A molecular-based group contribution equation of state for the description of fluid phase behaviour and thermodynamic derivative properties of mixtures (SAFT-γ Mie)

An accurate knowledge of the thermophysical properties and phase behaviour of fluid mixtures is essential for the reliable design of products and processes across a wide range of chemical engineering applications, varying from the processing of petroleum fluids to the manufacturing of pharmaceuticals. Thermodynamic tools and, in the context of this work, group contribution (GC) methods are predictive approaches that are expected to play an important role in meeting these industrial needs. The principal focus of the work presented in this thesis is the development of a novel GC method based on the statistical associating fluid theory (SAFT): the SAFT-γ Mie approach. The method is developed based on a detailed molecular model and a realistic intermolecular potential, the Mie potential with variable attractive and repulsive ranges, for the description of interactions at a molecular level. Over the past decade, an increasing research effort has been devoted to developing formalisms that couple the accuracy of the SAFT equation of state (EoS) with the predictive capabilities of group contribution approaches. In the development of such methods one aims to overcome the limitations inherent to GC approaches based on activity coefficient models, such as in the well-established universal quasi-chemical functional group activity coefficient (UNIFAC) approach. A more recent landmark has been the development of heteronuclear methods within SAFT. The SAFT-γ EoS based on the square-well (SW) potential has been shown to describe accurately the phase behaviour of a wide variety of fluids. In the work presented in this thesis, SAFT-γ SW is applied to the study of the fluid phase behaviour of aqueous solutions of hydrocarbons. These mixtures are of high industrial relevance, and the accurate representation of their highly non-ideal nature is very challenging from a theoretical perspective. The SAFT-γ method is shown to perform comparatively well in predicting the behaviour of the systems examined. Nonetheless, some challenges are identified, such as the description of thermodynamic derivative properties and the description of near-critical fluid phase behaviour, where the performance of the method is shown to be less accurate. These challenges partially arise from the simplistic intermolecular square-well potential employed within SAFT-γ SW, which allows for a rigorous theoretical development, but fails to reproduce accurately finer aspects of the thermophysical behaviour of fluids, such as second-order derivative thermodynamic properties. These challenges are tackled here with the development of the SAFT-γ Mie GC approach, based on the versatile Mie intermolecular potential and a third-order treatment of the thermodynamics of the monomer segments. The SAFT-γ Mie method is applied to the study of the properties of two chemical families, n-alkanes and 2- ketones, and it is shown that a significant improvement over existing SAFT-based group contribution approaches can be achieved in the description of the pure component phase behaviour of the compounds studied. Moreover, the application of a realistic intermolecular potential is shown to allow for an excellent description of second-order derivative thermodynamic properties, and the accurate treatment of the intersegment interactions is shown to improve the performance of the method in the description of the near-critical fluid phase behaviour. The predictive capability of the method is demonstrated in the description of mixture fluid phase behaviour and excess thermodynamic properties in a predictive manner. Given the promising performance of the SAFT-γ Mie EoS, the method is applied to the case study of the solubility of two active pharmaceutical ingredients in organic solvents. The method is shown to satisfactorily predict the solubilities of the mixtures considered, based on limited experimental data for simple systems. Given the complexity of the mixtures studied, the performance of the SAFT-γ Mie is considered very encouraging and shows that there is great potential in the application of the method to this challenging field

Towards Human Society-inspired Decentralized DNN Inference

In human societies, individuals make their own decisions and they may select if and who may influence it, by e.g., consulting with people of their acquaintance or experts of a field. At a societal level, the overall knowledge is preserved and enhanced by individual person empowerment, where complicated consensus protocols have been developed over time in the form of societal mechanisms to assess, weight, combine and isolate individual people opinions. In distributed machine learning environments however, individual AI agents are merely part of a system where decisions are made in a centralized and aggregated fashion or require a fixed network topology, a practice prone to security risks and collaboration is nearly absent. For instance, Byzantine Failures may tamper both the training and inference stage of individual AI agents, leading to significantly reduced overall system performance. Inspired by societal practices, we propose a decentralized inference strategy where each individual agent is empowered to make their own decisions, by exchanging and aggregating information with other agents in their network. To this end, a ”Quality of Inference” consensus protocol (QoI) is proposed, forming a single commonly accepted inference rule applied by every individual agent. The overall system knowledge and decisions on specific manners can thereby be stored by all individual agents in a decentralized fashion, employing e.g., blockchain technology. Our experiments in classification tasks indicate that the proposed approach forms a secure decentralized inference framework, that prevents adversaries at tampering the overall process and achieves comparable performance with centralized decision aggregation methods

