work environment between human and robot safer and efficient. The objective of this work is to improve and make this environment safer and efficient by controlling the robot’s speed using a fuzzy approach and by getting track of the hand of the operator. For this purpose, the UR3 robot from Universal Robots and Leap Motion was used, which is a sensor capable of detecting the hand, as well as its movements, with the data obtained it was possible to create a system that has the robot’s speed as an output through fuzzy logic, and using the distance between the hand and the gripper obtained from the Leap Motion and UR3 data respectively as input to the fuzzy logic. With this it was possible to achieve satisfactory speed control, moreover, in all the tests performed the approach proved to be able to avoid collisions, and with the testing of different defuzzification methods in the fuzzy control, it was also possible to achieve smooth speed control for some of the methods used, with this in mind the system showed promise for improving Human-Robot Collaboration.A procura de robôs colaborativos tem crescido na indústria em geral, e com ela a necessidade de novas formas de melhorar e tornar este ambiente de trabalho entre o ser humano e o robô mais seguro e eficiente. O objetivo deste trabalho é melhorar e tornar este ambiente mais seguro e eficiente, controlando a velocidade do robô através de uma abordagem fuzzy e da localização da mão do operador. Para o efeito, foi utilizado o robô UR3 dos Universal Robots e do Leap Motion, o qual é um sensor capaz de detectar a mão, bem como os seus movimentos. Com os dados obtidos foi possível criar um sistema com a lógica fuzzy, tendo como saída a velocidade do robô e a entrada a distância entre a mão e a garra, obtida pelos dados do Leap Motion e do UR3, respectivamente. Com isto foi possível obter um controlo de velocidade satisfatório, além disso, em todos os testes realizados a abordagem provou conseguir evitar colisões, e com o teste de diferentes métodos de defuzzificação no controle fuzzy, também foi possível alcançar um controle suave da velocidade para alguns dos métodos utilizados, com isto em mente o sistema mostrou-se promissor para melhorar a Colaboração Humano-Robot

Inclusão digital promovendo oportunidades de trabalho e cidadania

Trabalho apresentado no 31º SEURS - Seminário de Extensão Universitária da Região Sul, realizado em Florianópolis, SC, no período de 04 a 07 de agosto de 2013 - Universidade Federal de Santa Catarina.A necessidade de ações efetivas que promovam inclusão social é premente em diversas partes do mundo. A inclusão social é base para a existência de uma sociedade mais justa e igualitária. Aliada à inclusão social está a inclusão digital, promovida pela atual relevância e amplitude de uso das tecnologias de informação e comunicação, seja para trabalho, entretenimento, instrução, busca e troca de informação ou interação social. Como forma de prover a inclusão digital e que esta contribua para a inclusão social, as ações realizadas através de projeto - apoiado pelo edital Proext 2013 do Ministério da Educação e realizado pela UTFPR, Câmpus Pato Branco - visam utilizar a informática como meio de prover inclusão e preparar jovens para atuação no mercado de trabalho. Para a realização das atividades é utilizada a infraestrutura da UTFPR e das comunidades de Nova Aurora em Abelardo Luz, SC, e Vila Rural em Clevelândia, PR. Os executores do projeto são docentes, discentes e técnicos da UTFPR, Câmpus Pato Branco. As ações se agrupam em: inclusão digital e cidadania com cursos na área de informática, incluindo iniciação a robótica e uso de novas tecnologias, como os tablets; preparação para o mercado de trabalho com cursos de Linux e seus aplicativos e desenvolvimento de páginas web; recomposição de computadores com coleta de equipamentos, recomposição e composição de laboratórios para Instituições Educacionais e Assistenciais. A metodologia das ações instrucionais tem como base cursos práticos realizados na UTFPR e nas comunidades. Nas comunidades atendidas foram implantados laboratórios de informática com recursos do próprio Edital. Esses laboratórios, com acesso à Internet, permanecerão nas comunidades. Em termos de resultados, destaca-se o número de pessoas capacitadas, sejam os jovens para o mercado de trabalho, sejam as demais pessoas com condições de interagir com tecnologias de informação e comunicação na busca de conhecimento, informação e interação

Taiwan's New Southbound Policy in the U.S. free and open Indo-Pacific

For more about the East-West Center, see http://www.eastwestcenter.org/Russell Hsiao and Marzia Borsoi-Kelly, Executive Director and Program Manager at Global Taiwan Institute, respectively, explain that "While other presidents before Tsai had their own versions of a southbound policy, the NSP is more strategic.

Landing Throttleable Hybrid Rockets with Hierarchical Reinforcement Learning in a Simulated Environment

In this paper, I develop a hierarchical Markov Decision Process (MDP) structure for completing the task of vertical rocket landing. I start by covering the background of this problem, and formally defining its constraints. In order to reduce mistakes while formulating different MDPs, I define and develop the criteria for a standardized MDP definition format. I then decompose the problem into several sub-problems of vertical landing, namely velocity control and vertical stability control. By exploiting MDP coupling and symmetrical properties, I am able to significantly reduce the size of the state space compared to a unified MDP formulation. This paper contains two major contributions: 1) the development of a standardized MDP definition framework and 2) a hierarchical MDP structure that is able to successfully land the rocket within the goal bounds more than 95% of the time. I validate this approach by comparing its performance to a baseline RRT search, underlining the advantages of rapid-decision making compared to online planning in the field of Artificial Intelligence (AI)