Αξιολόγηση της προπόνησης στην υδατοσφαίριση: η άποψη των υδατοσφαιριστών για την αποτελεσματικότητα και την ευχαρίστηση στην προπόνηση

Σκοπός της παρούσας έρευνας είναι να εξετάσει τη σχέση μεταξύ της αντιλαμβανόμενης ικανοποίησης και αποτελεσματικότητας κατά την προπόνηση υδατοσφαίρισης. Στη μελέτη συμμετείχαν 30 άρρενες υδατοσφαιριστές υψηλού επιπέδου, ηλικίας 18-32 ετών με προπονητική εμπειρία 4-20 έτη, οι οποίοι αγωνίζονται στην Α1 κατηγορία. Οι υδατοσφαιριστές συμπλήρωσαν ερωτηματολόγιο που τους δόθηκε κατά την αγωνιστική περίοδο 2016-2017 τους μήνες Δεκέμβριο – Ιανουάριο, και συμπληρώθηκε πριν από την προπόνηση. Το ερωτηματολόγιο περιλάμβανε δώδεκα ερωτήματα και οι απαντήσεις δόθηκαν σε 5βαθμη κλίμακα (1: καθόλου, 5: πάρα πολύ). Από τα αποτελέσματα φαίνεται ότι η προπόνηση τεχνικής βρίσκεται στην πρώτη προτίμηση τόσο ως προς τη αποτελεσματικότητα όσο και ως προς την ευχαρίστηση (αποτελεσματικότητα 4,4±0,77, ευχαρίστηση 4,4±0,68). Ακολουθεί σε προτίμηση η προπόνηση που αφορά φιλικό αγώνα με άλλη ομάδα (αποτελεσματικότητα 4,3±0,65, ευχαρίστηση 4,4±0,72). Αντίθετα, η προπόνηση με αποστάσεις 400 μέτρων θεωρήθηκε αναποτελεσματική και μη ευχάριστη και τοποθετείται στην τελευταία θέση των προτιμήσεων (αποτελεσματικότητα 2,8±0,91, ευχαρίστηση 1,8±1,10). Από τη μελέτη προκύπτει ότι είναι δυνατό να επιτευχθεί ταυτόχρονα αντίληψη ικανοποίησης και αποτελεσματικότητας κατά την προπόνηση στην υδατοσφαίριση. Η μελέτη αυτή μπορεί να προσφέρει χρήσιμη και πρακτική πληροφόρηση στους προπονητές έτσι ώστε να σχεδιάσουν την κατάλληλη προπόνηση με σκοπό να διατηρείται η ικανοποίηση των υδατοσφαιριστών και παράλληλα η αποτελεσματικότητα της προπόνησης σε υψηλά επίπεδα.Ν

The Antiangiogenic Properties of Adipose-Derived Mesenchymal Stem/Stromal Cells in Corneal Neovascularization in a Rabbit Model

The purpose was to study the anti-angiogenic effect of adipose-derived mesenchymal stem/stromal cells (ADMSCs) on experimentally induced corneal injuries. Corneal neovascularization (NV) was induced by incising and subsequently suturing the corneal surface in 32 New Zealand rabbits. Following suturing, the rabbits were randomly allocated into 2 groups, and received either phosphate-buffered saline (PBS) (control) or ADMSCs, both administered via three different routes. Digital images of the cornea were obtained two weeks post-incision to measure the area of neovascularized cornea. Tumor necrosis factor (TNF) was immunohistochemically assessed in the both groups. The corneal tissue was evaluated for vascular endothelial growth factor (VEGF). The extent of corneal NV in all eyes was assessed photographically by an independent observer. Fourteen days after the incisions, the degree of corneal NV was substantially decreased in the ADMSC-treated group (1.87 ± 0.9 mm2, 1.4 % ± 0.67 % of corneal surface) compared to the control and PBS-treated group (4.66 ± 1.74 mm2, 3.51 % ± 1.31 %, p < 0.001). ADMSCs significantly decreased injury-induced corneal NV in New Zealand rabbits two weeks post-treatment. This strategy has potential for use in the control of corneal NV in vivo.Â

The Antiangiogenic Properties of Adipose-Derived Mesenchymal Stem/Stromal Cells in Corneal Neovascularization in a Rabbit Model

The purpose was to study the anti-angiogenic effect of adipose-derived mesenchymal stem/stromal cells (ADMSCs) on experimentally induced corneal injuries. Corneal neovascularization (NV) was induced by incising and subsequently suturing the corneal surface in 32 New Zealand rabbits. Following suturing, the rabbits were randomly allocated into 2 groups, and received either phosphate-buffered saline (PBS) (control) or ADMSCs, both administered via three different routes. Digital images of the cornea were obtained two weeks post-incision to measure the area of neovascularized cornea. Tumor necrosis factor (TNF) was immunohistochemically assessed in the both groups. The corneal tissue was evaluated for vascular endothelial growth factor (VEGF). The extent of corneal NV in all eyes was assessed photographically by an independent observer. Fourteen days after the incisions, the degree of corneal NV was substantially decreased in the ADMSC-treated group (1.87 ± 0.9 mm2, 1.4 % ± 0.67 % of corneal surface) compared to the control and PBS-treated group (4.66 ± 1.74 mm2, 3.51 % ± 1.31 %, p < 0.001). ADMSCs significantly decreased injury-induced corneal NV in New Zealand rabbits two weeks post-treatment. This strategy has potential for use in the control of corneal NV in vivo.

Predicting the solvation of organic compounds in aqueous environments: from alkanes and alcohols to pharmaceuticals

The development of accurate models to predict the solvation, solubility, and partitioning of nonpolar and amphiphilic compounds in aqueous environments remains an important challenge. We develop state-of-the-art group-interaction models that deliver an accurate description of the thermodynamic properties of alkanes and alcohols in aqueous solution. The group-contribution formulation of the statistical associating fluid theory based on potentials with a variable Mie form (SAFT-γ Mie) is shown to provide accurate predictions of the phase equilibria, including liquid–liquid equilibria, solubility, free energies of solvation, and other infinite-dilution properties. The transferability of the model is further exemplified with predictions of octanol–water partitioning and solubility for a range of organic and pharmaceutically relevant compounds. Our SAFT-γ Mie platform is reliable for the prediction of challenging properties such as mutual solubilities of water and organic compounds which can span over 10 orders of magnitude, while remaining generic in its applicability to a wide range of compounds and thermodynamic conditions. Our work sheds light on contradictory findings related to alkane–water solubility data and the suitability of models that do not account explicitly for polarity

Roadmap on exsolution for energy applications

Over the last decade, exsolution has emerged as a powerful new method for decorating oxide supports with uniformly dispersed nanoparticles for energy and catalytic applications. Due to their exceptional anchorage, resilience to various degradation mechanisms, as well as numerous ways in which they can be produced, transformed and applied, exsolved nanoparticles have set new standards for nanoparticles in terms of activity, durability and functionality. In conjunction with multifunctional supports such as perovskite oxides, exsolution becomes a powerful platform for the design of advanced energy materials. In the following sections, we review the current status of the exsolution approach, seeking to facilitate transfer of ideas between different fields of application. We also explore future directions of research, particularly noting the multi-scale development required to take the concept forward, from fundamentals through operando studies to pilot scale demonstrations

La perception par les enseignants Grecs de FLE des stéréotypes produits sur la Grèce et les Grecs dans les médias français pendant la période de la crise économique de 2010-12

Based on the assumption that Greek teachers’ representations of France, its language and culture are positive, this thesis investigates the effect that negative stereotypes in French press reports about Greece at the time of the Greek crisis had on these representations. To achieve this objective, we use the focus group tool. Since representations cannot exist by themselves but through the interaction between peoples, and since our research focuses on the stereotypes reproduced in the French media about Greece, a historical sketch of the way France has looked at Greece over the centuries will follow the analysis of the results obtained to put them into perspective.This perspective should bring out the place and the process of operation of the representations and stereotypes between France and Greece in the teaching of FLE in Greece, a process in which a dialogue is established through a mise en abyme between the representations of two countries that serve as models for each other at different times in their history.En partant du postulat que, chez les enseignants Grecs, les représentations de la France, sa langue et sa culture, sont positives, cette thèse s’interroge sur l’effet que des stéréotypes négatifs, émis par des reportages parus dans la presse française sur la Grèce au moment de la crise grecque ont eu sur ces représentations. Pour atteindre cet objectif, nous avons recours à l’outil du groupe de discussion. Étant donné que les représentations ne peuvent pas exister par elles-mêmes mais à travers l’interaction entre peuples, et que notre recherche porte sur les stéréotypes reproduits dans les médias français à propos de la Grèce, une esquisse historique sur le regard que la France pose sur la Grèce au fil des siècles suivra l’analyse des résultats obtenus pour les mettre en perspective. Cette mise en perspective devrait faire ressortir la place et le processus de fonctionnement des représentations et stéréotypes entre la France et la Grèce dans l’enseignement du FLE en Grèce, un processus où le dialogue s’établit par le biais d’une mise en abîme entre les représentations de deux pays qui servent de modèle l’un à l’autre à des moments différents de leur histoire